# Class D amp on horns...



## damonryoung (Mar 23, 2012)

I am considering a couple JL XD amps because I have a size constraint I would like to stay within... But, I am a little concerned with "noise" showing up from the amp in the horns...

I wanted to see if there is anyone out there using Class D amps on their horns...

Thanx
Damon


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## minbari (Mar 3, 2011)

what kind of "noise" are you concerned with?


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## damonryoung (Mar 23, 2012)

I guess I'm concerned with any noise that is not a part of the "soundtrack"... 

I'm pretty sure that whatever "noise" the amp would make would be magnified by a driver that is as efficient as a horn...


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## minbari (Mar 3, 2011)

but that is true for any amplifier. Class has nothing to do with it. Class D has the potential for inductor distortion on the output, class A/B has potential for zero-cross distortion on the output. pick your poison 

buy a good quality class D and it will perform just fine.


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## t3sn4f2 (Jan 3, 2007)

minbari said:


> but that is true for any amplifier. Class has nothing to do with it. Class D has the potential for inductor distortion on the output, class A/B has potential for zero-cross distortion on the output. pick your poison
> 
> buy a good quality class D and it will perform just fine.


x2, and if IIRC the XD line has excellent noise performance.


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## Neil_J (Mar 2, 2011)

The XDs are 75 watts per channel. If your you're using high efficiency horns, you'll end up turning the amp gain DOWN, relative to your midbass and sub -- which would reduce noise, not increase it. If you don't turn the gains down, your ears will bleed, or your curve will be very top-heavy 

As others have mentioned, the XDs are a great series of amps.


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## WLDock (Sep 27, 2005)

DRTHJTA said:


> But, I am a little concerned with "noise" showing up from the amp in the horns...


*JL AUDIO XD200/2*
-S/N Ratio, referred to highest rated power >104 dB below rated power (A-weighted, 20 Hz - 20 kHz noise bandwidth) 
-S/N Ratio, referred to 1 W >84 dB (A-weighted, 20 Hz - 20 kHz noise bandwidth) 


*JL AUDIO Slash 300/4v2*
-S/N Ratio, referred to highest rated power >108.5 dB (A-weighted, 20 Hz - 20 kHz noise bandwidth) 
-S/N Ratio, referred to 1 W >89.5 dB (A-weighted, 20 Hz - 20 kHz noise bandwidth) 


So what "noise" are you referring to? The Signal to Noise of the XD amps is not much different than the Slash amps...both which are very good. The modern class D amps from JL are pretty good....let you ears decide!


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## DT053 (Mar 23, 2007)

I used the small Xtant 1.1 class D amps on my horns without an issue. But, I do understand where you're going with this. I did use other amp that I could hear noise from. Not sure if it was johnson noise or what, but the horns sure brought it out.

Donnie


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## jpeezy (Feb 5, 2012)

manville and lucio are very picky about the sound of their products,if they put it out it, it will sound good,will you have switching noise,not on any decent current product,back in the day infinity made some tiny digital amps,class d,they sound very good,but they were the only ones. now there are quite a few,they started out in use in subwoofer amps,because most humans cant tell the difference between 1% and 10% in low frequencies.but technology has allowed designers and manufacturers to produce some very good sounding full range class d amps.now the only thing i see getting neglected a little bit(and it would probably only matter to people such as on this forum,the audiophiles and sq nuts,me included)is the signal to noise ratio and stereo seperation tends to be a lil low,some of the old school sq guys ,speakerworks, image dynamics,they usually built their horns systems utilizing bridged amps on individual drivers (to drive up stereo seperation),and they used the apogee(and other brands) d/a converters because they had super high signal to noise ratio(why high s/n? better dynamics lower noise floor,better control,)the best way i can liken my own experiences to the outboard d/a, imagine going out in the morning and looking across a slightly foggy cornfield,you can see most of the corn stalks but not well, but imagine the difference when you can go out and see every little detail and nuance in that field of corn stalks)imagine the difference if the corn was music. the amps will sound fine.but the differences i ve seen in amps as above the "mini amps" versus non mini,ive used both extensively and can you here a difference,maybe if your real picky,but there is a difference in specs,look at arc's ks non mini and a comparable mini amp,the s/n is lower on the mini (less headroom?)and sometimes stereo separation is sacrificed,(i am a big fan of the arc amps mini or not).


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## jpeezy (Feb 5, 2012)

1% and 10% distortion. Sorry it was so wordy.


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## Pimpnyou204 (Jul 13, 2011)

agreed i use the arc ks 300.4 and love it for the price range its in and its very small size.


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## subwoofery (Nov 9, 2008)

Pimpnyou204 said:


> agreed i use the arc ks 300.4 and love it for the price range its in and its very small size.


Using KS300.4 with horns? 

Kelvin


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## Pimpnyou204 (Jul 13, 2011)

subwoofery said:


> Using KS300.4 with horns?
> 
> Kelvin


No so far sub midbass midrange and tweets haven't tried any horns on it yet


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## subwoofery (Nov 9, 2008)

Pimpnyou204 said:


> No so far sub midbass midrange and tweets haven't tried any horns on it yet


I asked coz the thread and sub-forum is about horn and the OP specifically asked about class D on horns. 

On "normal" drivers, the DLS Ultimate amps are dead quiet and great amps. 
Paired with a CD1e v.3 (107dB 1w/1m), the noise floor is heard. 

I have no doubt that the KS amps are great but unless someone has tried a KSxxx.x on horns, I would recommend the OP look elsewhere. Horns impedance can do strange things to amps that puts out the same power @ all impedance (JL HD). 

Minbari did bring out a good point on the zero-cross distortion. Believe there's a thread about it... 

Kelvin


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## basshead (Sep 12, 2008)

subwoofery said:


> I have no doubt that the KS amps are great but unless someone has tried a KSxxx.x on horns, I would recommend the OP look elsewhere. Horns impedance can do strange things to amps that puts out the same power @ all impedance (JL HD).


The KS are unregulated class A/B amp, the only twist is that they are call G/H class because they have a variable voltage rail. So because of their powersupply they are more efficient than pure A/B but less than D.


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## subwoofery (Nov 9, 2008)

basshead said:


> The KS are unregulated class A/B amp, the only twist is that they are call G/H class because they have a variable voltage rail. So because of their powersupply they are more efficient than pure A/B but less than D.


I know all about the G/H class  and the fact that KS line is using that topology 
I just wanted to point out that since it hasn't been used on horns, the recommendation is not really valid. 

Kelvin


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## subwoofery (Nov 9, 2008)

And I know the KS is unregulated too  

Kelvin


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## minbari (Mar 3, 2011)

subwoofery said:


> Minbari did bring out a good point on the zero-cross distortion. Believe there's a thread about it...
> 
> Kelvin


it is an issue. since horns are so efficient you will be using less than 5 watts most of the time. At 2 watts you have 4vac of signal. With your basic BJT you will have 0.7v x 2 (one for push, one for pull) for the diode drops. same thing happens with mosfet output (for different reasons) There are ways to mitigate this, but no way to get rid of it entirely.


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## minbari (Mar 3, 2011)

subwoofery said:


> And I know the KS is unregulated too
> 
> Kelvin


never been a fan of unregulated amplifiers. they have the advantage of gaining more power the higher the input voltage is, but a strongly regulated amplifier will put out the same wattage no matter what the input is (within reason)


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## thehatedguy (May 4, 2007)

What little I have played around with horns so far in my car, the JL HD amps are sounding great on them.

Though I wish I had a little more flavor and could afford another another HSS tube amp.


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## subwoofery (Nov 9, 2008)

thehatedguy said:


> What little I have played around with horns so far in my car, the JL HD amps are sounding great on them.
> 
> Though I wish I had a little more flavor and could afford another another HSS tube amp.


Just wondering what your horn's impedance curve looks like... Did you test it? 

Kelvin


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## thehatedguy (May 4, 2007)

Nope.

Might have a change of plans though. Big coaxes have really caught my fancy lately.


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## subwoofery (Nov 9, 2008)

thehatedguy said:


> Nope.
> 
> Might have a change of plans though. Big coaxes have really caught my fancy lately.


That's car audio for your right there ^  

Kelvin


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## thehatedguy (May 4, 2007)

Been wanting to put the HSS in the car...and that is the easiest way to do it- 8 or 10" coaxes up front with a pair of 10s on the rear deck playing up to 100-150.


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## jpeezy (Feb 5, 2012)

what kind of coaxs?prosound or european?hey i will be using a arc ks300.4,on some horns and 10" midbass so ill let you guys know what it sounds like.and i wasnt trying to say the arc mini amps are class d, but as you go down in size,especially that much, your going to sacrifice something.I dont recall if the jl hd amps have transformers in the output circuit like the slash do,but it usually helps speakers sound better spectrally by smoothing out the impedance bumps and dips,which usually causes peaks and roll off,horns typically roll off in the bottom end because of there impedance curves.similar to mcintosh tube amps that have transformers on there outputs,which a lot of home audiophiles use on their horn setups.


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## thehatedguy (May 4, 2007)

Pro for sure.

Hard to find good pro 8s...but settled on BMS or B&C.

I think.


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## t3sn4f2 (Jan 3, 2007)

thehatedguy said:


> Pro for sure.
> 
> Hard to find good pro 8s...but settled on BMS or B&C.
> 
> I think.


Center firing up at the windshield? Enclosed? Tell me tell me!


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## thehatedguy (May 4, 2007)

Yes and yes.

That's all I have to spill right now. And I am stuck until someone picks up some of my stuff forsale.


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## t3sn4f2 (Jan 3, 2007)

thehatedguy said:


> Yes and yes.
> 
> That's all I have to spill right now. And I am stuck until someone picks up some of my stuff forsale.


Cool, hope it works out well.


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## fish (Jun 30, 2007)

thehatedguy said:


> Pro for sure.
> 
> Hard to find good pro 8s...but settled on BMS or B&C.
> 
> I think.



I think Mikey posted that he thought the B&C mids had a laid back sound to them. Would you agree?


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## bitperfect (Oct 1, 2010)

jpeezy said:


> what kind of coaxs?prosound or european?hey i will be using a arc ks300.4,on some horns and 10" midbass so ill let you guys know what it sounds like...


Any update, have you used the Arc KS series with horns?


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## jpeezy (Feb 5, 2012)

no sorry,project moving slowly,you know what they say,"the shoemaker always has the worst shoes!"part time stay at home dad,part time student ,and part time fabricator,finding good hands on free time is a lil hard.i am getting ready to order the new compression drivers(d2500ti or 220ti?)i may have to go with the smaller 2500ti to fit in my 2008 xb,also need to get my old d210ti's sold.looking at the b&c 10 neo for midbass.but as soon as i get to try the arc 300.4 on the horns ill let you know.


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## thehatedguy (May 4, 2007)

2500Ti over the 220Ti


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## bitperfect (Oct 1, 2010)

Thanks Jpeezy, 
My last final is tomorrow woohoo! :biggrinflip: 
I will finally have some time to work on my car. I might find out how they sound on horns sooner than you  I figure if I don't like it I can use the amp on my midbass.


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## jpeezy (Feb 5, 2012)

Good luck on finals,just started java(mind bender).if you find out how the300.4sounds let me know, I think it will surprise you.good luck,I'm jealous


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## Patrick Bateman (Sep 11, 2006)

DRTHJTA said:


> I am considering a couple JL XD amps because I have a size constraint I would like to stay within... But, I am a little concerned with "noise" showing up from the amp in the horns...
> 
> I wanted to see if there is anyone out there using Class D amps on their horns...
> 
> ...


I have a Honda Accord, and I use Class T on my projects because it seems to reject alternator whine better than the class AB amps I have. Compression drivers have very high efficiency, so noise is a real p.i.t.a. with them. YES they play louder, but the efficiency raises the noise floor. I am no expert on amplifiers, but as I understand it, digital amps are inherently noisy, so they tend to include a lot of circuitry to suppress noise.

If you don't mind throwing away some efficiency, an l-pad on the compression driver can lower the noise floor.

Note that it lowers the efficiency but shouldn't affect the dynamics much, because most speakers are limited by displacement, as long as you have enough power on tap.


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