Crown Xti4002 Pro Stereo Amplifier Review

[Alice of Old Vincennes]

Rugged, robust and powerful beast Ok, but In my opinion exclusively for heavy duty stage works for rock/hiphop and so.

Nothing here for domestic or monitoring use, even for passive subs. There are many better alternatives, and active subs includins DSPs are more convenient anyway and some are very very powerful too.

Relatively disappointing measurements for a brand like Crown : poor SNR and distorsion, polluted signals, and rather severe "plocs" on/off (I hate that, and hps hate that too !).

As for stage sound, it's easy to find much better at Powersoft, RAM, Labgruppen, Yamaha and others, at no extravagant prices (a little more expensive, but quite worthy the extra money for amps built for many years). So I don't undersand why Amir recommends it, pure power doesn't do it all.

Crown doesn't have a chance. Maybe they should hire you as a consultant.

 

[Deleted member 48726]

This Crown amp is worthless as a home hi-fi amp, and I rated as if I were considering it for that purpose. (Personally have no application for an amp to suitable to power a shopping mall sound system.)

This amp will sound bad to anyone who listens compared to the latest Purifi, Hypex, or ICEpower amps -- or even those made in the last decade. Sound difference deniers are going to have a hard time with this one.

I voted excellent just to statistically counter your B.S.

 

[Hayabusa]

I don't believe you.

That's a very useful response..
You don't believe all?
If not, what is it you don't believe?

 

[Music1969]

Seems a troll has joined this thread.

Or a Crown engineer

 

[Alice of Old Vincennes]

That's a very useful response..
You don't believe all?
If not, what is it you don't believe?

I don't believe everybody you know can hear a difference. I don't believe that PA crowd was transporting a ton of amps requiring additional portable generators costing $$$$.

 

[Alice of Old Vincennes]

Seems a troll has joined this thread.

Or a Crown engineer

I keep reading the same cut and paste responses.

 

[ocinn]

I don't believe everybody you know can hear a difference. I don't believe that PA crowd was transporting a ton of amps requiring additional portable generators costing $$$$.

Yeah….

Ok. Let me dumb this down. Back in the day, before lightweight and efficient class D amplifiers were a thing, huge touring acts used to bring 40 racks of massive Class A/B, G, H amplifiers to run their subwoofers.

As high performance class D amplifiers were introduced, they were able to replace their 4+ U legacy amps with 1-2u class D amps. The loss of sustained output power (irrelevant for anything but electronic music) was easily offset with just adding more amplifiers (now negligible rack space) and the efficiency boost made power requirements practically irrelevant. This saved them a lot of money on freight costs, generator rental, labor, and power distro.

So they sold off their old Class A/B/G/H amps. Then it was shown that these older, inefficient, and heavy amplifiers could sustain constant output far more consistently than something like a Powersoft K10. So individuals running (comparatively) small systems which only need 1-2racks of amps, purchased them used for dirt cheap, and got the benefit of fantastic sustained output with the caveats of higher weight and power draw (both irrelevant on smaller scale PAs).

To refute your point of “it’s not subjectively audible” lets look at the data in the paper I cited in my original post. After 1 second of sustained output, a K10 will lose 4.7db of output. After 11s it will lose 7.6db. If that is not subjectively audible to you I suggest you get your ears checked.

Hope that’s digestible enough for you. I am a professional in the live entertainment field and have zero allegiances with any manufactures or companies. Just because someone has knowledge of objectively proven performance, doesn’t mean they are an employee of a company.

For what it’s worth I use modern Class D amps exclusively at work and one of the main challenges in system deployment (especially in electronic music with massively long sustained notes) is to ensure you have enough amplifiers that they never go into power sag/compression. I.e we want all amplifiers to only need to output what their max power draw * efficiency factor is. Any more than that we start to get into output sag as the power supplies cannot keep up which ruins tonality of the system

Your accusation of a troll is ironic because statements such as “I don’t believe you” are much more in line with troll behavior than anything I said.

 

[ocinn]

I doubt you can hear any difference. Amp will control any speaker.

You are correct in that this level of objective THD+N performance is irrelevant in live sound contexts due to ambient noise dominating over reasonable distortions and amplifier noise. But 764w of clean output power is abysmal in live sound contexts. Wattage:SPL is logarithmic.

To give an example this amplifier driving a Danley SH96HO would be leaving 3.7db of clean output on the table.

However, the power output of this amp means it should experience minimal power compression when driven by a 120v@15a power feed. (0.8db output sag based on max output of amp minus technical continuous draw limit of power source, 1440w*~0.85 amp efficiency)

 

[Bugal1998]

Hopefully someone will offer them for testing. I considered buying one myself for testing but even dealer cost is way up there.

@amirm I've offered an I-tech 5000hd for testing on a number of occasions (before you had your new dummy load), and the offer still stands if there's interest.

 

[Alice of Old Vincennes]

Yeah….

Ok. Let me dumb this down. Back in the day, before lightweight and efficient class D amplifiers were a thing, huge touring acts used to bring 40 racks of massive Class A/B, G, H amplifiers to run their subwoofers.

As high performance class D amplifiers were introduced, they were able to replace their 4+ U legacy amps with 1-2u class D amps. The loss of sustained output power (irrelevant for anything but electronic music) was easily offset with just adding more amplifiers (now negligible rack space) and the efficiency boost made power requirements practically irrelevant. This saved them a lot of money on freight costs, generator rental, labor, and power distro.

So they sold off their old Class A/B/G/H amps. Then it was shown that these older, inefficient, and heavy amplifiers could sustain constant output far more consistently than something like a Powersoft K10. So individuals running (comparatively) small systems which only need 1-2racks of amps, purchased them used for dirt cheap, and got the benefit of fantastic sustained output with the caveats of higher weight and power draw (both irrelevant on smaller scale PAs).

To refute your point of “it’s not subjectively audible” lets look at the data in the paper I cited in my original post. After 1 second of sustained output, a K10 will lose 4.7db of output. After 11s it will lose 7.6db. If that is not subjectively audible to you I suggest you get your ears checked.

Hope that’s digestible enough for you. I am a professional in the live entertainment field and have zero allegiances with any manufactures or companies. Just because someone has knowledge of objectively proven performance, doesn’t mean they are an employee of a company.

For what it’s worth I use modern Class D amps exclusively at work and one of the main challenges in system deployment (especially in electronic music with massively long sustained notes) is to ensure you have enough amplifiers that they never go into power sag/compression. I.e we want all amplifiers to only need to output what their max power draw * efficiency factor is. Any more than that we start to get into output sag as the power supplies cannot keep up which ruins tonality of the system

Your accusation of a troll is ironic because statements such as “I don’t believe you” are much more in line with troll behavior than anything I said.

You changed things with the qualifier "hugh touring acts." Different animal.

 

[Hayabusa]

You changed things with the qualifier "hugh touring acts." Different animal.

He did not change things. You wrongly assumed it was not about huge touring acts and called him a 'lair' by bluntly saying "I don't believe you".
An apology to ocinn would be appropriate.

 

[Tovarich007]

Yeah….

Ok. Let me dumb this down. Back in the day, before lightweight and efficient class D amplifiers were a thing, huge touring acts used to bring 40 racks of massive Class A/B, G, H amplifiers to run their subwoofers.

As high performance class D amplifiers were introduced, they were able to replace their 4+ U legacy amps with 1-2u class D amps. The loss of sustained output power (irrelevant for anything but electronic music) was easily offset with just adding more amplifiers (now negligible rack space) and the efficiency boost made power requirements practically irrelevant. This saved them a lot of money on freight costs, generator rental, labor, and power distro.

So they sold off their old Class A/B/G/H amps. Then it was shown that these older, inefficient, and heavy amplifiers could sustain constant output far more consistently than something like a Powersoft K10. So individuals running (comparatively) small systems which only need 1-2racks of amps, purchased them used for dirt cheap, and got the benefit of fantastic sustained output with the caveats of higher weight and power draw (both irrelevant on smaller scale PAs).

To refute your point of “it’s not subjectively audible” lets look at the data in the paper I cited in my original post. After 1 second of sustained output, a K10 will lose 4.7db of output. After 11s it will lose 7.6db. If that is not subjectively audible to you I suggest you get your ears checked.

Hope that’s digestible enough for you. I am a professional in the live entertainment field and have zero allegiances with any manufactures or companies. Just because someone has knowledge of objectively proven performance, doesn’t mean they are an employee of a company.

For what it’s worth I use modern Class D amps exclusively at work and one of the main challenges in system deployment (especially in electronic music with massively long sustained notes) is to ensure you have enough amplifiers that they never go into power sag/compression. I.e we want all amplifiers to only need to output what their max power draw * efficiency factor is. Any more than that we start to get into output sag as the power supplies cannot keep up which ruins tonality of the system

Your accusation of a troll is ironic because statements such as “I don’t believe you” are much more in line with troll behavior than anything I said.

What do you mean by "losing sustained output" ? You mean full power output ?
Anyway, I am quite surprised : how can an amp can lose more than 4 dB (that is more than 1/2 of its power ! ) in only 1 second and another 4 dB in 10 more seconds ? I'm not linked to any firm or distributor, I am a hifi and recording amateur not involved in PA or large live sound applications, but I am surpised that a brand like Powersoft (or others, including Crown) could design so poor power amps, I am quite skeptical about your statement.

On the other hand, to reply to other members, I maintain that I consider not optimal at all the measured performances of the Crown XTI 4002. It is certainly a rather good powerful amp for PA and live sound, at very high SPL levels for rock/pop music, probably you couldn't find much audible differences, but at more sustainable volume and for more subtle muiscal genres, I doubt it could compete for precision and finesse with Hypex, Purifi, even Icepower and other more refined class D or AB,.
There are other series at Crown that are better than this one anyway.

 

[Hayabusa]

What do you mean by "losing sustained output" ? You mean full power output ?
Anyway, I am quite surprised : how can an amp can lose more than 4 dB (that is more than 1/2 of its power ! ) in only 1 second and another 4 dB in 10 more seconds ? I'm not linked to any firm or distributor, I am a hifi and recording amateur not involved in PA or large live sound applications, but I am surpised that a brand like Powersoft (or others, including Crown) could design so poor power amps, I am quite skeptical about your statement.

If you look at the specs of the K10 this does not sound unlikely.
For instance it's main input current limit is 45Amps would be around 5kw at 110volts.
The K10 peak power is 12kw, what will only happen when its power caps are fully charged.
Power supply caps could easily bridge in the seconds range what would correlate with what ocinn was saying.

 

[Tovarich007]

In every amp, peak power is obtained for only a vey short time and with the caps charged, it's not only true with this amp.
Powersoft K10's peak current non bridged is 125A, not 45, so your calculation is not correct.
Of course, good old heavy linear power supplies, if they are well done (not always the case), have some headroom and their large capacitors (if well dimensioned) keep relatively more current reserve than switching power supplies. But this has quite a cost and a weight.

Anyway, 12 Kw or even 5 kw divided by 2 or 4 for just one amp in a large live sound operation, it's more than enough to damage compression drivers and, more preoccupying, lots of human ears as well
So, is this a real problem in the real world ? I'm not sure and still not convinced.

 

[Hayabusa]

In every amp, peak power is obtained for only a vey short time and with the caps charged, it's not only true with this amp.
Powersoft K10's peak current non bridged is 125A, not 45, so your calculation is not correct.

INPUT current from the mains.. This is the spec..

https://www.powersoft.com/wp-content/uploads/2019/01/powersoft_KSeries_uguide_mul.pdf

 

[Deleted member 48726]

What do you mean by "losing sustained output" ? You mean full power output ?
Anyway, I am quite surprised : how can an amp can lose more than 4 dB (that is more than 1/2 of its power ! ) in only 1 second and another 4 dB in 10 more seconds ? I'm not linked to any firm or distributor, I am a hifi and recording amateur not involved in PA or large live sound applications, but I am surpised that a brand like Powersoft (or others, including Crown) could design so poor power amps, I am quite skeptical about your statement.

On the other hand, to reply to other members, I maintain that I consider not optimal at all the measured performances of the Crown XTI 4002. It is certainly a rather good powerful amp for PA and live sound, at very high SPL levels for rock/pop music, probably you couldn't find much audible differences, but at more sustainable volume and for more subtle muiscal genres, I doubt it could compete for precision and finesse with Hypex, Purifi, even Icepower and other more refined class D or AB,.
There are other series at Crown that are better than this one anyway.

What is this ""precision" and "finesse" features you talk about? I mean, if an amp has a straight frequency response it reproduces the signal like it should. -Transparent. Then it is down to noise and distortion which beneath a certain level isn't audible anyway.

IR to "sustained output" surely this relates to the difference between "peak" and "continuous" of which A/B based amps excel in the way of how they have more or less stored energy in their main filter capacitors.

 

[ocinn]

What do you mean by "losing sustained output" ? You mean full power output ?

 

[Deleted member 48726]

View attachment 318199

So, that's actually thermal limited, right? -Looks like it's due to temperature.

 

[ocinn]

So, that's actually thermal limited, right? -Looks like it's due to temperature.

Not exclusively, no. But that’s a factor.

Ironically the K10 actually can hold continuous power without noticeable thermal issues. The peak:cont ratio is atrocious but if you treat it like a 1500w amplifier, it can hold it, at least at 120v which is what they were tested at.

My “issue” with class D subwoofer amps is not their performance but in fact their marketing. The K10 is marketed as as 12kw amp. In reality it can only do 7.5kw and then quickly falls down to its powerdraw*efficiency factor output (1500w)

A crest 100001, for example, will actually do 10kw all day long no limiting no thermals no PSU compression assuming you give it 2x 30a@240v lines like it calls for.

Thus why I stand by my point that for small PA systems, you simply cannot beat a big old school powerhouse amplifier. Once you start getting into the multiple racks, dedicated commercial generator/3phase territory. Things change. Then a “overkill” (based on specs) deployment of class D amps can have an advantage (volume, weight, efficiency/current, etc)

But I always view them as their long term cont output, not their rated spec. The K10 is a 1500w amp in my eyes, at least on 120v, etc..

 

[Willem]

Since this forum is largely concerned with domestic audio I think it may be interesting to post measurements of a more modestly powered (2x350 watt) Yamaha P3500s: https://www.homecinema-fr.com/forum...mpli-yamaha-p3500s-mise-a-jour-t30056383.html In practice, the fan of this amplifier never came on during the tests. Encouraged by these results I bought a 300 euro 2x250 watt Yamaha P2500s for my son, and here too, in home use the fan never kicks in. Do I need to say that it sounds great (i.e. like any other decent amp)?