Crown Xti4002 Pro Stereo Amplifier Review

[SuicideSquid]

No, some of them read these measurements

They need to be held accountable for such crap performance

Maybe one day @MC_RME will get into amps and show the pro companies how it should be done

In what respect does this amp have "crap" performance?

It is made for driving speakers in large venues at very loud levels. It is not meant to be used at low levels in a home environment. For its intended application, the performance is excellent.

If you take a 125wpc home amplifier and try to drive a 2ohm professional PA speaker at 100+dB volume levels for six hours straight, either that amp is just going to go into protection mode and not work at all, or it's going to overheat and die in short order, while producing very high levels of distortion in the process. By professional amplifier standards, that's crap performance.

 

[fpitas]

Honest Q: How many active stages with SINAD of -71dB can your audio-chain handle before it becomes audible to you?

Probably quite a few.

 

[ocinn]

I know that the pro amp companies use class D solutions, but last I looked it was for (relatively) lower power applications.

I work full-time in live sound, Class D/switching amps are industry standard, period these days.

32,800W (4ch) out of 2U enclosure - https://www.powersoft.com/en/products/touring-amps/x-series/x4l#specifications

20,800W (16ch) out of 2U - https://www.l-acoustics.com/products/la7-16/ (note: L'Acoustics notoriously under-rates their products in almost every aspect)

This is a good read: https://forums.melaudia.net/attachment.php?aid=30627
Note Page 22's graph on power vs. time.

I will say subjectively (and every professional I've ever met will agree), no amplifier on subwoofers works as well as a big, old, heavy, inefficient A/B amp with a huge transformer and enough capacitors to instantly kill 15 people (assuming the same total watts vs a Class D solution). Unfortunately, they are impractical to tour with and require far larger generator rentals ($$$), so there is no market for them apart from individuals who run their own system (mostly dub/bass/genre sound systems which need to play 35hz full-scale for 3 minutes straight with zero output sag).

For reference, the most powerful non-switching amplifiers were the:

1) Crown Macro-Tech 10000 (3 phase, designed for <1ohm subwoofer arrays, specs, page 30 as well as this sheet)
2) Crest 100001 (specs, AFAIK, truly class A/B linear supply, no rail switching!!)
3) Void Infinite 8 Mk2 (class G, specs also independent bench test)
4) Crown Macro-Tech 5000VZ/5002VZ (class G, specs)
5) EV P3000 (true class A/B, linear supply, no rail switching, specs)

Honorable/borderline not qualifiable mentions (no headroom, so no benefits/merits):

Matrix XT6004 (SMPS single rail voltage, Class A/B)
The MC2 E45 and Lab Gruppen 20K44 both use tracking rail SMPS. Lab's Class TD implementation works quite a bit better than MC2's traditional Class H, which is how it manages 20kw while still using A/B output stages.

Edit: The Lab Gruppen design is so good, that it's been successfully cloned. And yes these amps actually do make all that power for that price. It's incredible.

https://www.aliexpress.us/item/2251832706148644.html

 

[pseudoid]

Two quasi-OT questions:
1. Are there any similar forums as ASR, which cater to professional audio gear shakedowns?
2. Should ASR branch-out further to continue testing such gear?

 

[Bird_of_Hermes]

I work full-time in live sound, Class D/switching amps are industry standard, period these days.

32,800W (4ch) out of 2U enclosure - https://www.powersoft.com/en/products/touring-amps/x-series/x4l#specifications

20,800W (16ch) out of 2U - https://www.l-acoustics.com/products/la7-16/ (note: L'Acoustics notoriously under-rates their products in almost every aspect)

This is a good read: https://forums.melaudia.net/attachment.php?aid=30627
Note Page 22's graph on power vs. time.

I will say subjectively (and every professional I've ever met will agree), no amplifier on subwoofers works as well as a big, old, heavy, inefficient A/B amp with a huge transformer and enough capacitors to instantly kill 15 people (assuming the same total watts vs a Class D solution). Unfortunately, they are impractical to tour with and require far larger generator rentals ($$$), so there is no market for them apart from individuals who run their own system (mostly dub/bass/genre sound systems which need to play 35hz full-scale for 3 minutes straight with zero output sag).

For reference, the most powerful non-switching amplifiers were the:

1) Crown Macro-Tech 10000 (3 phase, designed for <1ohm subwoofer arrays, specs, page 30 as well as this sheet)
2) Crest 100001 (specs, AFAIK, truly class A/B linear supply, no rail switching!!)
3) Void Infinite 8 Mk2 (class G, specs also independent bench test)
4) Crown Macro-Tech 5000VZ/5002VZ (class G, specs)
5) EV P3000 (true class A/B, linear supply, no rail switching, specs)

Honorable/borderline not qualifiable mentions (no headroom, so no benefits/merits):

Matrix XT6004 (SMPS single rail voltage, Class A/B)
The MC2 E45 and Lab Gruppen 20K44 both use tracking rail SMPS. Lab's Class TD implementation works quite a bit better than MC2's traditional Class H, which is how it manages 20kw while still using A/B output stages.

Interesting, before I gave up on buying a Kappa 9 a few years ago (instead I got a much easier Kappa 8.1) I didn’t think that a Class D amp could handle its sub 1 ohm areas.

I suppose the answer is: get a pro amp and don’t worry about distortion

 

[DanielT]

I don't understand the reasoning behind that statement. Your ears can hear SINAD beyond 70dB?

Apparently.

Honest Q: How many active stages with SINAD of -71dB can your audio-chain handle before it becomes audible to you?

My #39 in the thread. I think that study was so interesting that I will take it again. The higher the frequency, the more sensitive we are to distortion. Those who participated in the study in the link below, at 10 kHz distortion was detected at 40-45 dB (1-0.5%) .

At lower frequencies, well a completely different ball game so to speak. "..mid-bass at 280 Hz and lower, the noise can be around -14 dB (20% distortion), about half as loud as the music itself, before we hear it....At 40 Hz, listeners accepted 100% distortion before they complained. The noise test tones had to reach 8,000 Hz and above before 1% distortion became audible, such is the masking effect of music.."

How Much Distortion Can We Hear With Music?

How much distortion can we hear with music? An experimental study at Axiom.

www.axiomaudio.com

 

[Gorgonzola]

My #39 in the thread. I think that study was so interesting that I will take it again. The higher the frequency, the more sensitive we are to distortion. Those who participated in the study in the link below, at 10 kHz distortion was detected at 40-45 dB (1-0.5%) .

At lower frequencies, well a completely different ball game so to speak. "..mid-bass at 280 Hz and lower, the noise can be around -14 dB (20% distortion), about half as loud as the music itself, before we hear it....At 40 Hz, listeners accepted 100% distortion before they complained. The noise test tones had to reach 8,000 Hz and above before 1% distortion became audible, such is the masking effect of music.."

How Much Distortion Can We Hear With Music?

How much distortion can we hear with music? An experimental study at Axiom.

www.axiomaudio.com

Humm ... well I don't listen for distortion. What I listen for is detail and resolution, also bass that sounds like actual bass instruments such as double bass, bassoon, bass drum. Somehow, whether or not I can prove it, I believe that I and others can hear reductions in, e.g. resolution, before anything that we could identify as distortion per se.

 

[ocinn]

Are there any similar forums as ASR, which cater to professional audio gear shakedowns?

DIY Audio, AVS forum, Speakerplans, and ProSoundWeb all have great sections for professional gear discussions.
r/LiveSound is also a great resource for implementation advice. Lots of seasoned vets in there, but not a lot of gear knowledge beyond the basics.

@/notnyt (AVS forum) has been dyno'ing PA amps since like 2014 or so if I recall. A lot of us pro/industry ASR members are in the above spaces as well.

2. Should ASR branch-out further to continue testing such gear?

Yes, but I think we should also take some time to learn what the needs and requirements are in professional spaces for amps, speakers, etc...

There was a recent thread where a member was complaining about how his large 3 way active PA speakers (that he uses for playing live shows) were too heavy, and until I and a few others stumbled across the thread, members were unironically recommending Kef LS60, Genelec S360A, DML speakers, Philharmonic BMR, Devialet Phantom, ... for live gig PA use, when the correct answer was to downsize on the tops and add a subwoofer.

I feel like ASR members as a whole have an achilles' heel surrounding all aspects of live audio (acoustics (especially bass), implementation, routing, cost/benefit balances, etc...). I wrote a comment with some books that I believe are essentially required reading to begin to understand this segment, see this hyperlink.

You quickly realize how far "optimal live sound implementation" diverges from the home audio stuff we discuss here. For example, this is a perfectly optimized subwoofer array but most here would probably think they were just unloaded from the truck and not setup yet.

 

[amirm]

Two quasi-OT questions:
1. Are there any similar forums as ASR, which cater to professional audio gear shakedowns?
2. Should ASR branch-out further to continue testing such gear?

I can only speak to Custom Integration channel. The de-facto forum for that is Remote Central. But no, it is just a discussion forum and no reviews.

As for us, I will continue to measure these as long as members send them. They have definite use for subwoofer duty. And if we find a quiet, high performance one, for normal hi-fi use as well.

 

[amirm]

@/notnyt (AVS forum) has been dyno'ing PA amps since like 2014 or so if I recall.

I checked and seems he stopped posting around 2017. We are not going to see true performance of these amps with "dyno" testing anyway.

 

[IAmAlwaysSerious]

Honest Q: How many active stages with SINAD of -71dB can your audio-chain handle before it becomes audible to you?

It depends on quite a lot, actually. If that's 71dB dominated by noise, probably very few stages (one or two stages -depending on the exact component mix- with sensitive speakers).
For comparison, I can hear the noise floor of my THX Onyx with very sensitive IEMs in a dead quiet room.
If that had a SINAD of 71dB instead of ~105dB at max output and was noise dominated, then I'd be able to hear that noise pretty easilly through a pair of moderately sensitive IEMs in an average living room.

Distortion dominating? You'd need several components like that and very good speakers before you noticed anything.
There could be outlier situations where that could be noticeable at fairly high listening volumes. It's not even that hard to imagine such a situation, but it wouldn't be typical.

 

[ocinn]

I checked and seems he stopped posting around 2017. We are not going to see true performance of these amps with "dyno" testing anyway.

Ah. It was a good test for 5kw++ PA amplifiers (subwoofer use). I remember when he started posting the results to the (at the time) most popular subwoofer amplifiers on that forum (inukes etc) got exposed for vastly over-rating not only their continuous but also their burst power. So there's merit to it in that use case, even if it's rudimentary by our standards. He has a Virtins RTX6001 so definitely capable of more in-depth measurements.

Peniku8 (also on AVS, not sure why this thread isn't crossposted there) built a load box as well.

Rob's Amp tests

I built a loadbank to bench-test audio amplifiers on a resistive load. The loadbank consists of 16 3KW 220V heating elements, which allows me to test any combination of 8 8Ohm clusters for up to 4 channels.More on the loadbank in this post. Results: Sanway FP-13000 (MKI) t.amp TSA-1400 t.amp TSA4...

data-bass.ipbhost.com

 

[Dan Clark]

Surprising how the more affordable Crown XLS appears to have slightly better SINAD compared to the XTi.
But with that reactive load test and a wide-voltage power supply, it's pretty much bulletproof to any tough scenarios out there.

And with the ante upped, would it be possible to see maybe the i-Tech HD or MacroTech in the future?

I have some XLS 1502s and the downside is they force an AD-DA cycle, there's no digital input.

We replaced them with some Rockville D14s for the bass amps, WAY more power and way lower cost, and then for the highs we put in dual 500+500W Hypex modules for the mids and tops. System plays way louder and tops are in a different league for clarity with the Hypex's...

 

[Chrispy]

I have some XLS 1502s and the downside is they force an AD-DA cycle, there's no digital input.

We replaced them with some Rockville D14s for the bass amps, WAY more power and way lower cost, and then for the highs we put in dual 500+500W Hypex modules for the mids and tops. System plays way louder and tops are in a different league for clarity with the Hypex's...

Send Amir one of those Rockvilles....

 

[robwpdx]

I work full-time in live sound, Class D/switching amps are industry standard, period these days.

32,800W (4ch) out of 2U enclosure - https://www.powersoft.com/en/products/touring-amps/x-series/x4l#specifications

20,800W (16ch) out of 2U - https://www.l-acoustics.com/products/la7-16/ (note: L'Acoustics notoriously under-rates their products in almost every aspect)

This is a good read: https://forums.melaudia.net/attachment.php?aid=30627
Note Page 22's graph on power vs. time.

I will say subjectively (and every professional I've ever met will agree), no amplifier on subwoofers works as well as a big, old, heavy, inefficient A/B amp with a huge transformer and enough capacitors to instantly kill 15 people (assuming the same total watts vs a Class D solution). Unfortunately, they are impractical to tour with and require far larger generator rentals ($$$), so there is no market for them apart from individuals who run their own system (mostly dub/bass/genre sound systems which need to play 35hz full-scale for 3 minutes straight with zero output sag).

For reference, the most powerful non-switching amplifiers were the:

1) Crown Macro-Tech 10000 (3 phase, designed for <1ohm subwoofer arrays, specs, page 30 as well as this sheet)
2) Crest 100001 (specs, AFAIK, truly class A/B linear supply, no rail switching!!)
3) Void Infinite 8 Mk2 (class G, specs also independent bench test)
4) Crown Macro-Tech 5000VZ/5002VZ (class G, specs)
5) EV P3000 (true class A/B, linear supply, no rail switching, specs)

Honorable/borderline not qualifiable mentions (no headroom, so no benefits/merits):

Matrix XT6004 (SMPS single rail voltage, Class A/B)
The MC2 E45 and Lab Gruppen 20K44 both use tracking rail SMPS. Lab's Class TD implementation works quite a bit better than MC2's traditional Class H, which is how it manages 20kw while still using A/B output stages.

Edit: The Lab Gruppen design is so good, that it's been successfully cloned. And yes these amps actually do make all that power for that price. It's incredible.

https://www.aliexpress.us/item/2251832706148644.html

Thanks for this. In outdoor concert, there is a lot of ambient audience noise. Even in a concert hall, there is all kinds of audience rustling, and hopefully not HVAC noise. So what is the noise floor in the listening environment for these amps? Probably high.

My home is a little noisy with my neighbor's outdoor unit. The quietest room away from windows is about 36dBA. A recording studio control room would be quieter, under 30dB. So for a quiet home or a recording studio, that super low SNAD amplifiers we discuss on ASR may have advantages.

For completeness, the noise floor in most vehicles is significant, which is an argument against ATMOS in moving or the engine-on vehicles. I guess you could go out in the wilderness and listen to ATMOS in your parked car!

 

[DanielT]

Humm ... well I don't listen for distortion. What I listen for is detail and resolution, also bass that sounds like actual bass instruments such as double bass, bassoon, bass drum. Somehow, whether or not I can prove it, I believe that I and others can hear reductions in, e.g. resolution, before anything that we could identify as distortion per se.

If we take the bass part then.Couldn't Crown Xti4002 give you the bass you're looking for? Crown Xti4002 has straight FR, is load independent, inaudible distortion in the bass area, has a lot of power and can hold bass drivers in an iron grip.

For my own part, the Crown Xti4002 would easily be sufficient for use as a full-range amplifier. Unfortunately speakers can easily have 30 times more distortion than Crown Xti4002. So the speakers had worried me more in that case. Especially if it was speakers with high tweeter distortion because we are most sensitive to distortion in that frequency range.

 

[ocinn]

In outdoor concert, there is a lot of ambient audience noise. Even in a concert hall, there is all kinds of audience rustling, and hopefully not HVAC noise. So what is the noise floor in the listening environment for these amps? Probably high.

I’ve been saying this for the longest time. “Good” (in our eyes) Noise floor performance is irrelevant in pro audio.

Even quiet wine bars have an ambient noise floor which would drown out any (non-broken) amplifier’s hiss.

Clubs/festivals? Forget it. Ambient noise is >>~80db(A) and the system is ran at ~104(A).

Far more important is behavior as they approach limiting/clipping. Amplifiers which do not have networking or programmable limiters, and go into harsh high-order distortion at the limit are very audible. Amplifiers that can play cleanly to the point that your transducers are the limiting factor are the correct choice

Also any modern touring amp (L’Acousrics, D&B, etc) have fantastic internal limiting where you can set voltage/VA limitations and it will actively keep it self out of distortion by referencing the amplified outputs.

 

[Gorgonzola]

If we take the bass part then.Couldn't Crown Xti4002 give you the bass you're looking for? Crown Xti4002 has straight FR, is load independent, inaudible distortion in the bass area, has a lot of power and can hold bass drivers in an iron grip.

For my own part, the Crown Xti4002 would easily be sufficient for use as a full-range amplifier. Unfortunately speakers can easily have 30 times more distortion than Crown Xti4002. So the speakers had worried me more in that case. Especially if it was speakers with high tweeter distortion because we are most sensitive to distortion in that frequency range.

For my part I'm quite content with my Purifi 1ET400A-based amplifier which as plenty of power given my speakers in my listening environment. Looking at the audiophile amps out there, the Purifi amp is a tremendous bargain and personally have no need to consider an amp like the Crown Xti4002. Versus the Purifi, the Crown has significantly higher noise and distortion, and looking at the harmonic spectrum Amir has provide, I quite put off by the forest of higher order harmonics that amp is creating. IMO, these distortion are, at least, going to produce a audibly "grungy" top end.

What is an interesting question is the extent that one component if one's system, especially one inherently higher in distortion, can entirely mask the the distortion in another, perhaps less inherently distorting component. My answer would be: not entirely. This is something I've always experienced and believe. Presently I'm lucky to have nice speakers with very low distortion, (Scan Speak), drivers.

 

[prerich]

This amp is maybe near lethal or could be lethal with this kind of DC voltage. Wow!

This may be the first time (that I can remember) that you've stated the recommended use of an amplifier (subwoofer, PA) and classified it as such (target customer). Bravo on an excellent review. Yes...the Crowns produce a lot of juice - I use one on my subs.

 

[Rottmannash]

I checked and seems he stopped posting around 2017. We are not going to see true performance of these amps with "dyno" testing anyway.

There's a guy on YT who measures mostly car amps with a "Dyno". How is using this different from the AP you use @amirm?