# Question on How head units and amps affect sound quality of system



## Zachyv92 (Apr 17, 2010)

lets say i was to buy some cdt components for clear sound in my car..but at the same time i wanted to buy a low end flip out head unit for looks.. but then get a good quality amp for the speakers so they weren't running through the head unit.. would the crap head unit say clarion VZ409 (touchscreen) have an affect on the sq of the speakers even when the speakers are amped? thanks


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## azngotskills (Feb 24, 2006)

Crap out of the HU = crap into the amp = crap out of the amp = crap into the speaker = crap out of the speakers

Gross generalization of course


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## MyName (Oct 14, 2009)

Audio generaly works on the above described SISO system (**** in - **** out).

I'd say, that after the install, the head unit is the second most important part of the system. But still keep it ballanced. Ther's no use in geting the top of the line HU and than having no money for speakers and amps.


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## DS-21 (Apr 16, 2005)

There's no reason grounded in reality (unless the HU doesn't have processing that you just need, and you aren't running an external box with the needed capability) to expect that a "cheap" HU will be audibly inferior to an "expensive" one.

Choosing an HU based on looks is far more grounded in reality than expecting one to "sound" different from another.


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## fourforty (Apr 17, 2010)

this is the question that's had me lurkin and searchin here the last week. why does my new double-din avh pioneer sound significantly worse with my commercial cd's of late '60's early '70's live recordings than the jvc it replaced? well the jvc has a burr-brown processor, is that it? the pioneer, i don't know. no changes were made in regard to the speakers or amp, just the HU. there is a good reason why stuff is cheap, imo.


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## t3sn4f2 (Jan 3, 2007)

DS-21 said:


> *There's no reason grounded in reality (unless the HU doesn't have processing that you just need, and you aren't running an external box with the needed capability) to expect that a "cheap" HU will be audibly inferior to an "expensive" one.*
> 
> Choosing an HU based on looks is far more grounded in reality than expecting one to "sound" different from another.


Generally I COMPLETELY agree, but these VZ clarion units are something special. I have the VZ309 and it has a god awful amount of hiss, 75dB S/N ratio spec on the manual. I plugged its preamp outputs into my home receiver's direct headphone amp's/speaker amp's preamp inputs (-10dBV alignment) and even on volume setting 1 out of 40 on the VZ I could hear a clear hiss. This was running off a car batter sitting next to the head unit in my bedroom. 

I'm not sure right now but I think that was even with the zero bit mute circuit enable since it was worse when I switched to the AUX in source.

I would say just go off the specs and that should tell you enough info. since my head unit clearly stated a poor S/N ratio, BUT it also claimed a flat response on the DVD player and when I tested it, it had a big roll off on the top end. I though, it can't be, maybe my testing was flawed, but the AUX input is flat like it is suppose to be. Probably why Amazon had these for 75% off MSRP and was throwing in a free HD radio module.

That tells me maybe you can't rely on _these_ Clarion spec sheets (maybe even others in general if the units are cheap enough?)

The VZ409 doesn't publish a low S/N ratio on the DVD but it has a similarly low S/N ratio on the speaker level outputs..........hhhhmmmm.

Noise and measurements aside.........I have no comment.


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## Toys7505 (Jul 1, 2008)

You can get the best HU out on the market, the best amp(s) out on the market, and the best speakers & subs out on the market to reproduce sound but if your source material is CRAP - then what you hear will be CRAP as well. 

Poster above said it best, sh!t in = sh!t out......my opinion is to put more $$ into the HU and amps (these are your foundation to a system) than more $$ into speakers....reason being, if your electronics are solid and of high quality and do not introduce noise into the system, then you will have an edge and better sounding system than everyone else. Again just my opinion as this philosophy can be debated from a different angle........


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## t3sn4f2 (Jan 3, 2007)

Zachyv92 said:


> lets say i was to buy some cdt components for clear sound in my car..but at the same time i wanted to buy a low end flip out head unit for looks.. but then get a good quality amp for the speakers so they weren't running through the head unit.. would the crap head unit say clarion VZ409 (touchscreen) have an affect on the sq of the speakers even when the speakers are amped? thanks


It all *ADDS* up.


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## MarkZ (Dec 5, 2005)

Toys7505 said:


> You can get the best HU out on the market, the best amp(s) out on the market, and the best speakers & subs out on the market to reproduce sound but if your source material is CRAP - then what you hear will be CRAP as well.
> 
> Poster above said it best, sh!t in = sh!t out......my opinion is to put more $$ into the HU and amps (these are your foundation to a system) than more $$ into speakers....reason being, if your electronics are solid and of high quality and do not introduce noise into the system, then you will have an edge and better sounding system than everyone else. Again just my opinion as this philosophy can be debated from a different angle........


But your opinion doesn't make any sense.  It doesn't really matter where the crappy sound is coming from -- the HU, amp, or speakers. If it's present in the chain, at ANY point, then it's a problem.

The question people should be asking is this: how different is an expensive vs. cheap HU in comparison to the difference between expensive vs. cheap speakers. And the answer, almost always, is that the difference in speakers is much much bigger. By almost every measure, too. THD differences are much bigger for speakers, dynamic range differences are much bigger for speakers, and frequency response is much different between speakers.

And by "much different", I really mean _much_ different! Any two speakers may have FR differences of several dBs within a given band. However, two HUs are generally going to be within 1dB of each other throughout the entire audio bandwidth. And between 100-10kHz, they'll be a tiny fraction of a dB apart! Also, THD generated by speakers is typically 10-100x more than that generated by HUs. Amplifiers, and everything else electronic, follow a similar trend.

So it makes more sense to invest in the right speakers before you try to perfect your electrical signal by upgrading the source unit, amplification, etc.


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## naiku (May 28, 2008)

This is an interesting topic... I plan to keep the stock head unit in my car, mostly because I feel like a single DIN looks out of place in a double DIN hole, and because I can't afford a double DIN, where half the features I will never or rarely use (movie playback, GPS) and most of the features I want (TA, Active capability) are not available without an external processor. So I plan to keep the stock head unit, and add an external processor.

But, then I wonder if no matter what I do down the line from my stock head unit, regardless of what amplifiers or speakers I have, if it is going to sound crap, because the stock head unit is (probably) crap.

I imagine, at least from my point of view, that because I am working on a budget system (albeit with used good equipment, rather than cheap new equipment) that the sound to my ear at least will be plenty good enough, and a significant improvement over the stock "premium" system. At least that is what I am hoping!!!


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## ALL4SQ (Mar 28, 2009)

MarkZ said:


> The question people should be asking is this: how different is an expensive vs. cheap HU in comparison to the difference between expensive vs. cheap speakers. And the answer, almost always, is that the difference in speakers is much much bigger. By almost every measure, too. THD differences are much bigger for speakers, dynamic range differences are much bigger for speakers, and frequency response is much different between speakers.
> 
> And by "much different", I really mean _much_ different! Any two speakers may have FR differences of several dBs within a given band. However, two HUs are generally going to be within 1dB of each other throughout the entire audio bandwidth. And between 100-10kHz, they'll be a tiny fraction of a dB apart! Also, THD generated by speakers is typically 10-100x more than that generated by HUs. Amplifiers, and everything else electronic, follow a similar trend.
> 
> So it makes more sense to invest in the right speakers before you try to perfect your electrical signal by upgrading the source unit, amplification, etc.


Wonderful post!  Unfortunately it would take a properly setup double bind test to convince many Voodoo believers. 

I personally try to convince people to spend there time on speaker installation and tuning rather than buying $2000 CD players. It ends up being like banging my head against a wall. In the end not worth my time. 

Thanks


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## Mooble (Oct 21, 2007)

MarkZ said:


> And by "much different", I really mean _much_ different! Any two speakers may have FR differences of several dBs within a given band. However, two HUs are generally going to be within 1dB of each other throughout the entire audio bandwidth. And between 100-10kHz, they'll be a tiny fraction of a dB apart! Also, THD generated by speakers is typically 10-100x more than that generated by HUs. Amplifiers, and everything else electronic, follow a similar trend.


Ah yes, but the HU is the source of your sound. You can have the cleanest $5k amp in the world but you are amplifying those minute HU differences 100 fold. What may seem like an insignificant difference on paper becomes noticeable when amplified 100 times. The good news is that most head units over $150 are capable of a good clean signal.

Features are still the main reason to spend more on a HU, not purity of signal.


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## MarkZ (Dec 5, 2005)

Mooble said:


> Ah yes, but the HU is the source of your sound. You can have the cleanest $5k amp in the world but you are amplifying those minute HU differences 100 fold. What may seem like an insignificant difference on paper becomes noticeable when amplified 100 times. The good news is that most head units over $150 are capable of a good clean signal.
> 
> Features are still the main reason to spend more on a HU, not purity of signal.


What's being amplified 100 times? The THD? We measure THD in percentage, so 0.1% THD is still 0.1% THD after being amplified. The noise? We measure noise as a ratio of signal to noise. So, if the noise is being amplified by 100, so is the signal, leaving you with the same THD. Same with frequency response -- a _relative_ measure.

So it doesn't really matter that an amplifier is there to amplify the bad things. It amplifies the good things by the same amount.


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## DS-21 (Apr 16, 2005)

t3sn4f2 said:


> Generally I COMPLETELY agree, but these VZ clarion units are something special. I have the VZ309 and it has a god awful amount of hiss, 75dB S/N ratio spec on the manual. I plugged its preamp outputs into my home receiver's direct headphone amp's/speaker amp's preamp inputs (-10dBV alignment) and even on volume setting 1 out of 40 on the VZ I could hear a clear hiss. This was running off a car batter sitting next to the head unit in my bedroom.


Interesting. That's the kind of information the forums are useful for uncovering.

Yes, there is some gear that's just plain bad. And sometimes that bad gear comes from unexpected places.

And thanks for running your various tests and posting the results!


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## Bugflipper (Apr 16, 2010)

All stock head units are not terrible. Some are actually very good. I have one badged pioneer, but is made by jvc I believe. The sq is amazing, even with the factory speakers. I am searching to upgrade the speakers, but am in no hurry because they are not unbearable at all, just a bit stale.

Cheap is a relative term. Eclipse HU are pretty good for the money. They can still be found, but wont be around much longer( last I heard they went out of business, have not heard of anyone buying out to keep the line going). Pioneer and Kenwood also are not terrible in the low to mid $100 range. 
There are always used HU in the classified sections of these forums as well. A lot of gents want the best new thing each year. In most cases a 1-4 year old top of the line is better than a new budget hu. Hell I have a nakamichi that is 20 years old that is better than many out there today.

Good luck


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## Candisa (Sep 15, 2007)

A system can only sound as good as the weakest part of it.

Good sound starts with a good headunit, if the headunit isn't good to start with, you can never get a good sound out of the speakers...

Same goes for the amplifiers, if the headunit is great, but the amps aren't, the great sound quality of the headunit will never reach the speakers...

Apart from great sound quality, every chain in the system has also its own sound. For example: some Audison, Kenwood, Audio-System... amplifiers tend to make the sound "warmer", so they change the sound a little, but this isn't always a bad thing, it can be great to tame aggressive/harsh sounding speakers.

Personally, I like to keep the signal as pure and unmodified as possible. That requires a very good headunit so there is very little distortion and noise added to the signal (I use a 13 year old top-of-the-line Panasonic radio-dcc-player + cd-changer), and great, neutral amplifiers so these also don't add much noise, distortion and coloration (I use Genesis amplifiers, they are known to be one of the most neutral sounding amplifiers in the world, they are like the Yamaha of caraudio).
This way and only this way, you get the true sound of the speakers.

I'm not saying this is the only way to go, warmer sounding amps in combination with speakers that need some taming can sound just as great together, but it's easier to know for sure what chain of the install determines the overall sound and I like to have that chain as close to the end as possible.

Isabelle


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## Mooble (Oct 21, 2007)

MarkZ said:


> What's being amplified 100 times? The THD? We measure THD in percentage, so 0.1% THD is still 0.1% THD after being amplified. The noise? We measure noise as a ratio of signal to noise. So, if the noise is being amplified by 100, so is the signal, leaving you with the same THD. Same with frequency response -- a _relative_ measure.
> 
> So it doesn't really matter that an amplifier is there to amplify the bad things. It amplifies the good things by the same amount.


I should have clarified. I was thinking mainly of S/N. I had an Alpine 9853 that was somewhat noisy at low volumes (even though it spec'd fine, several people had the same complaint). You could tolerate it I guess, but when you really cranked the volume on low passages it sounded like you had two big sea shells strapped to your ears.


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## MarkZ (Dec 5, 2005)

Candisa said:


> Good sound starts with a good headunit, if the headunit isn't good to start with, you can never get a good sound out of the speakers...


Yes, if the head unit isn't good, you can never get good sound. But if the amp isn't good, you can never get good sound either. And if the speakers aren't good, you can never get good sound. Brilliant.


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## ErinH (Feb 14, 2007)

The end result is decided by the weakest compnent in your system. No matter what that component may be (install, tweeter, headunit, etc).


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## Candisa (Sep 15, 2007)

MarkZ said:


> Yes, if the head unit isn't good, you can never get good sound. But if the amp isn't good, you can never get good sound either. And if the speakers aren't good, you can never get good sound. Brilliant.


That's exactly what I'm explaining to the TS, yes, your point being?


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## MarkZ (Dec 5, 2005)

Yes, we agree. Something that doesn't sound good won't sound good. You make a very good point.


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## t3sn4f2 (Jan 3, 2007)

Can the weakest link analogy really be used here. Doesn't it come down to a _summation_ of powers in all links to give an audible or inaudible result. 

For instance, a chain of 1 "weak" and 3 "excellent" links could sound equal to 4 "good" links. 

No?


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## MarkZ (Dec 5, 2005)

t3sn4f2 said:


> Can the weakest link analogy really be used here. Doesn't it come down to a _summation_ of powers in all links to give an audible or inaudible result.
> 
> For instance, a chain of 1 "weak" and 3 "excellent" links could sound equal to 4 "good" links.
> 
> No?


Yep! It sums. It doesn't multiply. It isn't "weakest link". It's a sum, pure and simple.

Having said that...

As I pointed out earlier, distortion/FR/dynamic range differences are all completely dominated by the speakers. So, in effect, the sum is approximately equal to the weakest link: the speakers. There are exceptions to this of course. Clipping is one. F'd up noise issues like you described with that HU are another.


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## t3sn4f2 (Jan 3, 2007)

MarkZ said:


> Yep! It sums. It doesn't multiply. It isn't "weakest link". It's a sum, pure and simple.
> 
> Having said that...
> 
> *As I pointed out earlier, distortion/FR/dynamic range differences are all completely dominated by the speakers.* So, in effect, the sum is approximately equal to the weakest link: the speakers. There are exceptions to this of course. Clipping is one. F'd up noise issues like you described with that HU are another.


That would depend on the listening level though wouldn't it. Say I'm listening with the car off in the garage at normal volume, not loud what so ever. Would the speakers then be at the THD level of the other components? A 1 watt peak in that listening environment represents a decent average volume and at that level, 1 watt into the speaker is well below 1% THD like the device would be.

Frequency response differences at the ear aside though, that one would be dominated by the driver and would not get better at lower amplitudes.


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## ErinH (Feb 14, 2007)

Example. Weakest link: snr.


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## bassfromspace (Jun 28, 2016)

In the grand scheme of things, our ears are the weakest links.

Even ****ty electronics are far superior to our hearing capabilities, which IMO makes buying "high end" electronics (HU's, Processors, Amps) an exercise in futility. If a product has good design and is noise free (easy to obtain with today's manufacturing technology) then your foundation is solid.

Speakers and install, however, directly affect WHAT we're listening to and therefore merit the greatest amount of attention when planing.


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## MarkZ (Dec 5, 2005)

t3sn4f2 said:


> That would depend on the listening level though wouldn't it. Say I'm listening with the car off in the garage at normal volume, not loud what so ever. Would the speakers then be at the THD level of the other components? A 1 watt peak in that listening environment represents a decent average volume and at that level, 1 watt into the speaker is well below 1% THD like the device would be.
> 
> Frequency response differences at the ear aside though, that one would be dominated by the driver and would not get better at lower amplitudes.


I don't get what you're saying. Can you provide an example of the equipment that exhibits that kind of behavior?



bikinpunk said:


> Example. Weakest link: snr.


Noise adds.


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## t3sn4f2 (Jan 3, 2007)

MarkZ said:


> I don't get what you're saying. Can you provide an example of the equipment that exhibits that kind of behavior?


Maybe I'm wrong but doesn't a typical 7" driver have a THD level at 1 watt input that is below 1% the way a head unit would be? Or do the broad individual harmonics that are at -60dB and below in level add up to a THD% way higher then that of a functional head unit (relatively speaking)?

18W8531G


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## MarkZ (Dec 5, 2005)

Put together a similar plot for a HU and I think you'll see the harmonics off the bottom of the chart.


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## t3sn4f2 (Jan 3, 2007)

MarkZ said:


> Put together a similar plot for a HU and I think you'll see the harmonics off the bottom of the chart.


I'm a dumbass, I should have noticed that after all the RMAA device THD graphs I look at. :blush:


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## MarkZ (Dec 5, 2005)

I've had a hard time measuring source unit distortion. I'm just not equipped for it. Most of the source units I've measured have distortion buried in the noise. That's probably where the manufacturers come up with their THD+N values. My guess is that N>THD.


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## t3sn4f2 (Jan 3, 2007)

MarkZ said:


> I've had a hard time measuring source unit distortion. I'm just not equipped for it. Most of the source units I've measured have distortion buried in the noise. That's probably where the manufacturers come up with their THD+N values. My guess is that N>THD.


For sure....

Look at my soundcard


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## Zachyv92 (Apr 17, 2010)

Zachyv92 said:


> lets say i was to buy some cdt components for clear sound in my car..but at the same time i wanted to buy a low end flip out head unit for looks.. but then get a good quality amp for the speakers so they weren't running through the head unit.. would the crap head unit say clarion VZ409 (touchscreen) have an affect on the sq of the speakers even when the speakers are amped? thanks



So the main thing to look for in amps and hu's is low thd % , high signal to noise ratio, and I also learned that high damping factor is good for sq as well.. I think the nakamichi cd400 is a good choice however its pricy and the nak. Cd300 doesn't seem to have comparable specs. As for amps I've looked into the new soundstream 4 chanell references.. they seem to have good specs considering the price.. and most importantly I've settled on the ppi 356cs components as I've heard nothing but great things about them so far.. good choice of product? Lemme know what ya think


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## kyheng (Jan 31, 2007)

Our brain is the weakest link at all times. Because it will lean towards myths(if the marketing department do a great job on this) even we all know it is flaw.


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## ALL4SQ (Mar 28, 2009)

Why was this moved to the Dumb question forum?


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## t3sn4f2 (Jan 3, 2007)

ALL4SQ said:


> Why was this moved to the Dumb question forum?


Someone probably went off the thread title only, which is misleading.


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## pat_smith1969 (Feb 17, 2010)

MarkZ said:


> But your opinion doesn't make any sense.  It doesn't really matter where the crappy sound is coming from -- the HU, amp, or speakers. If it's present in the chain, at ANY point, then it's a problem.
> 
> The question people should be asking is this: how different is an expensive vs. cheap HU in comparison to the difference between expensive vs. cheap speakers. And the answer, almost always, is that the difference in speakers is much much bigger. By almost every measure, too. THD differences are much bigger for speakers, dynamic range differences are much bigger for speakers, and frequency response is much different between speakers.
> 
> ...


I have to say this is the most convincing post I have ever read here. I am a huge believer that your Source media then your HU are the most important parts of the system. But Mark Z makes a good point that at the quality of "GOOD" and above the electronics are going to sound pretty good, while the quality of a GOOD speaker will be noticibly less good than a speaker of GREAT quality.

One caveat to this is that with today's compressed media, a good D/A convert will help a lot, be it a Burr/Brown or a different 24 bit D/A. 

I would also like to point out that a speaker does nothing more than move in and out (oversimplification of course). The speaker moves acording to what the amp tells it, the amp just increase the signal from the HU... so it still comes down to the HU. But like MarkZ said, The difference between a $200 HU or amp and a $1000 HU or Amp will be small.. but the difference between a $200 set of speakers and a $1000 set of speakers will be pretty huge.

In the end if you are going to listen to anything other than Flac or other lossless media, you are just pissing in a rain storm.


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## MarkZ (Dec 5, 2005)

I recently converted almost my entire collection to the Lame V0 ("extreme") preset, which is a great balance between efficient encoding and high quality. I can't tell the difference between it and flac.

Anywya, when I made that post, I didn't mean for people to say "**** it, I'll spend $10 on the source unit and then spend thousands on speakers." I definitely don't want to discourage people from trying to achieve bitperfect digital output, or using quality DACs, or op amps or any of that stuff. I just believe, before we even begin to think about those things, we need to face the reality of how ****ty the car environment is, and how big a role the SPEAKERS and WHERE WE PUT THEM plays in mitigating that ****tyness.

I'd like to see people build their systems around the speakers. Say, "I want to put speakers here and here, and I want those speakers to play this frequency range at this volume." After they do that, THEN they can start choosing amps to power those speakers and HUs to process the signal. Too many people choose the opposite route. They say "I have this bright shiny audison amp and I want to power four speakers with it." That strategy will impose too many restrictions and biases towards your speaker selection and installation goals.


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## ErinH (Feb 14, 2007)

^ although it only "moves in and out" the sound you get is a factor of the speaker's makeup. Therefore, imo, the speaker is the most contributable factor to how a system sounds (barring dsp of course). Not all speakers sound the same. There's plenty of data to back this up.

Edit: upon re-read, I believe this is what you're saying.


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## sqshoestring (Jun 19, 2007)

Certainly electronics have improved in quality and price the last 20yrs, so HU and amps are better in the mid to cheaper end than they used to be. Still I say spend the most on the HU/processing and front drivers, that is the most of your SQ.

Back in the day you had to run a top of the line xover for example (analog) or you could not get a clean system. I had a Nakamichi and you could not pry it from my hands.

Amps do not make much difference now, its more a question of bogus power ratings and reliability/service. I'm sure I could run a fairly good system on Kenwoods or better. Subs are all about install and meeting your needs, most of them can work well in the right place even cheap ones...though in less places.

Drivers and install, IMHO the right one and right install make more difference, but it does depend on your needs. If you can only fit X size or need a lot of output, then you will have to spend more. Certain cars the doors suck for example, they need more install to work right. No doubt the more spent the chance of better SQ increases, though not in a linear way. Sure there is no doubt the drivers are going to vary the sound of the system more than anything and somewhat the install of them, and for subs the install is the largest factor if you don't expect the sub to exceed its capabilities.

I spend the least on subs and try to avoid expensive ones such as a small box sub setup that costs more, and requires a larger amp and more wire. But if you need or want one, then you use one instead of a larger ported or IB.


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