Crown XLS DriveCore 2 Series

[Zing]

Link to Crown Website

Tee calls me last night and tells me about a conversation he had with his friend (Ray). Their conversation went something like this:

R: You know how some people use pro audio amps in their HTs?
T: I know you're not supposed to.
R: Yeah, I used to think that too but these new Crown amps are the shit.

Tee tells me Ray starts absolutely gushing over these amps with the ubiquitous hyperbole "I'm hearing things I never heard before". Tee is skeptical but he trusts Ray and they have similar tastes so he decides to research this series of amps. Clearly, Ray is not the only one gushing over them. Now Tee is convinced enough to give one a shot.

Now Tee is telling me about his own personal, firsthand experience with the amp. He's practically wetting himself describing what he heard and felt. He too is hearing things he never knew existed before. There's more punch. There more dynamics. He said it's like he got new speakers. So convinced and elated, he buys two more. And calls me to tell me about them and suggests I look into them.

Some of the specs and features are kind of impressive for such a low price. Others are exactly what you'd expect at this price point (read: not at all impressive). The SNR seems low, the THD seems high, and there's no 12v trigger. I cite these things as reasons why I wouldn't be interested in such a thing. His response?
"Yeah I said the same thing as many others who come from home audio amps but I know what I’m experiencing is amazing and my ears tells me it sounds good!"

So let's debate the merits (or lack of) of these 4 amps, ranging in price from $300-$600.

 

[Flint]

I need to research that particular amp, but most pro amps have a high pass filter on the bass to protect them from running away due to inaudible subsonic feedback and unfiltered/limited inputs from live mics or instruments. One affordable Crown amp from a decade ago that gained a reputation for HT users turned out to be 3dB down at 20Hz with a very steep 48dB filter which had audible ringing issues. As a PA amp it was fine as sub-bass isn't typically reproduced, but in a home it made the sound fatter, looser, and sloppier - which apparently made users happy. A shitty sub can do the same thing.

So, I generally discourage pro Amps for true high fidelity subwoofer use.

For fullrange use, they tend to be similar in the ultrasonic treble range. Also, most tend to have a higher noise floor.

So, some pro amps can be amazing, but the ones which are tend to cost about the same per watt as a good home audio amp and often have cooling fans which are never off.

 

[Zing]

From what I've been able to gather so far, these amps have a high pass filter, a low pass, a band pass and a Linkwitz Reily 24dB slope. Also noteworthy is their input sensitivity adjustment for RCA inputs.

Cut sheet

 

[Flint]

From what I've been able to gather so far, these amps have a high pass filter, a low pass, a band pass and a Linkwitz Reily 24dB slope. Also noteworthy is their input sensitivity adjustment for RCA inputs.

Cut sheet

Those are the DSP capabilities. I was referring to a non-defeatable "passband" filter which allows the 20-20,000hz range "pass", but steeply filters off everything outside that range. Since PA systems generally operate in 40Hz to 15,000 Hz range, the fidelity issues of those aggressive filters tend to be a very minor issue.

These amps also have fans, so... there's that.

The S/N rating is 97dB, which is lower than nearly all decent home amps, but I need to see the 1W S/N measurement to make anything of the cut sheet spec.

The signal goes through a A/D process all the time, so if you think multiple digital conversions is a bad thing, this is a detriment.

All pro amp have gain controls, having a separate gain for the RCA input means nothing to me - unless I am also using the 1/4" and/or XLR inputs.

Really, while this amp might work well and make sound, I cannot believe it can compare to a similar output from a hifi amp. A good solid state amp should never add to the sound... a straight wire with gain, as Hafler used to say. If this amp "sounds" significantly different to a good home amp, what is it adding or subtracting from the sound? Can you consider it accurate?

 

[Batman]

Could this be a case of they’re amazing or mind blowing “for what they cost” based on the spec sheet? That MB Quart speaker thread comes to mind. Everyone thought the same thing, yet almost everyone wound up replacing them anyway.

 

[Flint]

Could this be a case of they’re amazing or mind blowing “for what they cost” based on the spec sheet? That MB Quart speaker thread comes to mind. Everyone thought the same thing, yet almost everyone wound up replacing them anyway.

Maybe, but the question is what are they comparing this amp to? Compared to a midrange receiver, yeah, the Crown probably will sound better. Compared to a top end receiver, I would question any improvements other than the added power (assuming the listening levels are very high, the room is huge, or the speakers are very inefficient). Compared to a good stand alone hifi amp, only peak power increases might matter, but the detriments like the fans, the, ringing filters, ADC processing, noise floor, should be a problem.

I can definitely see situations where switching to ok ne of these amps would make a positive difference, but there are typically more reasons to buy a good hifi amp in those situations.

 

[MakeMineVinyl]

If this guy is "hearing something", it is probably a distortion. He might like it, but it is probably a distortion.

For the record, the tube amps I like so much are in fact distorting the sound. I like the sound of the distortion, but it is distortion none the less.

Just humble musings from the sausage factory.

 

[Deerhunter]

They have really good reviews over at the other stereo fourm. They have also said the fans have not very quite when they have came on. But you have to really drive them for that. Been kinda thinking about one.

 

[Flint]

I've been watching the used sites to see if I can get one cheap. I'd love to put it on the bench and measure its performance.

I am not convinced by random user reviews as I can probably find more reviews that a given power cable upgrade makes a "night and day" difference that the owner's "wife" noticed without provocation than I can find positive reviews of this Crown digital amp. I need some evidence I can trust, like a proper test review - but I cannot find any. Not a single reviewer had written a proper electrical review of these amps with true high fidelity as the standard.

 

[Deerhunter]

Well my wife did ask why my stereo sounds really good again. I found my soundhound pee, and added it to my new speaker wires.


It would be interesting to have that type of test on that amp. Is it really really good? Or is it all smoke and mirrors?

 

[MakeMineVinyl]

Every day of the week I'm drowning in a sea of power amps from cheap to ultra expensive high end. If used within their power capabilities etc, they sound pretty much identical. Why should this Crown amp should be any different?

 

[Flint]

This morning I visited a burgeoning new Audiophile in my neighborhood, a 55 year old with a mid-life crisis about to explode, who fell in line with the "the DriveCore 2 amps from Crown are the best amps in the world". He owned three of them in his Home Theater being driven by a Denon A/V receiver's line level outputs. He also happened to have a couple of Parasound New Classic amps in the house which used to be his main amps before "upgrading" to the Crown amps. So, simply put, I listened to them and they functioned just fine and the speakers sounded like his speakers (B&W mid-sized bookshelf speakers, I forgot the models or lines).

When I connected the prior Parasound 275 90 watt amp to the left speaker and left the Crown XLS1002 215W amp on the right speaker and adjusted the gain levels to the exact same gain (used a 120Hz mono signal and used a multimeter to measure at the speaker terminals and adjusted the Crown amp until the two signals were exactly the same voltage), I could tell the Crown amp had more self-noise. While the hiss wasn't obvious at normal listening levels from the listening position, we could both hear the hiss from the Crown amp standing about a foot from the speaker while the Parasound amp required we darn near had to press our ears against the tweeter to hear the hiss. This is not complete proof the Crown amp is useless, but it does show the design differences between a pro-sound amp and a home audio amp.

Connected in stereo for listening tests at pleasant listening levels (in his room the acoustics made everything wash out at the levels which I prefer to listen), the Parasound amp seemed to sound cleaner and more natural - in other words, I thought I was listening to the speakers, room and music and the amp was generally invisible. Calibrated for matching the gain levels (something the owner never tried) and calibrating for the same listening levels, the Crown amp seemed to add some very subtle thickness to the sound. However, I am a skeptic and it is entirely my preconceptions clouded my perceptions of what I was hearing. That said, in the silent passages in the music, like the gap between songs, I could hear the fan operating to cool the amp, which is pretty damning for a super nerd like me. When the AC was on, I could not hear the fan, when the trash collection truck was outside the owner's house I could not hear the fan. When the refrigerator in the adjacent kitchen was operating I could not hear the fan. When there were no other non-constant noise sources I could clearly hear the fan after listening for about 15 minutes at reasonable levels (about 10dB SPL softer than my typical critical listening levels). If I were in a well designed and implemented HT room which should have an effectively silent ambient noise level, I believe the fan would be (figuratively) deafening.

I will say this, the owner was FAR less impressed with the Crown amps after listening at matched levels to the Parasound amp. Because the Crown amps have much greater gain than the Parasound amps he replaced, the SPL in the room was considerably louder than when the receiver was set to a given volume level. In other words, the Crown amps were significantly louder when the receiver was set to his reference level. He had no idea he could, and probably should, adjust the amp's gain controls to at least reduce the noise levels and even more sophisticatedly maximize the volume range of the receivers level control. After perfectly calibrating the levels, the Crown amps sounded more similar to him than he ever expected.

I encouraged him to enjoy his investments, though. Going from a 90 Watt amp to a 215 Watt amp will net him an additional 4dB, or so, of output and reduce the likelihood of clipping from maxing out his amps. His speakers are not terribly efficient, so a bigger amp has some very real benefits for him. I also didn't go on to ask to borrow one of the amps to put on the test bench because he was looking a little like a deer caught in headlights from my inadvertently bursting his bubble. I didn't tell him everything I wrote here, but he could see and hear what I was focused on and made his own realizations.

The room was awful, though. He wife helped him decorate, and it was an acoustical nightmare with the most common and worst aspects of decorating killing any opportunity to make a room pleasing for sound reproduction. It was a terrible. But, he seems relatively happy with things, so I just left well enough alone. He was very disappointed I didn't do my critical listening at significantly higher SPLs, but I wanted to hear the speakers and the detail in them more than the room's washed out bouncy, reflective nightmare.

That's my little review.

To summarize - I believe the Crown amp works perfectly fine and is probably a very good option for an audio enthusiast's first foray into separates do to the value per watt and generally decent performance. It does have drawbacks in the noise floor appears to be higher than even a modest home theater amp and the fan is subtly audible when the amp is in the room. I think I heard a difference in the sound between the Crown and the low end Parasound amps (favoring the performance of the Parasound), so I am reserving judgement on the absolute fidelity of the Crown.

I do know this... I would never ever replace an amp with comparable power output with Crown XLS amp. The higher noise floor and potential for audible fan noise both are enough to disqualify these amps when the benefits are not specifically high power and current capacity.

 

[Flint]

So, to the effects of upgrading to this amp...

Claims I've seen here and on other forums and user reviews:

More Punch - Any time you turn up the volume and generate more SPL, the sound will perceptibly have more bass and treble. It will seem to be punchier and appear to have greater dynamics. You can increase things by as little as 1.5dB SPL and the perception will be that it has more "impact," bass output, and "punch." That is the nature of our perception of sound and understanding the Equal Loudness Curve will make this illusion obvious to the learned audio nut. If a user gets more gain from the Crown amps (in that for a given voltage at the input you get more watts at the output than with a standard home audio amp), it will simply be louder for a given volume setting on the receiver / preamp. Louder always means punchier, more dynamic, more bass and treble, and so on. That's just how it works in our heads.

More Dynamic - See "More Punch"

Got New Speakers - This is surely somewhat hyperbole, but it is also important to note that if one listens at very high SPLs and the room is somewhat large, the speakers are somewhat far from the listener, and/or the speakers are not terribly efficient, that a 125 watts may not be enough to satisfy the demands being put on the system. While very slight peak clipping may not be blatantly obvious, it is audible when compared to the same SPLs without minor peak clipping. So, going from a 125W amp to a 215W amp in situations where the listener is pushing the levels right to the edge of overtly obvious clipping of the smaller amp, the difference will be very significant. It could seem that one has new speakers because the sound is cleaner and less subtly distorted at those high SPLs. So, for this sort of listener, an amp like the these Crowns is likely to be a great upgrade.

Best Amp in the World - Great, whatever. I am the best lover in the world, but you don't see me bragging about it.

Quieter than my old _____ Amp - I have doubts this sort of statement is ever true assuming the old amp was working properly.

 

[MakeMineVinyl]

One thing not mentioned here is that this amp appears from the Crown website to be a class D amplifier. This is going to change a lot of things when connected to actual speakers, as class D amps differ in how they work and sound compared to more traditional class A/B amps. Generally, I don't like class D; its lots of "cheap" power, although this class of amplification is used in a lot of very upscale amps, including ones I work with every day. But then I prefer tubes, so you know where I'm coming from......

The gain is about 30dB, which is just a bit higher than standard home amps, although the Crown apparently has a switchable gain setting where this can be raised by +6dB to 36dB. This gain setting will show an obviously higher loudness per input level than a standard home theater amplifier (the gain is generally 29dB for home amps, and this was standardized by THX).

Why a class D amplifier would need a fan is a total mystery to me, as they generate very little heat. They're least efficient at idle.

Flint, I'm curious; what test gear do you use for your amp testing?

 

[Flint]

Flint, I'm curious; what test gear do you use for your amp testing?

I have access to Dell's design and testing facility in Round Rock through old friendships. They have a latest Audio Precision gear and loads of other stuff which can make absolute empirical reference grade measurements.

But, for the sake of a public forum and to encourage the hobbyists, I also run some comparative tests using gear any audio nut could easily own, like basic RTA apps, off the shelf audio A/D interfaces, and jigs with speaker loads and such. The results are not empirically perfect, but they can be used to compare two amps side by side using the same testing rig. For instance, I have a jig consisting of a 150W non-inductive 8 ohm resistor with an added heat sink which can present a consistent load to the amps under test which a nice resistor network to drop the voltage for a tap which can feed the input of an audio interface on my 24bit 96kHz audio interface. With that I can measure from 10Hz to 40kHz things like frequency and phase response, IMD, THD to 13kHz, etc. By performing the exact same tests on the same rig on the same day with two or three amps can show the differences between them. Any serious enthusiast could repeat the comparison test, even though it would not be empirical.

 

[MakeMineVinyl]

Oh, I don't think there's any reason to "encourage" hobbyists; while performing audio measurements on a power amp isn't rocket science, it isn't trivial either, and requires at least competent technician level skills. Also, there's real potential to blow up an amp if for instance a measurement on a floating (balanced output) amplifier - and many, many are - is attempted and one side of the measurement gear gets grounded somewhere along the line. Fully balanced resistive pads and fully floating test gear is needed in this instance. So please don't "encourage" too much, as there is real danger of fucking something up!

 

[Flint]

I wish someone would provide proper bench tests of these amps.

 

[MakeMineVinyl]

You will probably have to do it yourself at Dell if some pro sound magazine doesn't step up. A wrinkle will be that since its class D, an AES-17 filter will be needed. By the way, even class D amps can be fully floating and balanced, aka differential; some we make are.

 

[malsackj]

I have 4 of the xls amps. 2 1500 and 2 2500. one of the 1500's is in a rack bag. I use this from time to time for audio jobs. If mailed out how quick would it be returned. about 1 month. The Rack weight in the picture is 100 lbs. My back up Carvin Fet 1000 is 56 lbs compared with the XLS 1500 at 12 lbs. So the Amp rack lost 90 lbs of weight on three amps out of four. The Behringer 4 channel would have to be two amps at another 80 lbs.

 

[malsackj]

yes they are the original model previous.
https://www.crownaudio.com/technology

DriveCore™ Technology provides an extremely wide-tolerance with regards to sagging or "dirty" AC line conditions providing consistent performance without affecting audio quality. This means that your performance will not be compromised by fluctuating generator power or overloading by lighting rigs, backline gear, etc.

The switching power supply does not handle dirty AC from Generators very well. Killed the first one the first time I tried just powering on. Have not tried Generator again. Crown repaired under warranty. Just shipping and handling.