Crown XLS2502 Stereo Amplifier Review

[Xulonn]

I cannot believe how a fair number of people here at ASR insist on judging this amplifier by the standards for a sophisticated audiophile amplifier instead of the PA/utility amplifier that it actually is.

In it's class and price range, it is a truly excellent performer and an outstanding value. And it is only an excellent foundation for an "audiophile" sound system if your goal is to accurately reproduce a live rock concert at your local stadium - or a boozy night of live music at a local bar / saloon / night club.)

Below is a photo of the first recorded music I ever purchased - a mono LP in about 1958. I still have a copy of that LP sitting a few feet away from me in my "office/media room". It's a studio production, and not not a "live" recording. I still occasionally listen to a ripped MP3 copy of that album that I downloaded.

I have no desire to reproduce anything but excellent, low-distortion HiFi sound at home - not the sound signature that reminds me of the many live nightclub gigs I have attended over the decades. Although I respect amps like the Crown for what they are and what they do, I would not trade my vintage Classé 70wpc Model Seventy stereo amp for any Crown amp.

 

[JohnBooty]

Another reason for amps with ridiculous levels of power would be inefficient speakers like Magnepans. I only had one experience with Magnepans and they were absolutely lovely, but they seemed to be soaking up all the power that a pair of fairly powerful monoblocks could provide. I am told that Magnepans don't need gobs of power, but they do if you want some decent bass out of them.

Do you know why is that? I have the same experience but I don't know why.
Most people said 5W or 10W is enough to drive the speaker to a very high SPL.

I'm not entirely sure... I would love to figure it out in objective terms. Perhaps it's as simple as reproducing music's dynamic peaks with absolutely no compression or audible distortion. Or perhaps it's slew rate? I also can't totally rule out observer bias.

I do know one thing though. It takes high efficiency, high output speakers and/or fairly beefy amp to convincingly simulate the dynamic range of a live orchestra performance, or even just a single instrument. If you have ever been in the same room as real, live instruments being played you know that their dynamic range is insane. A little old bookshelf speaker can sound great, but can't ever really simulate that sort of impact. That takes efficiency, lots of power, or both.

On the other hand...

Yes, it's true that low power systems can sound amazing. At Capital Audiofest, many people agreed that the best sound of the show belonged to a pair of Monitor Audio M3 Sapphires driven by a mere 10 or 15W amp. I know they were my favorites. And those are not even terribly efficient speakers.

So I would never say that "high efficiency, high output speakers and/or a fairly beefy amp" are the only way to go. But, I would urge audio hobbyists to hear a system that fits those parameters if possible. It think it really puts things into perspective.

 

[Matias]

No doubt, but why should we accept the worst kind of distortion at a level where they can be audible from a serious manufacturer?

Because it's cheap.

 

[confucius_zero]

Don't care how good the SINAD is at 5 watt.

but how loud is 5 watts for say a 90db sensitivity 8ohm speaker?

 

[daftcombo]

but how loud is 5 watts for say a 90db sensitivity 8ohm speaker?

Like 97dB.

 

[JohnBooty]

but how loud is 5 watts for say a 90db sensitivity 8ohm speaker?

About 95dB at a distance of 8 feet, assuming we're talking about a pair of stereo speakers, depending on room and speaker placement.

We might think that is as much (or more) power than we would ever need. But, this is a little misleading.

Obviously none of us should be spending much time listening to music over 75dB average, for safety's sake.

But if we drive a pair of typical bookshelf speakers with e.g. a cheap 5W chip amp it is not likely to sound great. The dynamic peaks in our music are likely going to wind up distorted in unpleasant ways. It won't sound very alive. With more power and/or more efficient speakers we can reproduce those peaks in an uncompressed and distortion-free way. This is where having hundreds of watts of instantaneous distortion-free power can help things sound good even if we are being (semi-) responsible adults and keeping our average SPL levels at safe levels.

 

[Francis Vaughan]

but how loud is 5 watts for say a 90db sensitivity 8ohm speaker?

log(5) * 90 = 97db @ 1 metre in free field. Similar to the noise level of using a kitchen food processor. 2 metres away in the free field and you are back to close to 90db.
A full orchestra can make you flinch. A good seat is going to see sound levels peaking over 110 db. Rock concerts will see 120db. That needs 1000 watts into your nominal speaker. And rock concerts generally have poor dynamic range, so that is a much more sustained power. But even orchestral music can reasonably demand hundreds of watts into passably efficient domestic speakers to achieve lifelike dynamics. Reference level for THX home theatres is 105db. Many domestic speakers are at the absolute end of their peak output trying to get even this loud. The levels of distortion products rises dramatically when they do. You can easily see distortion products only 20db down as they get driven hard.

 

[JohnBooty]

In it's class and price range, it is a truly excellent performer and an outstanding value. And it is only an excellent foundation for an "audiophile" sound system if your goal is to accurately reproduce a live rock concert at your local stadium - or a boozy night of live music at a local bar / saloon / night club.)

They're not perfect, but they're much better than you're describing!

Are they as nice as your Classé or a Benchmark AHB? Oh heck no. Please, nobody twist my words around to make it look like I'm claiming this.

But, I've heard high-end amplification and I've heard countless PA systems.

Objectively and subjectively, for home use these XLS amps are much closer to the former than the latter.

As has been much discussed on ASR, the kind of distortion Amir has measured here is not hugely impactful. It's kind of bordering on what's audible and what isn't.

Plugging a nice pair of speakers into these XLS amps is not going to turn them into some kind of nasty distorted PA system... just like plugging your Classé into a bar's sound system would not turn it into an audiophile dreamland. That is because the vast majority of distortion in a live music venue is coming from other sources: speakers, the room itself, etc.

 

[gattaca]

I had higher hopes for this one. I have passive sealed subs so it would be nice with something that's flat to 5Hz at least. Looks like this one starts dropping at around 80Hz. LAB Gruppen PDX3000 looks interesting. But also measurements of the Behringer EP4000 would be interesting.

From Amir's testing, the Crown XLS2502 seems like it will perform admirably driving a hungry load with a few compromises. You are correct that for big subs, which do well with this type of power, the XLS2502 is not "ruler flat to 5Hz." (Sadly, I was hoping it would do better there too.) FWIW, I have found a precious few AMPS that can reach into the 10-5Hz in a 8/4/2 ohm stable load - period... and at this price point, that number drops to virtually 0. If we want to step above this price point, then there are a few which surface - both current and vintage. Crowns are also suppose to be reliable and built better-than-most but that's just my general impression from hours of reading forums - we each have our favorite "brands!" If you are patient, a used XLS2502 can be had for $350 USD while an open-box is closer to to the $450/500 USD range.

So you ask what a XLS2502 might drive?

• In addition to the massive wall of subs posted above (WOW, that is SOME setup!!), difficult speaker loads such as Magenpans which hover in the 86-88 dB range at 4 Ohms.
  • Maggie fans don't buy Maggies for efficiency but that's another thread.
• A small array of ButtKickers which impart visceral dynamics to the entire room when installed like below.
  • The BKs are 4 ohm loads each (I measured them) and require 400-1000 Watts per unit to properly drive these heavy motors.
  • Their frequency response is 5-200Hz so the Crown XLS2502 can deliver a reasonable compromise on cost, performance, reliability, availability, ...
  • These BKs are:
    • thermally protected (I've disassembled and see then snap disk) and
    • are harder to destroy b/c the current carrying windings / wire does not move - the floating centered magnetic piston does.

-> https://thebuttkicker.com/buttkicker-lfe/

 

[RayDunzl]

Repurposing the power amps for use at home after the band goes bust is, I think, a time honored tradition.

They sure beat anything else we had at hand.

Besides, your speakers will distort more than the amps will.

 

[Francis Vaughan]

On the subject of driving subwoofers and frequency response, don't overlook the physics of the driven speaker and its maximum capabilities. Subs are typically excursion limited before they reach any other power limitation, and a sealed sub will quickly exceed is excursion limits when driven at frequencies below its resonance, even at quite low power inputs. (A ported sub gets a bit more wiggle room, but not much. Once the port unloads, the driver's excursion rises rapidly again.) Even if a speaker shows a flat frequency response down to quite low frequencies, you will usually find that (sadly) its power handling at those frequencies is vastly less than at slightly higher frequencies. The bottom octave is very hard work. Worrying that an amplifier is flat to 5Hz is a waste of time. If you are intending to get any sort of serious power out of the sub you would be looking to ensure it isn't driven with signal of frequencies much lower than its resonance, and one might want to calculate the maximum power levels versus frequency. Doing so can be disappointing. But it might avoid the even greater disappointment of slamming the voice coil into the pole piece and instantly killing the driver.

 

[Willem]

Hence the dsp in modern subs, to keep them inside their capability envelope by reducing extension when power goes up.

 

[NTomokawa]

At least the advantage of buying a big-brand product is having safety certs. A CSA mark!

 

[confucius_zero]

About 95dB at a distance of 8 feet

Then getting a high SINAD at listening distance is preferable than just power power power.

 

[anmpr1]

One benefit of this class of pro gear is that you can typically get it locally at your favorite guitar store, or order on line at a place like Sweetwater. Then try it out for 30 days and if it is not what you need, return it for a full refund. They don't care, and are happy to process returns. At least that has been my experience.

You could also buy direct from Harman, but my recent experience with them convinced me to buy locally, or at Sweetwater. YMMV.

 

[JohnBooty]

Regarding audibility of these measurements.

My primary listening environment these is my office desktop. Topping DX3 Pro (105dB SINAD... thanks ASR) through Parts Express' wonderful C-Notes DIY speakers, as well as various headphones: Beyerdynamic DT990, Grado sr125, HifiMan 400i. Not a high-end setup by any means but I think we would agree the headphone+amp combos are not too terribly lacking. So that is my reference point.

Is there a difference between that listening environment and the ~70dB SINAD Crown XLS amp in my garage man-cave, powering BIC America speakers?

Yes, but not nearly so vast as the numbers suggest.

I have some classical tracks on my test playlist that I know well: high dynamic range recordings of Ravel's Bolero and Stravinsky's Firebird Suite. I have listened to them many many times on my DX3 Pro + headphones as well as the XLS-powered monstrosity in my garage.

Obviously the XLS setup gives up some detail compared to the DX3 Pro + headphones. But everything is there on the XLS: I hear individual instruments with ease, etc. Subjectively it is very enjoyable.

I like ASR because it's awesome to see and hear the progress of well-engineered, high-end audio. And I am a firm believer that better-measuring gear is better-sounding gear. But, it's not a direct 1:1 relationship between measurements and listening enjoyment.

Then getting a high SINAD at listening distance is preferable than just power power power.

Sure, but lots of clean power is part of achieving that nice high SINAD.

Suppose we are listening to our program material at an average of 75dB. Well recorded material might have 30dB dynamic peaks. So we would like to be able to do 105dB (75dB + 30dB) cleanly so those peaks sound great. Ideally perhaps even more like 115dB.

Assuming two 90dB efficient speakers at 8ft, with some boundary gain...

• 5W per channel would give us 95dB
• 100W per channel would give us 108dB.
• 250W per channel would give us 112dB
• 600W per channel would give us 116dB

I wouldn't call a setup with high power amp and/or high-output speakers "necessary." But, there are benefits. Definitely worth hearing with your own ears to make up your own mind as far as how these various measurements correlate with listening enjoyment. For me it was a perspective changer.

Of course, with sufficient budget we can skip the compromises entirely and just get something like a Benchmark AHB. High output and limitless SNR.

 

[gattaca]

^^^ Yes, the ability of any system to handle the delta between average signal levels and peak signal levels is a key measurement. It is that headroom needed to deliver those peaks without clipping where the these types of power levels are required. Now once we venture into the 115+ dB range, having ultra-low distortion is only going to really matter in your mind, and typically not most guy's (or gal's) ears. Now if we are talking sub or other types of motors, it matters even less is my technical understanding. With those motors, you need lots-of-watts to drive the motor's motion or in the case of the BK's those heavy pistons.

 

[Doodski]

I cannot believe how a fair number of people here at ASR insist on judging this amplifier by the standards for a sophisticated audiophile amplifier instead of the PA/utility amplifier that it actually is.

In it's class and price range, it is a truly excellent performer and an outstanding value. And it is only an excellent foundation for an "audiophile" sound system if your goal is to accurately reproduce a live rock concert at your local stadium - or a boozy night of live music at a local bar / saloon / night club.)

Below is a photo of the first recorded music I ever purchased - a mono LP in about 1958. I still have a copy of that LP sitting a few feet away from me in my "office/media room". It's a studio production, and not not a "live" recording. I still occasionally listen to a ripped MP3 copy of that album that I downloaded.

I have no desire to reproduce anything but excellent, low-distortion HiFi sound at home - not the sound signature that reminds me of the many live nightclub gigs I have attended over the decades. Although I respect amps like the Crown for what they are and what they do, I would not trade my vintage Classé 70wpc Model Seventy stereo amp for any Crown amp.

View attachment 44048

Excellent Classe Audio gear.

 

[NTomokawa]

Classé. Made right here in Quebec. I do wonder how their products measure.

 

[Doodski]

It was not long ago we dreamed of this kind of power output never mind for US $645.00 and like amirm stated from a wall power outlet. This amp and some big Cerwin Vega or JBL's would be sweet.