# Class D Amplifier For SQ



## aranthop (Dec 30, 2007)

Any of you using class d amps on all speakers? Pros? Cons?


----------



## unpredictableacts (Aug 16, 2006)

isnt that PDX alpines class d.....sound fine to me.


----------



## cheesehead (Mar 20, 2007)

I'm using a avionix class d on my midbass. It's working/sounding decent to me. But I haven't tried anything else yet to compare it to.


----------



## aranthop (Dec 30, 2007)

how about for midrange and tweets? The class d amplifiers are very much capable handling subs though.


----------



## cheesehead (Mar 20, 2007)

aranthop said:


> how about for midrange and tweets? The class d amplifiers are very much capable handling subs though.


 Sorry I can't help you there. Maybe someone else will chime in.


----------



## BTA (Nov 5, 2005)

Search for Alpine PDX or Kenwood x4r


----------



## agentk98 (Oct 31, 2006)

PDX amps get pretty decent reviews. Check out the PDX 4.150. Last i checked, they were still ideal for a 4 way full-active setup


----------



## MadMaxSE-L (Oct 19, 2006)

I am running the Eclipse XA4000 amps on my subs and on my tweeters/mids at the moment - sounds fantastic (limited by tuning currently...). They are considered "full range" class D amps.

PROS:
- lower power consumption
- smaller power wire
- less heat porduction
- often smaller footprint (updated from babds post below) 

CONS
- none that I can think of


----------



## Babs (Jul 6, 2007)

Major pro... "Some" class-D's are much smaller... easier choosing install locations.


----------



## typericey (May 13, 2006)

Alto Mobile makes very compact full range car audio amps. never auditioned them, but online reviews say that the high frequencies are rolled off. Could be a characteristic of full range class d amps but i hesitate to generalize. just something to watch out for and consider. but then again, rolled off highs is not always a bad thing.


----------



## 89grand (Nov 23, 2006)

I don't think they'd sell full range class D amps if you could tell the difference in sound quality. 

Some people claim class A/B is better for full range and subs, but I seriously doubt those people could tell the difference in a blind test.


----------



## OgreDave (Jul 13, 2005)

I had PDX on midrange/sub, they sounded fine .. I'm all A/B now, though.


----------



## AAAAAAA (Oct 5, 2007)

I am running sony full range class D's, I love them, nothing seems out of the ordinary to my ears, but are they ever small! Power to size is exellent.

I did play a 20khz test tone that I could barely hear, but that's probably my ear's limitations hehe, I should check that out and compare, I have AB amps for testing at my disposal.

Can anyone else hear 20khz well at all? hehehe


----------



## MadMaxSE-L (Oct 19, 2006)

AAAAAAA said:


> Can anyone else hear 20khz well at all? hehehe


I used to be able to hear it in when I was 16 and had my Bronco. I had 4 12's and 2000w of A/B power on tap and my truck almost rattled apart


----------



## FoxPro5 (Feb 14, 2006)

"Is amplifier topology an important aspect in SQ?"

Religion says "yes"; science says "no."

At the end of the day, it depends which God you believe in the most, I guess.

If Genesis came out with an awesome new amp and told everyone that it's the benchmark for Class A/B sound and performance....but then one year later said, "just kidding, it's a Class D haha" do you actually think someone...in all that time...would even say "I don't know this kinda sound's like a Class D amp to me!?!?!?!?


----------



## aranthop (Dec 30, 2007)

FoxPro5 said:


> "Is amplifier topology an important aspect in SQ?"
> 
> Religion says "yes"; science says "no."
> 
> ...


Very well said foxpro5, i won't argue with that. My main concern really is if doing the right thing in running 4-way full-active (lotus reference tw/mb, lotus rm110 mr, and 1 pc. lotus 300w s) using alto mobile (4x75, 2x150, 1x250) which, footprint wise, is very ideal to me. Another thing, I have read on another thread that it's a no-no to use class D amps for tweets and mids. How are these true?


----------



## FoxPro5 (Feb 14, 2006)

aranthop said:


> Very well said foxpro5, i won't argue with that. My main concern really is if doing the right thing in running 4-way full-active (lotus reference tw/mb, lotus rm110 mr, and 1 pc. lotus 300w s) using alto mobile (4x75, 2x150, 1x250) which, footprint wise, is very ideal to me. Another thing, I have read on another thread that *it's a no-no to use class D amps for tweets and mids*. How are these true?


It's quite alright, your speakers don't care. 

Well I've run that exact full Lotus set up on several different amps, Class D being one of them, and the SQ of the system had FAR LESS to do with the amplifier design/topology and MUCH MORE to do with the big piece of the pie: install and tuning. A speaker has, according to some, 100x more distortion than any amp. Plus the car environment itself will shape the sound much more the what's used to amplify it. 

Those Alto Mobile amps look great, buy them!


----------



## aranthop (Dec 30, 2007)

hi foxpro,

can you explain this further:
_
"the SQ of the system had FAR LESS to do with the amplifier design/topology and MUCH MORE to do with the big piece of the pie: install and tuning."_


----------



## t3sn4f2 (Jan 3, 2007)

aranthop said:


> hi foxpro,
> 
> can you explain this further:
> _
> "the SQ of the system had FAR LESS to do with the amplifier design/topology and MUCH MORE to do with the big piece of the pie: install and tuning."_


Think about it like this, you need a good TV to see the difference between a cheap DVD player and a good one. If your speaker setup and install is not up to the task it would be like comparing those DVD players on an 80's projection TV. Where that TVs inherent short comings will far outweigh and _drown out_ the shortcomings of the DVD players being compared.


----------



## MuTT (Apr 4, 2007)

In other words if your speakers (because of distortion and the car environment) can only get to say "80% SQ", and your class A/B amp can play to "95% SQ", but the D class can only get play to "90 SQ", you're still only getting "80% SQ"
...weakest link syndrome.


note: yes, I'm aware that there is no such scores, just using fictitious numbers and ratings as a way to help explain.


----------



## FoxPro5 (Feb 14, 2006)

aranthop said:


> hi foxpro,
> 
> can you explain this further:
> _
> "the SQ of the system had FAR LESS to do with the amplifier design/topology and MUCH MORE to do with the big piece of the pie: install and tuning."_


Rough guidelines when planning a system:
30% equipment (Dual amps or Audison Thesis??)
30% install (where to put the speakers and why)
40% tuning (TRYING to achieve stereo in your car)

The majority (70%) of the sound quality of the system depends on install and tuning, not on equipment. Just my take, that's all.


----------



## michaelsil1 (May 24, 2007)

There are too many variables involved in achieving SQ in a car.

If everything has been addressed (to the best of your ability) then you will definitely notice a difference between Class D Amplification and Class A/B.

The best cars I've heard were not using Class D.


----------



## t3sn4f2 (Jan 3, 2007)

michaelsil1 said:


> There are too many variables involved in achieving SQ in a car.
> 
> If everything has been addressed (to the best of your ability) then you will *definitely* notice a difference between Class D Amplification and Class A/B.
> 
> The best cars I've heard were not using Class D.


::cough cough::


----------



## AAAAAAA (Oct 5, 2007)

^Obviously since full range class D hasn't been around more then a couple of years. Only now are their multiple offerings.

Before it was only eclipse, pioneer and then Alpine.
The first 2 didn't get much notice since they were still big.


----------



## FoxPro5 (Feb 14, 2006)

michaelsil1 said:


> If everything has been addressed (to the best of your ability) then you will *definitely notice *a difference between Class D Amplification and Class A/B.
> 
> The best cars I've heard were not using Class D.


Dogmatic ********, plain and simple. 

Buying an amp for it's "SQ" is like buying Mountain Dew for it's nutritional value.


----------



## FoxPro5 (Feb 14, 2006)

AAAAAAA said:


> ^Obviously since full range class D hasn't been around more then a couple of years. Only now are their multiple offerings.
> 
> Before it was only eclipse, pioneer and then Alpine.
> The first 2 didn't get much notice since they were still big.


Eclipse has been using B&O technology since at least 2002 or so.


----------



## bassfromspace (Jun 28, 2016)

michaelsil1 said:


> There are too many variables involved in achieving SQ in a car.
> 
> If everything has been addressed (to the best of your ability) then you will definitely notice a difference between Class D Amplification and Class A/B.
> 
> The best cars I've heard were not using Class D.


I'd disagree with you on this account.


----------



## MadMaxSE-L (Oct 19, 2006)

michaelsil1 said:


> There are too many variables involved in achieving SQ in a car.
> 
> If everything has been addressed (to the best of your ability) then you will definitely notice a difference between Class D Amplification and Class A/B.
> 
> The best cars I've heard were not using Class D.


Where's the LOL/ROFL smiley face?


----------



## michaelsil1 (May 24, 2007)

bassfromspace said:


> I'd disagree with you on this account.


I know I know I set myself up for ridicule. :blush: 

I was running Class D now I'm running Class A/B front stage; there's a night and day difference for the better.


----------



## FoxPro5 (Feb 14, 2006)

michaelsil1 said:


> I know I know I set myself up for ridicule. :blush:
> 
> I was running Class D now I'm running Class A/B front stage; there's a night and day difference for the better.


So you're talking about "taste" in amps, then? How can you attribute what you heard to design?

I was smoking Marlboro and then switched to Camels....for my lungs; there's a night and day difference for the better.


----------



## michaelsil1 (May 24, 2007)

FoxPro5 said:


> So you're talking about "taste" in amps, then? How can you attribute what you heard to design?
> 
> I was smoking Marlboro and then switched to Camels....for my lungs; there's a night and day difference for the better.


Yes I'm talking about taste! 


I don't like the taste of distortion!


----------



## 89grand (Nov 23, 2006)

Hmmmm...so class D amps have a lot of distortion?

I never knew that.


----------



## MadMaxSE-L (Oct 19, 2006)

89grand said:


> Hmmmm...so class D amps have a lot of distortion?
> 
> I never knew that.


Man, I wish someone had told me that; I'd never have put class D's on my mids & tweets

I just don't see how a class d amp with the SAME distortion specs as class a/b amp can have more distortion...


----------



## michaelsil1 (May 24, 2007)

MadMaxSE-L said:


> Man, I wish someone had told me that; I'd never have put class D's on my mids & tweets
> 
> I just don't see how a class d amp with the SAME distortion specs as class a/b amp can have more distortion...


I'm sure there are some lousy Class A/B Amps.  

I have better distortion specs now than I did with my Alpine PDX 4.150.


----------



## bassfromspace (Jun 28, 2016)

michaelsil1 said:


> I'm sure there are some lousy Class A/B Amps.
> 
> I have better distortion specs now than I did with my Alpine PDX 4.150.


If your ear can discern the difference in distortion equal to the difference in those two specs, there's a TON of money out there waiting for you.


----------



## MadMaxSE-L (Oct 19, 2006)

michaelsil1 said:


> I'm sure there are some lousy Class A/B Amps.


No doubt; but that's not what we are talking about. 

What you are trying to argue is that there is less distortion in a class a/b amp than there is in a full range class d amp - both with a similar harmonic distortion spec - simply because of the topology. I'm just wondering how there can be; it just doesn't make sense...



michaelsil1 said:


> I have better distortion specs now than I did with my Alpine PDX 4.150.


And what exactly is there to say that that has anything at all to do with amplifier topology?


----------



## 89grand (Nov 23, 2006)

Besides that, what are the differences between the two amps distortion specs, like .01% vs .08%?

If you can hear that difference, it must be torture just listening to music.


----------



## MadMaxSE-L (Oct 19, 2006)

89grand said:


> Besides that, what are the differences between the two amps distortion specs, like .01% vs .08%?
> 
> If you can hear that difference, it must be torture just listening to music.


It sure must be; especially since the speakers have many times that amount of distortion.


----------



## bassfromspace (Jun 28, 2016)

We still love you Michael.


----------



## michaelsil1 (May 24, 2007)

I thought the topic was SQ with a Class D Amplifier; if you have achieved that and satisfied your requirements great.

I personally wasn't happy with Class D Amplification!


----------



## michaelsil1 (May 24, 2007)

bassfromspace said:


> We still love you Michael.


Thank you!!


----------



## t3sn4f2 (Jan 3, 2007)

michaelsil1 said:


> I thought the topic was SQ with a Class D Amplifier; if you have achieved that and satisfied your requirements great.
> 
> *I personally wasn't happy with Class D Amplification!*


Now this, no one can argue. Well said


----------



## FoxPro5 (Feb 14, 2006)

cajunner said:


> general consensus is that a/b with high idle is best for soundq, which is why the class A stuff has a nice following, *it isn't all marketing*.


You're right, it's also the delusion of those that buy into it. 

Be sure to read the listener comments section at the end: http://bruce.coppola.name/audio/Amp_Sound.pdf

What you hear vs what you think you hear:
http://www.hometheaterhifi.com/volume_5_3/essaywhatwehearseptember98.html


----------



## FoxPro5 (Feb 14, 2006)

cajunner said:


> I will not read that!
> 
> It doesn't fit my previously ordered set of parallels, conventional thinking biases and need to fit in the group....


Which is all the more reason to.  Of course it won't fit, there's no room in your mind for anything else as you've already closed the door and made up your mind. Come to the dark side where all amps that test the same sound the same. We have all sorts of wattifiers waiting to trick you.


----------



## vecc205 (Nov 18, 2007)

A class D full range amp will sound very similar to a class A/B in a car IMO. Speaker placement and tuning will be more important to the sound of the overall system though. If I had the choice I would choose to run an A/B on my components because I can get 100-200 watts in a decent size amp for me anyway and get usually better specs all around without having to pay a big price difference from an A/B to a D. Now if I wanted a small footprint with more output than I would use a D. To me the only advantage of the class D is the efficiency versus the A/B and thats it. So I wouldn't worry about the sq of a A/B vs D if you can fit it use an A/B if you can't go with the D.


----------



## MadMaxSE-L (Oct 19, 2006)

vecc205 said:


> A class D full range amp will sound very similar to a class A/B in a car IMO. Speaker placement and tuning will be more important to the sound of the overall system though. If I had the choice I would choose to run an A/B on my components because I can get 100-200 watts in a decent size amp for me anyway and get usually better specs all around without having to pay a big price difference from an A/B to a D. Now if I wanted a small footprint with more output than I would use a D. To me the only advantage of the class D is the efficiency versus the A/B and thats it. So I wouldn't worry about the sq of a A/B vs D if you can fit it use an A/B if you can't go with the D.


Now that argument I can deal with 

-Matt


----------



## WLDock (Sep 27, 2005)

Seemed there were some that liked the XTANT 1.1i:
http://www.xtant.com/archives/html/products/xtant1.1i.cfm
http://www.caraudiomag.com/testreports/0308cae_xtant_11i_car_audio_amplifier/index.html
http://ampguts.realmofexcursion.com/Xtant_1.1i/










http://www.xtant.com/archives/html/news/link.cfm?article=1149

http://www.xtant.com/archives/html/products/xtantActualSize.pdf

http://www.xtant.com/archives/html/techSupport/pdfs/xtant1.1iMan.pdf

I wonder how it compares to the current crop?


----------



## aranthop (Dec 30, 2007)

Thank you so much guys on your inputs guys. Just want to recap:

1. Class D Amps won't deteriorate mid high to high frequency drivers;
2. Class D Amps may not have the consistency of an A or A/B class amp in terms of power output, but it isn't that much of an issue since it's hardly noticeable (correct me if I'm wrong on this one please);
3. Class D amps are more energy efficient than the others;
4. Class D amps are cooler to operate;
5. Class D amps today is far much better than those released 5 years ago....


Guys lemme know if I missed anything.


----------



## michaelsil1 (May 24, 2007)

aranthop said:


> 4. Class D amps are cooler to operate.


The Alpine PDX 4.150 I had got pretty hot (well vented) under load.


----------



## WRX/Z28 (Feb 21, 2008)

89grand said:


> Besides that, what are the differences between the two amps distortion specs, like .01% vs .08%?
> 
> If you can hear that difference, it must be torture just listening to music.


Does anyone realize that a THD (total harmonic distortion) spec is not distortion in the manner that it's introducing noise or static into your signal? All THD measures is how different the signal coming out of the amp is from the signal coming in. You cannot hear this distortion since you can't compare it to the original signal. Why do you think tube amps have such high THD %? The same reason they are said to have a "warm" sound to them. They alter the signal. Do they sound bad? Do they have all sorts of static and noise? No. THD is a horrible spec to compare amplifiers against. It literally means nothing. It is not a distortion rating in the sense of how clean the amp is. The better rating for that would be Signal to Noise, but even that's not a great way to compare. Really, you just need to listen to them, and trust a good amp designer. My oppinion is that I haven't heard a good sounding amp from a japanese manufacturer. I still don't get why everyone is crazy about the PDX's, and I can only attribute it to size. They really don't sound like anything special. They don't sound terrible, but not worth all the hype. Keep in mind this is just my oppinion, and oppinions vary. 

The problem inherent in class d amps is that they don't produce high frequency's well enough. Alot of you will argue that humans can't generally hear much above 18k, but the fact of the matter is, frequency's above 18k will interact with and affect frequencys below 18k, and although you may not "hear" them, you still hear their effects. This is why most class d amps seem to be missing something on highs, and you usually can't put your finger on why they aren't as pleasant to listen to. They aren't bad if you're system isn't up to the task of producing frequency's above 18k anyway, but for those of us with setups that go to 20k or above, they are a limitation. 

This being said, i'll stick to class A/B for highs. I'll probably even stick to them for subs. For the guy with the small alternator in his honda, who cares about volume more than sq, the class d is a great choice. They're efficient, small, and run cold, and they don't sound terrible. They just miss that something that makes an amp exceptional.


----------



## 89grand (Nov 23, 2006)

WRX/Z28 said:


> I still don't get why everyone is crazy about the PDX's, and I can only attribute it to size. They really don't sound like anything special. They don't sound terrible, but not worth all the hype. Keep in mind this is just my oppinion, and oppinions vary.


I already addressed that earlier. The "hype" has nothing to do with their sound, it's about their size, power and efficiency.
I never heard anyone say that they sounded better than any other amp.



WRX/Z28 said:


> The problem inherent in class d amps is that they don't produce high frequency's well enough. Alot of you will argue that humans can't generally hear much above 18k, but the fact of the matter is, frequency's above 18k will interact with and affect frequencys below 18k, and although you may not "hear" them, you still hear their effects. This is why most class d amps seem to be missing something on highs, and you usually can't put your finger on why they aren't as pleasant to listen to. They aren't bad if you're system isn't up to the task of producing frequency's above 18k anyway, but for those of us with setups that go to 20k or above, they are a limitation.


I'm not sure I buy that. Besides, how much music has any content at 18k or above.


----------



## WRX/Z28 (Feb 21, 2008)

89grand said:


> I already addressed that earlier. The "hype" has nothing to do with their sound, it's about their size, power and efficiency.
> I never heard anyone say that they sounded better than any other amp.
> 
> I'm not sure I buy that. Besides, how much music has any content at 18k or above.


I might have missed that, I replied only halfway through the thread. Sorry bout that, just caught some people talking about THD and had to explain that THD is not distortion in the same sense of the word that most people think it is. 

It's fact that frequencys above 18k still affect those below 18k. Think of droping a stone in a pond, the little waves still affect the big waves when they come in contact, even if it's a small amount. Music does have content above 18k, hence the reason they release SACD and DVD-Audio. Cymbal crashes and such can get that high among other things.


----------



## St. Dark (Mar 19, 2008)

michaelsil1 said:


> The Alpine PDX 4.150 I had got pretty hot (well vented) under load.



Probably because it's SOOO small. You still have an inherent efficiency, and therefore "coolness" (for lack of a better term close to hand!) for a given size. They just made them really small, so they do get warm. Not had a problem with them thermaling, though.


----------



## St. Dark (Mar 19, 2008)

From what I recall, going waaaay back to those Infinity digital amps back in the late 80's I think... you would get slight increases or roll-offs in very top end as you deviated from a 4ohm load.

Quite a bit later, with the Xtant and Alto Mobile (RIP) full range D's, IRRC, they eliminated this by going with a much higher switching speed on the power supply. Apparently there is a correlation between this and operating frequency band (unless I have this totally wrong, which is possible...); and with higher speed power supplies getting cheaper than in the 80's we are seeing more full range D amps that don't have issues within the audio band your cat enjoys.


----------



## WRX/Z28 (Feb 21, 2008)

Part of the problem IIRC was that the class D switching noise was audible at high frequencys. IIRC the upped the switching speed again so that it was above 18k, but still had to roll the top end of the amp off more than a standard class a/b. This is going on memory from forever ago, so you may want to confirm this.


----------



## St. Dark (Mar 19, 2008)

That goes along with my memory of the Infinity amps (as told me by an Infinity rep) - there was noise that came down close enough to the top of the audio band that it was filtered to avoid IM at that top end (think sampling noise with early CD players). So there was a filter on the output stage, which was optimized for a 4ohm load. Hence the slight rise/rolloff as you hooked up different impedances.


----------



## aranthop (Dec 30, 2007)

Just another clarification again. Is the consensus saying that class D performs the same as class A/B amps for SQ?


----------



## WRX/Z28 (Feb 21, 2008)

No, just that class D isn't terrible, but has some limitations in the realm of SQ.


----------



## t3sn4f2 (Jan 3, 2007)

aranthop said:


> Just another clarification again. Is the consensus saying that class D performs the same as class A/B amps for SQ?


You are going to have to see for yourself on this one.


----------



## BTA (Nov 5, 2005)

I havnt been able to tell a difference and I've used a couple of brands of Class D's so far.


----------



## 89grand (Nov 23, 2006)

WRX/Z28 said:


> No, just that class D isn't terrible, but has some limitations in the realm of SQ.


I wouldn't say that that was the consensus, I'd say that there isn't a consensus at all.

For every person that feels like you do, there is one that feels like I do, that there is no difference.


----------



## mikey7182 (Jan 16, 2008)

I just picked up an Eclipse XA4000 running my MB Quarts bi-amped, and it sounds every bit as good, if not better than my Alpine MRV-F545 did. I want to say it puts out more power even, not to mention it runs absolutely cool. I was out just now really working it hard for about an hour and a half, and it was cool to the touch afterward. Very efficient, seems like.


----------



## MadMaxSE-L (Oct 19, 2006)

mikey7182 said:


> I just picked up an Eclipse XA4000 running my MB Quarts bi-amped, and it sounds every bit as good, if not better than my Alpine MRV-F545 did. I want to say it puts out more power even, not to mention it runs absolutely cool. I was out just now really working it hard for about an hour and a half, and it was cool to the touch afterward. Very efficient, seems like.


I love my XA's - and they play my tweeters and mids without issue


----------



## mikey7182 (Jan 16, 2008)

For sure... I'm considering getting rid of my MRD-M1005 to pick up an XA that will run my one Alpine Type X 10... do they make anything around 1000w [email protected] ohms?


----------



## mikey7182 (Jan 16, 2008)

Any idea if the XA1000s are strappable? I'd need the power @2 ohms so one amp per VC wouldn't really work, as they are 4 ohm VC each, and the 1000 isn't putting out much power at 4 ohms. I guess I could always grab another XA4000 and bridge it down to [email protected] ohms mono, as the one I have now seems to be way underrated.


----------



## MadMaxSE-L (Oct 19, 2006)

mikey7182 said:


> For sure... I'm considering getting rid of my MRD-M1005 to pick up an XA that will run my one Alpine Type X 10... do they make anything around 1000w [email protected] ohms?


I don't think Eclipse makes anything that large right now, but I know there are some of the digital Eclipse mono's out there that can do atleast 1000w rms.



mikey7182 said:


> Any idea if the XA1000s are strappable? I'd need the power @2 ohms so one amp per VC wouldn't really work, as they are 4 ohm VC each, and the 1000 isn't putting out much power at 4 ohms. I guess I could always grab another XA4000 and bridge it down to [email protected] ohms mono, as the one I have now seems to be way underrated.


I don't think any of the Eclipse amps are strapable...

As far as the bridging goes, that's what I'll be doing when I get my TC2000 - it has dual 4 ohm coils and each one will be getting 350w rms from from the XA.

-Matt


----------



## WRX/Z28 (Feb 21, 2008)

89grand said:


> I wouldn't say that that was the consensus, I'd say that there isn't a consensus at all.
> 
> For every person that feels like you do, there is one that feels like I do, that there is no difference.


Yes, but that person would be wrong. 

In all seriousness though, Class D is not as good SQ wise, this is on paper, and proven. The better question would be, can people tell the difference. I can. Would I be able to get in a car and tell you whether the amp it had was class A/B or class D? No, probably not. Have I compared the two in identical setups and found a difference? Yes, I have. In the same manner, I don't think anyone could get in my car and tell me what speakers are in it, but that doesn't mean they don't sound better than some other pairs. To each his own, but if the debate is whether Class A/B are better on paper, they are. That's a fact, not an oppinion.


----------



## MadMaxSE-L (Oct 19, 2006)

WRX/Z28 said:


> Yes, but that person would be wrong.
> 
> In all seriousness though, Class D is not as good SQ wise, this is on paper, and proven. The better question would be, can people tell the difference. I can. Would I be able to get in a car and tell you whether the amp it had was class A/B or class D? No, probably not. Have I compared the two in identical setups and found a difference? Yes, I have. In the same manner, I don't think anyone could get in my car and tell me what speakers are in it, but that doesn't mean they don't sound better than some other pairs. To each his own, but if the debate is whether Class A/B are better on paper, they are. That's a fact, not an oppinion.


While I agree there may be a difference, the question remains: Is the difference audiable? To use your speaker analogy; if driver A a could play a sound from 5-50,000hz perfectly, and another speaker B could play the same sound from 10-30,000hz perfectly, driver A looks better on paper, but there would probably not be any difference that the listener could detect 

-Matt


----------



## mikey7182 (Jan 16, 2008)

Honestly, it is a tough comparison for me because I switched out components at the same time as I went from A/B to D. So I can't tell how much of the difference is the MB Quarts vs. the SPX-PROs and how much of the difference is the XA4000 vs. the MRV-F545. Needless to say it does sound 'different' but I am hearing things in the music I haven't heard before, just as I did with the SPX-PROs compared to the Boston Pro60s before them. Every speaker has its' own sound, and although some may disagree, so does every amp. In a perfect world, amps shouldn't color the sound, but this isn't a perfect world.  The same way tube amps have their own warm, colored sound, I think class D vs. class A/B have their own respective sounds. Not that either is better or worse; just different.  I personally LOVE this new XA4000. Aesthetically it is beautiful, and it really makes these QSDs work hard. I couldn't be happier with the combo.


----------



## aranthop (Dec 30, 2007)

So if any of you will choose between class D or A/B for SQ what will it be?


----------



## WRX/Z28 (Feb 21, 2008)

Being that I have yet to see anyone argue that class D amps are better for SQ, instead most just argue that they aren't noticeably worse. I'd have to say A/B. That would have been my vote regardless though.


----------



## MadMaxSE-L (Oct 19, 2006)

WRX/Z28 said:


> Being that I have yet to see anyone argue that class D amps are better for SQ, instead most just argue that they aren't noticeably worse. I'd have to say A/B. That would have been my vote regardless though.


Honestly, what sense does that make? Because no one has said that fullrange class D amps aren't worse than class A/B's, the A/B's are better???

 

I will say here and now that the fullrange Class D's *ARE *better. WHY YOU ASK?

Because they draw less power and sound just as good as the the A/B's they can replace Why _wouldn't_ they be better???

-Matt


----------



## WRX/Z28 (Feb 21, 2008)

MadMaxSE-L said:


> Honestly, what sense does that make? Because no one has said that fullrange class D amps aren't worse than class A/B's, the A/B's are better???
> 
> 
> 
> ...


Here's the problem with your statement. #1: You took my wording all wrong, I never said that was why they "are better". I said that my vote was for class A/B for sq. #2, is in this part of your sentence "sound just as good as the the A/B's they can replace". Here, you used the A/B's as the reference for sq, only stating that D's are "as good". Not citing that they are better for sq, just again stating the obvious, which is that they are more efficient. I'm really trying not to come off like a douche, but it seems like you're attacking me for choosing A/B, and being able to support why in previous posts. 

I was simply stating that I had yet to hear anyone argue that Class D was better for SQ in any way that mattered to SQ. Not efficiency, not size, not thermally. Just SQ. Can anyone make a point as to why they are better for SQ only? I'd like to hear it, honestly. I don't have a huge alt for sure... so efficiency improvements would be nice.


----------



## mikey7182 (Jan 16, 2008)

I think your last sentence hit it on the head... Assuming one ISN'T better than the other; in other words, if SQ isn't a proveable advantage of either A/B or D amps, yet one is obviously superior in terms of efficiency, I think that would be the amp I would choose. I think the only reason A/B is used as a reference, like you said, is because they have been around for so long as full range amplifiers. Class D has been around a long while too, but has not seen the widespread consumer use in full range car audio application until recently. I think if we were having this conversation in 20 years, perhaps Class D may be the new reference standard?  Who knows? As far as my personal experience, switching recently from the Alpine 545 to the Eclipse XA4000 was night and day. Granted, as I stated previously, I switched out components as well, so it is kinda hard to say, but I haven't noticed any performance DECREASE, and the damn thing is cool to the touch after 2 hours of hard work! Not to mention dimming is now nonexistent. So all around, I'd say Class FD is an all around better amp, although maybe not proveably in the SQ dept. I don't know enough about amp technology to comment fully on what I'm about to say, but I would make the assumption that an amp running cooler would help its overall performance, i.e. distortion, etc, which could contribute to better SQ. Just a thought...


----------



## 89grand (Nov 23, 2006)

aranthop said:


> So if any of you will choose between class D or A/B for SQ what will it be?


Class D, because they are way more efficient than class A/B, yet sound identical to class A/B.

Sounds like a win win situation to me.


----------



## WRX/Z28 (Feb 21, 2008)

mikey7182 said:


> I think your last sentence hit it on the head... Assuming one ISN'T better than the other; in other words, if SQ isn't a proveable advantage of either A/B or D amps, yet one is obviously superior in terms of efficiency, I think that would be the amp I would choose. I think the only reason A/B is used as a reference, like you said, is because they have been around for so long as full range amplifiers. Class D has been around a long while too, but has not seen the widespread consumer use in full range car audio application until recently. I think if we were having this conversation in 20 years, perhaps Class D may be the new reference standard?  Who knows? As far as my personal experience, switching recently from the Alpine 545 to the Eclipse XA4000 was night and day. Granted, as I stated previously, I switched out components as well, so it is kinda hard to say, but I haven't noticed any performance DECREASE, and the damn thing is cool to the touch after 2 hours of hard work! Not to mention dimming is now nonexistent. So all around, I'd say Class FD is an all around better amp, although maybe not proveably in the SQ dept. I don't know enough about amp technology to comment fully on what I'm about to say, but I would make the assumption that an amp running cooler would help its overall performance, i.e. distortion, etc, which could contribute to better SQ. Just a thought...


The dimming thing you touched on, as well as heat, might be a good argument. I wonder how a class A/B really reacts to voltage drops due to it's own current draw. I wonder if in a car with a small alternator, if that would give D a sq advantage at all. 

*edit* Also, I think the reason that full range class D are coming into "style", is simply that after alpine released the PDX, amp companies realized that size was a big selling feature and concern. They also know that "kids" are hip to the lingo of Class D, even if they don't really understand what it means. 


89grand said:


> Class D, because they are way more efficient than class A/B, yet sound identical to class A/B.
> 
> Sounds like a win win situation to me.


I still don't think that they sound identical. I don't think any one amp sounds identical to another, and I'd bet that you don't either. So how can you say they sound identical? Are you saying that the only thing that matters is the power spec on the box, and an eclipse sounds the same as an alpine? 

I still think A/B has a frequency response advantage that when all other things are equal, gives A/B the advantage. (All other things being steady power supply, heat disipation, and all other variables)


----------



## mikey7182 (Jan 16, 2008)

I think the argument there, though, is whether or not that frequency response is audible. I think that was mentioned earlier in the thread... if a class A/B has a frequency range of say 10Hz-50Khz, and a class D has a frequency range of 10Hz-25kHz, I wouldn't really say the A/B has an advantage, unless your dog is riding in the car with you  Now on the other hand, there was an article/review written on the Premier PRS amps that showed a pretty significant dropoff after around 15kHz IIRC. I'm not sure about the other Full Range Class D amps but I can tell you my Eclipse definitely doesn't lack any upper end sparkle!


----------



## 89grand (Nov 23, 2006)

WRX/Z28 said:


> I still don't think that they sound identical. I don't think any one amp sounds identical to another, and I'd bet that you don't either. So how can you say they sound identical? Are you saying that the only thing that matters is the power spec on the box, and an eclipse sounds the same as an alpine?
> 
> I still think A/B has a frequency response advantage that when all other things are equal, gives A/B the advantage. (All other things being steady power supply, heat disipation, and all other variables)


Yes, I do think nearly every amp sounds the same. It's been proven that no one can pick out a certain amp reliably in blind tests. I'm sure Eclipse amps sound the same as Alpines, since I'm sure I could never tell which amp was playing in any given system.

If your current amps were swapped out for equally powerful amps without your knowledge, whether they were class A/B or D and level matched to your current setup, you'd never know they were changed...and that to me says amps sound the same.

There is no frequency response advantage to class A/B either.


----------



## mikey7182 (Jan 16, 2008)

I don't think amps sound the same... I think in an ideal world, they would, but they don't (to me). For example, in home audio, tube amps are known for their "sonic signature." More applicable, though, with the same HU, same components, and switching out amps, I have been able to tell a difference between amps in lots of setups I've done. Now if you came and switched mine out for a different one, I more than likely wouldn't be able to say "Hey! That sounds like you swapped out my XA4000 for a _______!" But I would be able to tell that it sounded different. And assuming you left everything else the same, including not just other equipment, but EQ, TA, etc, I would have to assume it was the amp. Whether an amps' individual sonic signature has to do with the quality of products used during the manufacturing process, efficiency, or whatever, I'm not sure. But I can say that I have heard the difference, whatever causes it.


----------



## 89grand (Nov 23, 2006)

I really don't believe you could tell your amps were changed.

If you could, you either have to have real ****ty amps and they were replace with good ones, or if you'd have to have good amps that were replaced with ****ty amps that altered the sound enough to tell.

Any decent amp should have no sound to it at all, it should simply amplify the signal and do nothing more. Not talking about tubes vs solid state, but car amps.

Even then though, I'm not sure how many people could tell if there were listening to tubes or solid state in the home either.

Do you think you could pick out which amp was playing between two different amps that were being switched back and forth?

Recently there was a post of a test with several different home amps, including $6k mono blocks, semi high end amps and a Pioneer receiver and no one on the panel could pick the amps with any regularity...and that's even between the $6K mono blocks and a Pioneer receiver. I doubt car amps have any greater difference than those two amps do.

In fact, it was on page 2:

http://bruce.coppola.name/audio/Amp_Sound.pdf


----------



## WRX/Z28 (Feb 21, 2008)

mikey7182 said:


> I think the argument there, though, is whether or not that frequency response is audible. I think that was mentioned earlier in the thread... if a class A/B has a frequency range of say 10Hz-50Khz, and a class D has a frequency range of 10Hz-25kHz, I wouldn't really say the A/B has an advantage, unless your dog is riding in the car with you  Now on the other hand, there was an article/review written on the Premier PRS amps that showed a pretty significant dropoff after around 15kHz IIRC. I'm not sure about the other Full Range Class D amps but I can tell you my Eclipse definitely doesn't lack any upper end sparkle!


What I brought to light earlier in this thread, is that even if 25k isn't audible, the effects 20k+ have on frequencys 20k and down is. You may not hear the frequency, but you hear the interaction those frequencys have with what's under them. Why do you think SACD and DVD-Audio have such high frequency ranges? Wouldn't CD have been enough? Your ears are the most sensitive piece of equipment you own. Trust me, you'll hear a difference. I know the eclipses don't sound "bad", I have them on my sound boards too, but they lack something the TRU's have. They are about 1/3 the price though...


89grand said:


> Yes, I do think nearly every amp sounds the same. It's been proven that no one can pick out a certain amp reliably in blind tests. I'm sure Eclipse amps sound the same as Alpines, since I'm sure I could never tell which amp was playing in any given system.
> 
> If your current amps were swapped out for equally powerful amps without your knowledge, whether they were class A/B or D and level matched to your current setup, you'd never know they were changed...and that to me says amps sound the same.
> 
> There is no frequency response advantage to class A/B either.


I would definately be able to tell. I can tell on a sound board in my store after I level match. I have recently replaced a JBL 4 channel with a TRU Billet 475. The TRU is rated less, but is definately much more open up top, and way punchier and ballsier in the bass dept. 

If you really believed that there was no difference, you'd own pyramid amps. You could just buy the strongest ones they make, and run them in your car and never know the difference. Next you'll tell me that all CD players sound the same too, and that cables make no difference whatsoever. 

Your last statement is factually wrong. Find me a class D rated to play over 20k. I doubt you can. There's a reason. They bumped the switching noise up just over the 20k threshold. That's why they roll off above that point, so you don't hear the switching. Trust me, even at 20k+, you'd hear it. 
Well designed class A/B's generally can play well above that point. That's why I own more than a few amps rated up to 30k +/- 3db that are class A/B. 


Has noone noticed the LOW S/N ratios on all the new class D's? How about the high THD%?


----------



## WRX/Z28 (Feb 21, 2008)

89grand said:


> I really don't believe you could tell your amps were changed.
> 
> If you could, you either have to have real ****ty amps and they were replace with good ones, or if you'd have to have good amps that were replaced with ****ty amps that altered the sound enough to tell.
> 
> ...



I have. We level matched with a DB meter in one of the sound rooms at my last employer. I listened to merely a change from Yamaha to Denon. Same price range and everything. All tone controls at 0. The denon sounded noticeably heavier in the low end, and the yamaha sounded more open up top. Nothing else changed but the amp.

*edit* I wonder who was on the panel, and if they could pick out the difference's in speakers! lol


----------



## 89grand (Nov 23, 2006)

Yeah, I will tell you that all but the ****tiest CD players sound the same or at least very very close, same thing with cables. If you could tell, you'd of won Richard Clark's amp challenge by now. 

I run brand names amps because of several things, warranty issues, reliability and resale value. I don't pick amps based on their sound, because if they alter the sound, they are ****ty amps. I picked the PDX amps because of their power output, size and efficieny, not because they sound a certain way.

Also, I don't need an amp that extends beyond 20khz, for several reasons. 1. No music has content beyond that, and 2, I can't hear beyond that anyway.

I have PPI Art series amps in my Jeep, and had JBL GTO's in my other car. I couldn't tell a difference.


----------



## 89grand (Nov 23, 2006)

WRX/Z28 said:


> I have. We level matched with a DB meter in one of the sound rooms at my last employer. I listened to merely a change from Yamaha to Denon. Same price range and everything. All tone controls at 0. The denon sounded noticeably heavier in the low end, and the yamaha sounded more open up top. Nothing else changed but the amp.
> 
> *edit* I wonder who was on the panel, and if they could pick out the difference's in speakers! lol


That doesn't count. Knowing things changed, then saying you could tell is not a fair test. A fair test would be being able to pick the Denon from the Yamaha as they were being switched back and forth as you were blind folded, with a variety of music and or movies or whatever.

The panel was made up of people that claimed to be able to tell the difference between amps.


----------



## ca90ss (Jul 2, 2005)

WRX/Z28 said:


> Your last statement is factually wrong. Find me a class D rated to play over 20k. I doubt you can.



http://www.caraudiomag.com/testreports/0308cae_xtant_11i_car_audio_amplifier/index.html


> The frequency response was an astounding 3Hz to 34kHz at -1dB


----------



## WRX/Z28 (Feb 21, 2008)

89grand said:


> Yeah, I will tell you that all but the ****tiest CD players sound the same or at least very very close, same thing with cables. If you could tell, you'd of won Richard Clark's amp challenge by now.
> 
> I run brand names amps because of several things, warranty issues, reliability and resale value. I don't pick amps based on their sound, because if they alter the sound, they are ****ty amps. I picked the PDX amps because of their power output, size and efficieny, not because they sound a certain way.
> 
> Also, I don't need an amp that extends beyond 20khz, for several reasons. 1. No music has content beyond that, and 2, I can't hear beyond that anyway.


If you go back to post #83, I already wrote why frequency's beyond 20k are important. Also, cymbal crashes and such, as well as other things in music extend past 20k. 

Richard Clark has some odd rules in that contest, including no test tones. Why not? "and if the amplifier still exhibits nonlinear frequency response, an equalizer will be set by Richard Clark and inserted inline with one of the amps so that they both exhibit identical frequency response" so if the amp sounds different, an eq will be brought in to the mix to "fix" that. lol

So he intends to defeat the sonic signature of the amp to prove it sounds the same. Sounds odd right? 

I dunno, years of listening tells me that amps don't all sounds alike. Ask any tube amp guy. You stated earlier that any amps that add anything to the singal are ****ty. Better let those tube amp guys know they all listen to ****ty amps. 

BTW, i'm glad this debate hasn't been taken personally. It's all in good fun, and to each his own.


----------



## 89grand (Nov 23, 2006)

Quote from CA&E's test of the PDX-4.150

_"Alpine conservatively states the frequency response to be 20Hz to 20kHz, but I measured it to be 5Hz to 32kHz at -1dB, very impressive for a Class D amplifier."_

Source:
http://www.caraudiomag.com/0607_cae_alpine_pdx_4150_amplifier/index2.html

But like I said, none of us can hear beyond 20khz anyway, and most of us, not even up to 20khz. Seems a mute point really considering that.


----------



## WRX/Z28 (Feb 21, 2008)

Funny how CA&E can claim more than the manufacturers. Maybe they should have wrote the manuals. lol. Somehow, I think if Alpine and Xtant's Class D's went that high, they'd be the first to tell you, not a biased mag that needs to write a story people want to hear. 

Yet again, i'll repeat myself. Frequencys above 20k, will still interact with, and affect frequency's below 20k. This is why even though 22k+ is inaudible to most humans, it still matters.


----------



## 89grand (Nov 23, 2006)

WRX/Z28 said:


> Funny how CA&E can claim more than the manufacturers. Maybe they should have wrote the manuals. lol. Somehow, I think if Alpine and Xtant's Class D's went that high, they'd be the first to tell you, not a biased mag that needs to write a story people want to hear.


So now CA&E is biased?

How do you figure that? How many amps have we all seen that were under rated output wise by the manufacturer, quite a few right? Isn't it the same thing, wouldn't the manufacturers be the first to tell us that there amps were more powerful than they are rated for?

Alpine probably saw no need to rate frequency response above the threshold of human hearing.


----------



## ca90ss (Jul 2, 2005)

WRX/Z28 said:


> Funny how CA&E can claim more than the manufacturers. Maybe they should have wrote the manuals. lol. Somehow, I think if Alpine and Xtant's Class D's went that high, they'd be the first to tell you, not a biased mag that needs to write a story people want to hear.



Try to find one amp that when measured meets factory specs exactly.


----------



## WRX/Z28 (Feb 21, 2008)

89grand said:


> So now CA&E is biased?
> 
> How do you figure that? How many amps have we all seen that were under rated output wise by the manufacturer, quite a few right? Isn't it the same thing, wouldn't the manufacturers be the first to tell us that there amps were more powerful than they are rated for?
> 
> Alpine probably saw no need to rate frequency response above the threshold of human hearing.


Magazine guys, biased? Naw... couldn't be. 

Weird that Alpine would rate their speakers above human hearing by quite a bit, but not their amps. lol 

http://www.alpine-usa.com/US-en/products/product.php?model=SPX-17PRO&lang=en&tab=F

Who would need a speaker that plays to 60k? That's way way above human hearing. 

Power spec's being under-rated is usually because of possible variances in parts being used, and to avoid the one amp coming in 1 watt under the claimed output, forever banishing the company to hang it's head in shame. lol


----------



## WRX/Z28 (Feb 21, 2008)

ca90ss said:


> Try to find one amp that when measured meets factory specs exactly.


My point exactly.


----------



## ca90ss (Jul 2, 2005)

WRX/Z28 said:


> My point exactly.


So what is your point exactly? First you say that CA&E is biased because their measured specs are different than the manufacturers published specs. Then you agree that no amp will exactly meet factory specs. So Which one is it?


----------



## WRX/Z28 (Feb 21, 2008)

ca90ss said:


> So what is your point exactly? First you say that CA&E is biased because their measured specs are different than the manufacturers published specs. Then you agree that no amp will exactly meet factory specs. So Which one is it?



It's actually both. CA&E is biased, advertising dollars pay their revenue, not subscribers. They will hype almost any product. Never a bad review. I'm sure they'll test some A/B's and claim 50k response, and forget all about how they said that the Class D's response to 34k was higher than A/B's. Usably, at rated spec's, i'm sure they're closer to the 20k rating for the class D, far enough below any switching noise and the needed rolloff. 

I agree that the same amp, rolling off the same assembly line on the same day can have slightly different specs, but they still have to conform to a standard or a minimum spec. No two are identical. Proven by all the people going through boxes with Birthsheets in some amps, looking for the one rated highest. Like a 10 watt difference is audible on a 1000watt sub amp. 

Sorry if I wasn't clear about that. I know it was a quick reply.

I don't tend to trust magazines all the time, (I will admit that when they test something I like and give it a favorable review, I read it front to back) I've listened to PDX's, and Eclipse Class D's. I can personally say I heard a difference. Psychoacoustics? I guess anythings possible, but somehow, I don't think so.


----------



## ZoNtO (Sep 20, 2005)

So what was your opinion of the PDX line compared to the others then? I ask cuz I have a PDX5 on hold right now I was planning to pick up in a couple days.


----------



## WRX/Z28 (Feb 21, 2008)

ZoNtO said:


> So what was your opinion of the PDX line compared to the others then? I ask cuz I have a PDX5 on hold right now I was planning to pick up in a couple days.


My oppinon was that they were great for size, and efficiency. I didn't think they sounded any better than most mid level amps I heard. If size isn't an issue for you, but you want better efficiency, i'd look at eclipse's class D's.

If you trust my oppinion regarding SQ differences. I'd look at a TRU steel series amp. They're in the same price range as the PDX's, and I think they sound better. Oppinions will vary though.


----------



## ca90ss (Jul 2, 2005)

WRX/Z28 said:


> I don't tend to trust magazines all the time, (I will admit that when they test something I like and give it a favorable review, I read it front to back)


So you only trust them when they agree with you and when they disagree they're biased.



> Psychoacoustics?


Not necessarily, I'd be more inclined to question your testing methods.


----------



## WRX/Z28 (Feb 21, 2008)

ca90ss said:


> So you only trust them when they agree with you and when they disagree they're biased.
> 
> Not necessarily, I'd be more inclined to question your testing methods.


No, I said I read the whole article, not that I trust them. It's funny that they don't always note the flaws in the products that I notice, even being a guy that likes the product. 

and why my testing methods? I use my ears, and a pretty quiet room. In the case of TRU vs. JBL vs. Eclipse, I used the same room, same deck, same speakers. I don't know how many more variables I can get rid of.


----------



## ca90ss (Jul 2, 2005)

WRX/Z28 said:


> No, I said I read the whole article, not that I trust them. It's funny that they don't always note the flaws in the products that I notice, even being a guy that likes the product.


Fair enough.



> and why my testing methods? I use my ears, and a pretty quiet room. In the case of TRU vs. JBL vs. Eclipse, I used the same room, same deck, same speakers. I don't know how many more variables I can get rid of.


As has been mentioned previously a blind A/B/X with gains matched crossovers and any signal processing defeated and below clipping is the only fair way to compare. It's not exactly fair when you know which amp is playing. That's when psycho-acoustics comes into play.


----------



## WRX/Z28 (Feb 21, 2008)

ca90ss said:


> Fair enough.
> 
> 
> As has been mentioned previously a blind A/B/X with gains matched crossovers and any signal processing defeated and below clipping is the only fair way to compare. It's not exactly fair when you know which amp is playing. That's when psycho-acoustics comes into play.


Do I have to EQ them identically too to eliminate the variances between the amps? lol. 

I never said class D were terrible, but when someone was asking whether Class A/B has SQ benefits over D, I have to say IMO yes.


----------



## stereojnky (Mar 17, 2008)

It's also not true that they (CA&E) favorably rate all products. They didn't give Dynaudio or MB Quart Q's good reviews. I thought the same thing before I read these two reviews.
http://www.caraudiomag.com/testreports/0608_cae_mb_quart_qsd216_component_set/index.html
http://www.caraudiomag.com/testrepo...40mk2_car_loudspeakers/dynaudio_speakers.html
Again they weren't brutal but they were honest. Especially with two of the most respected names in car audio.


----------



## jp88 (Jun 25, 2007)

All this talk about over 20k any sounds over 20k are a moot point unless you have a dvd or sacd in your car. Cd audio is cut off at 20k


----------



## aranthop (Dec 30, 2007)

Given what everyone has contributed, my deepest of gratitude extended to all who contributed, with SQ in mind, class d is definitely has grounds to hold. Class D, on record has shone in mid bass and subwoofer channels. But can there be much difference in highs if compared to hybrid tube amps?


----------



## aboof (Jul 6, 2008)

WRX/Z28 said:


> Do I have to EQ them identically too to eliminate the variances between the amps? lol.


I'm a newb to all this, and certainly not even close to an audiophile (I've used _telephone wire_ as speaker cable and had no complaints, when I was a teenager), but if I can EQ the small, cheap, efficient FD to the point that it sounds identical to the larger, more expensive, less-efficient A/B, then can someone remind me why I'd want to buy the A/B? That is, unless you're saying that the FD's un-EQd output sounds 'worse' than the A/B's, and that we're just EQing the A/B until it sounds equally 'bad.' But assuming that we have a target FR curve that we'd like to hear, and assuming that we can EQ either amp to match it within inaudible tolerances, why would I buy the A/B, all other variables being equal (e.g., build quality, additional features, etc), but with the FD being smaller and requiring less power.

I don't know anything about this Richard Clark amp challenge, and I've never even heard of Richard Clark, but the restrictions you mentioned seem reasonable to me, if the test is about real-world perception. Who listens to test tones for enjoyment or cares about which amp does a 'better' job with them?


----------



## Horsemanwill (Jun 1, 2008)

MadMaxSE-L said:


> I am running the Eclipse XA4000 amps on my subs and on my tweeters/mids at the moment - sounds fantastic (limited by tuning currently...). They are considered "full range" class D amps.
> 
> PROS:
> - lower power consumption
> ...


before i switched to iD Q amps all my amps where the Eclipse XA and EA lines. i had 2 XA1000 for the subs one XA2000 for my mids and a Ea2000 on the horns and it sounded wonderful.


----------



## WRX/Z28 (Feb 21, 2008)

aboof said:


> I'm a newb to all this, and certainly not even close to an audiophile (I've used _telephone wire_ as speaker cable and had no complaints, when I was a teenager), but if I can EQ the small, cheap, efficient FD to the point that it sounds identical to the larger, more expensive, less-efficient A/B, then can someone remind me why I'd want to buy the A/B? That is, unless you're saying that the FD's un-EQd output sounds 'worse' than the A/B's, and that we're just EQing the A/B until it sounds equally 'bad.' But assuming that we have a target FR curve that we'd like to hear, and assuming that we can EQ either amp to match it within inaudible tolerances, why would I buy the A/B, all other variables being equal (e.g., build quality, additional features, etc), but with the FD being smaller and requiring less power.
> 
> I don't know anything about this Richard Clark amp challenge, and I've never even heard of Richard Clark, but the restrictions you mentioned seem reasonable to me, if the test is about real-world perception. Who listens to test tones for enjoyment or cares about which amp does a 'better' job with them?



You won't hear the difference. If you've used telephone wire as speaker cable, you should go ahead and buy the class D. Ton's of people here will assure you there are no SQ differences anyway.


----------



## aboof (Jul 6, 2008)

WRX/Z28 said:


> You won't hear the difference. If you've used telephone wire as speaker cable, you should go ahead and buy the class D. Ton's of people here will assure you there are no SQ differences anyway.


I used the telephone wire example as a joke and to kind of set the stage for how ignorant I am on these topics in general, but yes I did honestly use telephone wire as speaker cable (in my first apartment) and didn't really notice anything wrong, but I was also using speakers I found on the curb 

I suspect I might be able to hear telephone wire today with working speakers (I mean, really, telephone wire), but I severely doubt I could tell hardware store speaker wire from anything more expensive. Either way, yes, I'm sure _I_ couldn't hear a difference between a good A/B and a good FD, but the rest of my post wasn't supposed to be about me specifically, but rather asking the question, 'if you can take the A/B, EQ it to sound as good as you like, and then you can take the FD, and EQ it to sound the same, why would you buy the A/B, everything else being equal, except size, cost, and efficiency?' I know it was confusing since I used "I" throughout the post. I was kind of asking if you were saying that you hold that the A/B has sound quality advantages over the FD that cannot be resolved with an EQ, which I guess you are saying it does. I'm just interested from a theoretical perspective, since, as already established, I am pretty certain there's no way I could personally hear the difference.


----------



## ca90ss (Jul 2, 2005)

WRX/Z28 said:


> Ton's of people here will assure you there are no SQ differences anyway.


And they're right. Unless someone can provide objective evidence to the contrary.


----------



## JimJ[VT] (Mar 18, 2006)

I've always thought of it as "all amps that measure the same, sound the same". Thing is, not all amps measure the same 

When I sit down at home to critically listen to things, it's on the Class A SET monos...


----------



## WRX/Z28 (Feb 21, 2008)

ca90ss said:


> And they're right. Unless someone can provide objective evidence to the contrary.


exactly!


----------



## dingaling (Apr 14, 2005)

I've used a couple of full range switchin amps like Alpine PDX. You can definitely hear a difference between them and some nicer a/b amps. I'm doing an amp comparison right now and if anyone would like to bring their digital amp to my place, i'll gladly host a comparison. Right now, i have a Tru C7, TRU ss44?, Audison Vrx2 4.300, Mcintosh mcc602tm + Mc4000m, Audison VR209, Abyss 4aa, zapco c2k 2.5, RF Power T8004, Pioneer PRS x340 and I believe a Tru Billet should be coming. From what i remember of my PDX listening. It was definitely not a bad amp, but lacked the width and transparency of the nicer amps. Vocals sounded distant, not as upfront, and topend was definitely a lil bit subdued compared to others. Bass was definitely strong though, although I didn't have a very low Fr driver to test sub bass on.


----------



## SSSnake (Mar 8, 2007)

WRX/Z28,

Wrong on sooooo many counts but with conviction!

First THD is a spec of merit for amps and has been for some time. If the amp is decent you will likely never hear differences in the THD of two amps because the THD of the speaker system is typically MUCH higher.

SNR is definitely a spec of merit (on this we can agree) however the noise floor you typically have problems with inside a car comes from the input signal and the amps inability to succesfully reject noise (I wish every manufacturer would go to diferential I/O or opticcal).

Signals above 20khz DO NOT AFFECT signals below 20khz. Look into fourier transforms to understand. Your ears are essentially bandpass devices. They like electronic filters have a slope associated with them. However, once below the threshold of audibility the listener does not hear them. They may feel them or see their affects but they do not hear any difference.

Your reference to chaning amps and hearing the difference... Did you ensure that the frequency response of the two amps was the same? If so, how? My guess is that what you heard was a frequency response difference in the two amps. These do exist and are audible. However, they are very easy to correct as well.


----------



## dingaling (Apr 14, 2005)

SSSnake said:


> WRX/Z28,
> 
> 
> Your reference to chaning amps and hearing the difference... Did you ensure that the frequency response of the two amps was the same? If so, how? My guess is that what you heard was a frequency response difference in the two amps. These do exist and are audible. However, they are very easy to correct as well.


how do you correct imaging width?


----------



## MIAaron (May 10, 2005)

dingaling said:


> I've used a couple of full range switchin amps like Alpine PDX. You can definitely hear a difference between them and some nicer a/b amps. I'm doing an amp comparison right now and if anyone would like to bring their digital amp to my place, i'll gladly host a comparison. Right now, i have a Tru C7, TRU ss44?, Audison Vrx2 4.300, Mcintosh mcc602tm + Mc4000m, Audison VR209, Abyss 4aa, zapco c2k 2.5, RF Power T8004, Pioneer PRS x340 and I believe a Tru Billet should be coming. From what i remember of my PDX listening. It was definitely not a bad amp, but lacked the width and transparency of the nicer amps. Vocals sounded distant, not as upfront, and topend was definitely a lil bit subdued compared to others. Bass was definitely strong though, although I didn't have a very low Fr driver to test sub bass on.


Since this a Class D thread, I gotta ask if you have heard the new JL hd600/4 or 750/1.


----------



## WRX/Z28 (Feb 21, 2008)

SSSnake said:


> WRX/Z28,
> 
> Wrong on sooooo many counts but with conviction!
> 
> ...


SSSNake Wrong on so many counts yourself, but oblivious to it. 

Signals above 20k absolutely interact with those below 20k, this is the nature of sound, all freqencys can interact with each other. Think of ripples in a pool. Small waves can interact with large ones, and cause peaks and dips. Sound is no different. I'm not arguing that most people can hear above 20k, although some can, it's rare, and that wasn't my point anyway. My point was the interaction sound above 20k has with sound below 20k. 

THD Has absolutely no merit. You can't hear the difference in THD, and THD is not what most people beleive it is. People seem to think this is a distortion spec in the sense that you will hear some hiss, or background noise, or some other noticeable difference. WRONG, THD is the percentage of variation from input signal to output signal. It could be above 1%, and if you didn't have the original signal to compare it to, you might not notice. Below 1% is inaudible even with the original to compare to. 

Frequency response. I'd love to hear how you beleive frequency response can be corrected. Forget the fact that all amps I compared are said by the manufacturer to be flat from 20hz-20khz +/- 3db. 

How did I get dragged back into this. I already gave up and said you won't hear a difference. That doesn't mean I don't.


----------



## michaelsil1 (May 24, 2007)

WRX/Z28 said:


> How did I get dragged back into this. I already gave up and said you won't hear a difference. That doesn't mean I don't.


I gave up; I also hear a difference.


----------



## capnxtreme (Feb 5, 2008)

> Signals above 20k absolutely interact with those below 20k, this is the nature of sound, all freqencys can interact with each other. Think of ripples in a pool. Small waves can interact with large ones, and cause peaks and dips. Sound is no different. I'm not arguing that most people can hear above 20k, although some can, it's rare, and that wasn't my point anyway. My point was the interaction sound above 20k has with sound below 20k.


And your point is incorrect. The resultant sum wave will contain higher frequency components "layered" upon the lower frequencies, but those components of the signal don't "interact" with the other frequencies in the way that you are implying they do.

Ripples in a pool are a misleading analogy. It would be an accurate analogy if there are high frequency ripples that we can't see. The high frequency ripples would "interact" with the ripples we can see, but we would still just see that component which we can see, and it would look the same as before.

Ever used DSL? 



> Frequency response. I'd love to hear how you beleive frequency response can be corrected.


Um, EQ?


----------



## WRX/Z28 (Feb 21, 2008)

capnxtreme said:


> And your point is incorrect. The resultant sum wave will contain higher frequency components "layered" upon the lower frequencies, but those components of the signal don't "interact" with the other frequencies in the way that you are implying they do. Ripples in a pool are not a good analogy.
> 
> 
> 
> Um, EQ?


I beleive he was speaking about range, not flatness. Possibly referring to the fact that some class D's roll off the top end of the range. I think I did specify in that same post that the amp's response was 20-20k +/- 3db. Was I not clear?

Also, waves in a pool function the same way sound waves do, just in a visible way. Again, see my earlier posts for a explanation on how waves above 20k still interact with those below 20k. It's a fact. The only argument could be that they don't have a ton of impact, but the interaction is still there, right down to how they interact with panels in your car, and transfer to small amounts of heat once absorbed. Ever adjust an eq up on one band, only to see a suckout on the band below?


----------



## [email protected] (Jun 12, 2008)

i just look to the guys that compete in sq, you wont see one runnign class d on components, you prob be hard pressed to find one running it on their subs, now if class d had the same sq of class AB then they would be using them


----------



## WRX/Z28 (Feb 21, 2008)

BeatsDownLow said:


> i just look to the guys that compete in sq, you wont see one runnign class d on components, you prob be hard pressed to find one running it on their subs, now if class d had the same sq of class AB then they would be using them


That's generally a pretty good indicator, although I don't see a lot of competitors using DIY drivers either, so take that for what's it's worth.


----------



## dingaling (Apr 14, 2005)

MIAaron said:


> Since this a Class D thread, I gotta ask if you have heard the new JL hd600/4 or 750/1.


I haven't personally, but if somone would like to loan me one, that would be awesome...
I liked their older 300/4 amps...


----------



## snaimpally (Mar 5, 2008)

Anyone used Avionixx amps? They use class T (tripath) which is a variation on Class D from what I gather. The variation is that the signal is kept analog. They have pretty good power output for a relatively small amp at very decent prices.


----------



## capnxtreme (Feb 5, 2008)

WRX/Z28 said:


> I beleive he was speaking about range, not flatness. Possibly referring to the fact that some class D's roll off the top end of the range. I think I did specify in that same post that the amp's response was 20-20k +/- 3db. Was I not clear?
> 
> Also, waves in a pool function the same way sound waves do, just in a visible way. Again, see my earlier posts for a explanation on how waves above 20k still interact with those below 20k. It's a fact. The only argument could be that they don't have a ton of impact, but the interaction is still there, right down to how they interact with panels in your car, and transfer to small amounts of heat once absorbed. Ever adjust an eq up on one band, only to see a suckout on the band below?


That's clearly NOT what he meant by frequency response.

I understand the concept of waves, thanks (and frequency response, you should look it up). It should be clear from my post, which you should reread.

"It's a fact" that the waves "interact," which you can see by analyzing the waveform. **golf clap** But you don't hear inaudible frequencies. It's pretty simple.

I would bet money that any EQ effect you have witnessed like that is due to an engineering tradeoff/drawback in the electronics of the EQ, and not magical frequency-shifting panel resonances.


----------



## 89grand (Nov 23, 2006)

BeatsDownLow said:


> i just look to the guys that compete in sq, you wont see one runnign class d on components, you prob be hard pressed to find one running it on their subs, now if class d had the same sq of class AB then they would be using them


Well, then no one should be using drivers from Dayton, SEAS, Peerless, Tang Band etc if "what the competitors" use is what we should using.


----------



## WRX/Z28 (Feb 21, 2008)

capnxtreme said:


> That's clearly NOT what he meant by frequency response.
> 
> I understand the concept of waves, thanks. It should be clear from my post, which you should reread.
> 
> Yes, they "interact," which you can see by analyzing the waveform. But you don't hear inaudible frequencies. It's pretty simple.


Hey, I figured if you were going to read my post and assume that I had no understanding (the eq comment) I'd do the same. 

Also, I don't think it was clear that was not what he meant. 

I agree you don't hear above 20k, but you hear what they do to below 20k, that's my point. The original question is "Are Class A/B better for SQ?" The answer is yes or no. Not "Yes, but it's not that noticeable"


----------



## capnxtreme (Feb 5, 2008)

WRX/Z28 said:


> Hey, I figured if you were going to read my post and assume that I had no understanding (the eq comment) I'd do the same.
> 
> Also, I don't think it was clear that was not what he meant.


That's what frequency response means.



> I agree you don't hear above 20k, but you hear what they do to below 20k, that's my point. The original question is "Are Class A/B better for SQ?" The answer is yes or no. Not "Yes, but it's not that noticeable"


I know that's your point. And it's wrong. What do the high frequencies "do" to the lower frequencies, exactly? I'll tell you: they add a high-frequency component to the waveform. And guess what--that high frequency component has the same frequency as the high frequency, and you CANNOT hear it.

I think we're allowed to have discussions beyond "yes" or "no" here.


----------



## WRX/Z28 (Feb 21, 2008)

capnxtreme said:


> That's what frequency response means.


It also signify's the range an amp can play in. 



capnxtreme said:


> I know that's your point. And it's wrong. What do the high frequencies "do" to the lower frequencies, exactly? I'll tell you: they add a high-frequency component to the waveform. And guess what--that high frequency component has the same frequency as the high frequency, and you CANNOT hear it.


So you think that's the only interaction it has. Well, i'd be the first to tell you that you're wrong. You don't think frequency's can change by reflecting off a surface? If you really beleive that the only interaction is to add a 20k+ component, so be it. I'd disagree with you though, and everything i've read state's that you're wrong. 



capnxtreme said:


> I think we're allowed to have discussions beyond "yes" or "no" here.


Absolutely, but everyone seems to be arguing that "No, there's no difference because the sq difference isn't that noticeable" instead of Yes, there is a difference. It is a discussion forum after all.


----------



## capnxtreme (Feb 5, 2008)

WRX/Z28 said:


> You don't think frequency's can change by reflecting off a surface?


Since "it's a fact," no, I don't think so.

Mind sharing what you've read?


----------



## WRX/Z28 (Feb 21, 2008)

capnxtreme said:


> Since "it's a fact," no, I don't think so.
> 
> Mind sharing what you've read?


Sorry, I used the word frequency's in place of sound.

Also, I'll see what articles and books I can dig up, but i've already posted all this before. If you're just looking to argue, i'm not going to waste my time. If it's going to help you, and you might want to purchase a class A/B amp as a result, i'll provide you with everything I can find.


----------



## capnxtreme (Feb 5, 2008)

Of course sound can be affected by reflections, but that's not what we were talking about. We were talking about inaudibly-high frequencies affecting audible ones. The main reason reflections affect sound is interference. Different frequencies do not interfere.

I am a skeptic, but there have been enough folks who have said that they can hear a difference, that I am willing to believe that some people can hear a difference between Class A/B and D. I have A/B on my fronts and D on my sub.

I think that your idea of inaudible frequencies affecting audible ones is wrong. I would love to read what you're talking about, though. I feel like there must be an idea you're talking about, but you're not expressing all of it, or something.


----------



## WRX/Z28 (Feb 21, 2008)

capnxtreme said:


> Of course sound can be affected by reflections, but that's not what we were talking about. We were talking about inaudibly-high frequencies affecting audible ones. The main reason reflections affect sound is interference. Different frequencies do not interfere.
> 
> I am a skeptic, but there have been enough folks who have said that they can hear a difference, that I am willing to believe that some people can hear a difference between Class A/B and D. I have A/B on my fronts and D on my sub.
> 
> I think that your idea of inaudible frequencies affecting audible ones is wrong. I would love to read what you're talking about, though. I feel like there must be an idea you're talking about, but you're not expressing all of it, or something.


Maybe i'm not clearly explaining myself. I'll try to find my sources and explain better.


----------



## Accurate_dB (Apr 1, 2020)

Sorry for resurrecting an old thread. But my excuse is back in the day I took a time machine into the future. Why? I wanted to know how much Class D can improve and advance. I know I can't go back. 
So where are we with damping factor or output impedance, SNR, and slew rates?


----------



## dgage (Oct 1, 2013)

Accurate_dB said:


> So where are we with damping factor or output impedance, SNR, and slew rates?


You’ll still get fights between class A, A/B, D and which is better but the reality is class D is up there in most specs and in some cases better. Size and efficiency is hands down owned by class D now. I say sound quality is just as good because the specs of any good amplifier is better than the human ear can distinguish. But this is where the fights come in where some people think A or A/B are better sounding. There may be a small bit of truth to that but when the car is going down the road, I say there is now way to distinguish differences in car audio amplifiers,

But to answer your question directly, the majority of amps on the market are beyond what a human can hear for all of those parameters. Some decent car audio amps report having SNR in the 80s but having heard them, I couldn’t distinguish a difference as compared to a 100db SNR amp.


----------



## Accurate_dB (Apr 1, 2020)

Most people don't setup their system while they're driving though. It is [at setup] then and there where decision is made rather or not is it good enough for me.

And damping factor is something I always thought of as something that you feel. Like how well is the cone being controlled by the amp when things get very fast and dynamic, bass wise of course. More expensive stuff back in the day, you knew right away that it was special feeling. Zapco, PPI, Xtant, JL Slash line.


----------



## Forist (Mar 28, 2020)

aranthop said:


> Any of you using class d amps on all speakers? Pros? Cons?


No, but my understanding is you'll get a better sound for Highs and Mids with Class A & B amps opposed to Class D.


----------



## Accurate_dB (Apr 1, 2020)

Today's SPL setup reminds me of turning on a fan that blows a lot of air. And my perception of SQ setup is one where power is fast and dynamic. Maybe driving 0.5 ohm loads typical of SPL, limits the damping factor to what it is. I was hoping class D today brought cake you can eat it too; because you wouldn't have to upgrade alternator, add battery, caps, and power cables. But point taken that while class D did get better, so did the Class A and A/B.


----------



## dgage (Oct 1, 2013)

Forist said:


> No, but my understanding is you'll get a better sound for Highs and Mids with Class A & B amps opposed to Class D.


I don’t agree but plenty do. Then again, a lot of audiophiles listen with their eyes and their wallet more than their ears. I use class D for my home theater speakers and that’s all I’ll use in the car. I think class D when done right sound imperceptible to other amp topologies. And I have a $1,500 ABX component where I can blind test amps and/or speakers so I’ve actually done the testing. So I’ve tested all sorts of speakers and amps in the home, including car audio amps with a nice 12V power supply.


----------



## gijoe (Mar 25, 2008)

Forist said:


> No, but my understanding is you'll get a better sound for Highs and Mids with Class A & B amps opposed to Class D.


This hasn't really been true for more than a decade. The reason Class D wasn't good at high frequency reproduction is because the switching frequencies of the amps weren't high enough. Now, we have switching plenty fast enough to reproduce well beyond 20khz. 

I wouldn't pay for Class A/B ever again with as good as Class D is now.


----------



## Forist (Mar 28, 2020)

gijoe said:


> This hasn't really been true for more than a decade. The reason Class D wasn't good at high frequency reproduction is because the switching frequencies of the amps weren't high enough. Now, we have switching plenty fast enough to reproduce well beyond 20khz.
> 
> I wouldn't pay for Class A/B ever again with as good as Class D is now.


Your Explanation was much more Informative than "dgage". His was more sarcastic.


----------



## Mullings (Jan 31, 2016)

I don’t like to comment on subjects like these cuz after my comments the tread usually go dead or take a whole different turn leaving me to think that what I said is completely stupid or proves a point.its pretty clear that this subject should be laid to rest because everybody listens to music differently and the main difference between the topologies has nothing to do with sn, thd, fr or any specs whatsoever, list me 10 class A or AB amps with specs and flexibility as good as a jl Audio hd series amp, given a task the hd amp does it perfectly, even better than most class AB amps. Who here thinks that a hd amp is better playing mids/tweets than say a Jl Audio slash series? If you can’t hear a difference here then clearly your just a lover of sound and not music. And I only use jl here because these are really good amps, in fact on my old job hd amps are all we use on all the loud systems because of their excellent speaker control at max level and compact size, I can dig up and find multiple systems that we did with over 20 hd amps in 1 car. Are class D amps the best for SQ? Certainly not IMO but if you can’t hear a difference then hey, there’s no reason for you to buy a class AB.


----------



## dgage (Oct 1, 2013)

Forist said:


> Your Explanation was much more Informative than "dgage". His was more sarcastic.


Definitely not meant to be but that is the reality. My dad is one of those and I told him so. He bought speakers recently that looked really nice, a fancy integrated amplifier, and a fancy tube DAC. The integrated amp and DAC had polished aluminum enclosures with engraving for the inputs/outputs. I couldn’t read the engravings on the enclosure so while it looked nice, it certainly wasn’t user friendly. Nice system but I wasn’t blown away, especially for the price range that it cost.


----------



## Forist (Mar 28, 2020)

Mullings said:


> I don’t like to comment on subjects like these cuz after my comments the tread usually go dead or take a whole different turn leaving me to think that what I said is completely stupid or proves a point.its pretty clear that this subject should be laid to rest because everybody listens to music differently and the main difference between the topologies has nothing to do with sn, thd, fr or any specs whatsoever, list me 10 class A or AB amps with specs and flexibility as good as a jl Audio hd series amp, given a task the hd amp does it perfectly, even better than most class AB amps. Who here thinks that a hd amp is better playing mids/tweets than say a Jl Audio slash series? If you can’t hear a difference here then clearly your just a lover of sound and not music. And I only use jl here because these are really good amps, in fact on my old job hd amps are all we use on all the loud systems because of their excellent speaker control at max level and compact size, I can dig up and find multiple systems that we did with over 20 hd amps in 1 car. Are class D amps the best for SQ? Certainly not IMO but if you can’t hear a difference then hey, there’s no reason for you to buy a class AB.


Sounds like a JL Audio salesman.


----------



## Mullings (Jan 31, 2016)

could’ve used arc audio xdi/xdi 2 and signature series, could’ve used zapco ap and st series, it’s the same across the board, I just used the hd since it’s specs are excellent, sorry if I gave you food for thought but you can still buy your class D, in the end all they’re doing is amplifying sound


----------



## Forist (Mar 28, 2020)

Mullings said:


> could’ve used arc audio xdi/xdi 2 and signature series, could’ve used zapco ap and st series, it’s the same across the board, I just used the hd since it’s specs are excellent, sorry if I gave you food for thought but you can still buy your class D, in the end all they’re doing is amplifying sound


No, it's not me that's putting together a setup, mine was completed years ago. My Stang has a 3 amp setup.


----------



## Patriot83 (May 10, 2017)

Mullings said:


> If you can’t hear a difference here then clearly your just a lover of sound and not music.
> 
> Are class D amps the best for SQ? Certainly not IMO but if you can’t hear a difference then hey, there’s no reason for you to buy a class AB.


Awesome Mullings. Out of everything I've read and heard people say about D vs AB, these 2 statements are the best I've seen.


----------



## dgage (Oct 1, 2013)

By the way, I used to wonder if class D was inferior and fought it on the home theater side. Then I bought a DSonic M3-6100 class D with 3x1500w and 4x400w and it blew my mind. My speakers are the JTR 212HTR, which are very high performance in terms of output and detail. Surrounds are JTR Slanted 8s. I’ve also tested an amp with Hypex class D modules and from that point forward I’ve been sold on class D. 

So I would say some haven’t heard some of the better class D offerings. And the flip side of that is I haven’t heard the top class A and A/B offerings.

And then there’s the fact that how many have truly done A/B testing where the ONLY thing that changes is the amp?

Like Mullings said, this argument goes on often and I doubt anyone is ever swayed one way or the other if your mind is set. My mind is also made up that class D has the capability to be very high quality, doesn’t mean every amp is but the technology is more than good enough.


----------



## gijoe (Mar 25, 2008)

Patriot83 said:


> Awesome Mullings. Out of everything I've read and heard people say about D vs AB, these 2 statements are the best I've seen.


Those 2 statements were subjective, not objective. These statements are the best you've seen because they match your own confirmation bias. We're all vulnerable to confirmation bias, so it makes comparisons like D vs. A/B very difficult. The only way to properly compare 2 different amps (regardless of topology) is in a proper double blind test where the amps are perfectly gain matched, and the switching takes place pretty much instantaneously. 

Without a proper scientific test everyone's opinions are unreliable, including mine. The entire hi-fi world thrives off of snake oil, and taking advantage of people's biases, car audio is no different. If you want to conduct your own blind test, and if you pick a favorite amp after doing so, go with it, but I certainly wouldn't trust any other person's opinion without objective data, because the science just doesn't support the claims that so many people make about the differences they hear when swapping amps. The psychological explanation for why people "hear" the differences that they claim to hear makes a whole lot more sense. The psychological elements (biases, psycho-acoustics), do affect how we perceive music, but they aren't helpful in evaluating equipment.


----------



## dgage (Oct 1, 2013)

This is what I use to test amps and speakers. Some people are quite upset when they couldn’t pick out their speakers. 









ABX Switch Comparator


Due to high demand we have produced another run of our ABX Switch Comparator. This unit allows seamless switching of up to two preamplifiers, two power amplifiers, and three sets of speakers either with or without subwoofers. The AVA ABX Switch can be used to evaluate cables and component parts...



avahifi.com


----------



## Patriot83 (May 10, 2017)

What Mullings said is true. It's what each person hears and prefers. I personally think class D in a car makes way more sense. I've heard the JL amps. They are very nice amps but I also know most of the systems I've been most impressed with were with class AB amps. Maybe it wasn't the amps. Just how it turned out. I also don't care what class a amp is or if it's a Walmart or Brax amp as long as it sounds good and works good (reliable). I doubt I'll be buying many or any class AB car amps anymore.


----------



## Mullings (Jan 31, 2016)

That’s the thing, if your dug in with your decision then whatever you like is what you like, for me, my dad doesn’t own any electronics company so I’ll just jump on the next better piece of equipment once it’s proven better by me, I bought and still have 3 hd amps,2 Zed leviathans, one I gave away and sold the other one, 2 alpine pdx, not sure where they are, might be in the garage, 5 kenwoods not sure what the model numbers but they’re the latest ones and none of them did what I want but for the regular guy it’s just an amp. There’s no connection to the music with these amps, my best discription of a class d amp vs a class ab is the class d is like a hooker ****ing you for the money, she just wants it to be over with so she can collect and go whereas the class ab is like your girl or wife lol. When I close my eyes and lean back for a good session I don’t want to listen to and amplifier that sounds like it’s your slave and it’s working against its will if that makes any sense to anybody. Again, too bad if you can’t tell the difference, and the other problem is that you’ll never hear most of these guys cars so of course their class d is the best,I’ll be out and about this season so anyone that wants to listen to my car is more than welcome. I forgot to mention that we did a blind test with a brax mx4, sinfoni ingit and a class d that I won’t mention the brand cuz I don’t want people to start ripping it outta their cars and everyone that nick could’ve thrown in the seat would say that amp b or amp a sounds like **** compared to the other one no matter which way nick switch the orientation, switching was instant, just tap your leg to switch and even a customer that was there was able to pick out the class d so some people will never get it.


----------



## dumdum (Feb 27, 2007)

We won the championship in our teams entry in entry unlimited with a pair of five channel class d hybrid audio amplifiers 👍🏼


----------



## dumdum (Feb 27, 2007)

For me speaker placement and installation is 50%, tuning 30% and equipment 20%... get the former wrong and the latter are way, way less important, get the former right and the latter are so much easier and straight forward


----------



## Mullings (Jan 31, 2016)

Winning a competition has nothing to do with how amplifiers sounds, this is only about how people enjoy their music, the car with the best staging and imaging I’ve ever heard I’m 100% sure uses a class d amp, how I know? Because it checks all the boxes for the way class d amps sounds but soundstage is about 8” above the windshield, every left or right information is coming from 1 foot or more outside the mirrors from either front seats, ****, the owner played a track and car car drove across the soundstage and I swear I heard the car coming 10 feet outside the car, tonality in my book is on the low side but a judge would have no choice but to give the car max points in all other aspects so again this is for music lover, not sound lovers.


----------



## Rainstar (May 22, 2017)

At the end of the day if your goal was to win a competition who cares what topography an amp is. In boxing there's right handers left handers(southpaw) and people more ambidextrous, in racing front wheel drive rear wheel drive and all wheel drive have all come out first place. Sure there's pros and cons to each but conclusively nothing is Better or superior indefinitely. It's how you use what you have at the best of your abilities and go where no man has gone before.

I'm tired of reading the arguments between D vs A/AB. Sure I've made my pick in which to use but why try to change people's mind on what's the best buy.


----------

