Ipr2 5000/7500?

To clarify my post, we combined subs with a sister company for a large edm event. We both use srx728. Standing in front of the subs there was a clear difference between the ones running on Yamaha t5n and Itechs (yes we compensated for the difference in latency) and the ones running on the IPR amps.
All amps were at 4 ohms.
Sent from my Galaxy Nexus 4
 
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Re: Ipr2 5000/7500?

Alan Sledzieski said:
So read post 2 and 4 again. Now your post 7 makes no sence after stating what you just did. Like I said its a cheap class d amp, and will also not do what lets say a real amp will do. Yet they post these numbers of high wattage, yet they fall on theit face when pushed.
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Alan, I don't care if the amp does suck. I do care if it is being compared to amplifiers that cost 5 times as much, and I definitely care if the only thing you have to say about it is that it's a cheap piece of crap. There is a lot of really good, affordable gear - finding it is fun, and means in the future we can have more new sound folks who care.
 
Re: Ipr2 5000/7500?

They definitely don't suck but you do have to understand what the ratings mean. If you're one of those guys that believes you can get 7.5KW continuous out of a 2400W circuit (120V x 20A) you ought to fix that ;). IMO the IPRs (and most other amps) shouldn't be pushing below 4 ohm loads with EDM. You also shouldn't be exceeding the RMS rating of your subs unless you have sophisticated adjustable limiting such as the iTech has - and even then with EDM it doesn't gain you much. My "big subs" are 18" folded horns with 800w 4 ohm drivers that match up to my IPR3000 nicely (840w/ch # 4 ohms). I can push that into the red without worrying much. Of course they don't go very low so I have them properly high passed and "cheat" with a MaxxBass hardware unit to get down to 25 Hz ;).
 
Re: Ipr2 5000/7500?

Bennett, you said this,

"Alan, I don't care if the amp does suck. I do care if it is being compared to amplifiers that cost 5 times as much, and I definitely care if the only thing you have to say about it is that it's a cheap piece of crap. "

I seem to be missing where I said piece of crap, like you claimed i did?

Alan Sledzieski said:
Like I said its a cheap class d amp, and will also not do what lets say a real amp will do. Yet they post these numbers of high wattage, yet they fall on theit face when pushed.
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I shouldn't have mentioned the I techs, but the other amps we used in addition to the 2 IPR2 7500 on subs was the Yamaha T5n. They are (when Yamaha has a dealer rebate) about $300 more and don't go into protect when driving subs for an edm event. It has almost exactly the same short term power specs and maintains a much higher long term output. The 120v versions have a 30 amp plug on them, but if you are dealing with amps this size, a distro should be a given.
 
Re: Ipr2 5000/7500?

Hi Y'all,

I ordered the Crest Pro Lite 7.5 version, was told two weeks.
Got a call back, early December ship date.
Will post more after I have some time using it.

Thanks and good health, Weogo
 
Re: Ipr2 5000/7500?

Tim Padrick said:
Set the amp's limiter at -3dB from clip. Play a good recording of Also sprach Zarathustra or Toccata and Fugue in D Minor at limit. If the amp power ever dips during the pedal parts, perhaps it's not a sub amp.
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Whether an amp clips or not has NOTHING to do with whether it is a sub amp or not.

It has everything to do with whether the amp/speaker combination is proper sized for the job. If any amp is to small-then it will clip when pushed hard-no matter what amp it is.

The differences in "sub" amps are the low freq response (usually not a problem for just about any amplifier) and how long the amp can supply full output. And then how far down in level the output drops after the initial "time" period.

The later can make a big difference in SOME type of music material and not a difference in others.
 
Re: Ipr2 5000/7500?

Heck, I've got an NU3000 bridged into my TH-Minis and NU3000's have been measured at 1176w dipping to 750w after one second and going into protect after five seconds. A good match to the TH-Mini's thermal rating IMO - and I've never noticed the amp "dipping" with rock music even when the bass player doesn't bring an amp. I even used them outdoors a couple times this year just because I wanted a chance to actually open them up into the clip limiters and no prob being loud at 50 feet. Most of us guys don't need 16 Hz pedal tones at 105db back at 75 feet :?~:-?~:???:.
 
Re: Ipr2 5000/7500?

Art, thanks very much for the table. For some of the amps (other than the Lab Gruppen), the short term column shows the same duration as the medium term column. Are these typos?

Do you have detailed data for, say, 80ms up to successively longer time intervals for each impedance? I.e. can you do detailed plots of power (y axis) versus burst duration (x axis, log time) - for each amp at 2, 4 & 8 ohms?

I'd like to see amp manufacturers provide these kind of plots (for say <=0.5 % THD).


Art Welter said:
More like comparing a Lexus ISF to a Dodge Ram with a 6.7L Cummins Diesel, for subs we want low end torque more than style and handling ;^).

Ivan is right about low freq duration, 20ms is 3000 cycles at 1000 Hz (enough for any transient), but only 150 cycles at 50 Hz and 75 cycles at 25 Hz.
You need an amp that can deliver full tilt boogie for more than .02 second to maintain "punch" and impact down low.

SpeakerPower makes amps with power supplies optimized for delivering LF power at good value.

Their sub amps can deliver rated power for 3 to 6 seconds at 40 Hz, compared to .02 seconds @1K for the IPR 7500, or 2 seconds for the iT12000 HD.
That difference is not trivial, and in the real world may make a measurable 6 dB difference in actual sub SPL.
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Re: Ipr2 5000/7500?

Ivan Beaver said:
A couple of thoughts on amps in general.

It was said decades ago "What we really need is an amp that will produce 100 watts continuous and pass 20dB peaks". That would be 10,000 watts.

I totally agree with that statement-and that seems to be more the norm in todays amplifiers-large amounts of voltage swing for short periods of time.

HOWEVER_NOT all music is the same. With "normal" music the above would apply. BUT WITH modern dance/EDM/Rap etc, the low freq duration is CONSIDERABLY longer than the 20 or 40 or 80ms that have become "standard". WIth the sustained tones and very low crest factor-you need an amp that can produce power for a longer period of time.

You also need to look what happens when the amps "settle down" to a lower power and how much power they produce long term-say 3 or 4 seconds.

Now how important this is-REALLY DOES depend on the style of music and what you are doing with it.

Some of the "monster-well respected amps" just don't do as well as others when it comes to these types of signals.

Just something to look at.

It is kinda like speakers-one of the things that manufacturers don't like to talk about (what does it actually sound like at those levels-at what freq is the coverage pattern etc), and they like to focus on the short term power output.

As usual-you have to dig a bit deeper to get the real useful answer-at least as it pertains to you and your usage.

It is also quite interesting to me the number of people I have meet who have already made up their mind about something-yet have never heard it and when faced with the truth-simply refuse to acknowledge it or come up with excuses to try to defend their position-however wrong it may be.

Listen to things with an open mind and THEN make a decision. But there is so much "brain washing" and "wanting to hang with the crowd", that many people put their blinders up real quick.
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+1.. To reinforce a point made by Ivan, people have eventually learned to come to terms with the fact that loudspeakers handle far more peak or transient energy than continuous, but are shocked when power amps mimic that behavior. In an ideal world the power amp would deliver the same power vs. time profile as the loudspeaker it is connected to.

Of course nothing in life is quite this simple and I have watched the evolution of reduced duty cycle amps play out over decades. This was dominantly influenced by cost, as customers happily bought cheaper amps that didn't put out full power 24x7. Another of my popular whines is the lack of a comprehensive, easily understood (by unwashed consumers) spec for duty cycle. I am not holding my breath for this since I appreciate the difficulty and unintended consequences** of giving the marketplace another data sheet spec that so few will understand.

JR

** the unintended consequence is that this too will become in play for specsmanship in marketing, and then designs will be altered purely for marketing purposes (think back to damping factor and slew rate, and.....).
 
Re: Ipr2 5000/7500?

Alan Sledzieski said:
JR,

Whats the difference between the Ipr5000 and the crest 5.0 Are they the same guts internally, as far as output.
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From what I understand-the circuitry is the same-but the Crest is a bit "Beefier" in a number of ways. So the basic output specs (as on the spec sheet) would be the sameI have not confirmed this.

Including more heatsink area for the outputs (for harder more high temp operation), more power supply capacitance (for tighter/longer sustained bass) etc.
 
Re: Ipr2 5000/7500?

Alan Sledzieski said:
JR,

Whats the difference between the Ipr5000 and the crest 5.0 Are they the same guts internally, as far as output.
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I have been off that island far too long to have any specific knowledge about this. I know people who know but do not regularly talk with them, and if I do I am not inclined to ask them mundane stuff like this.

In general when a parent company has multiple brands (like Peavey and Crest) it is just common sense to share a technology platform between them. The Crest brand can attract a higher price customer and will likely get some added features. While not what most people think of as features, these could involve larger PS caps, more heatsink, etc.. (yes those are features).

I would suggest asking them, and if that is not productive a close study of the FAB sheets (Features, advantages, and benefits). If marketing is rational at all any money spent on added features will be touted in the FAB.

Since I have been out of the loop for over a decade I have no idea how disciplined the current crop of product managers are, or their current brand management strategy.

JR

PS: I don't really care either...
 
Re: Ipr2 5000/7500?

Ivan Beaver said:
From what I understand-the circuitry is the same-but the Crest is a bit "Beefier" in a number of ways. So the basic output specs (as on the spec sheet) would be the sameI have not confirmed this. Including more heatsink area for the outputs (for harder more high temp operation), more power supply capacitance (for tighter/longer sustained bass) etc.
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That is what a Peavey engineer told me - plus perhaps beefier outputs on the Crest. Also I believe the Crest DSP version has more of the features of the Waves DSP chip "turned on" than the Peavey version. FWIW the power supply was designed by Peavey and the amp by Crest as a joint project.
 
Re: Ipr2 5000/7500?

I am using the 5000 as I type, running 4 2x18 PAS CB2 subs in a 500+ cap room that I owned for a bit and worked in for 4 years. This replaced 4 Carver PM 2.0's running mono one to a sub. All seems good. I gave the amp it's own 20 amp circuit.
Running 4 SLS 96O's from 1 "B" Inuke 3000. Loud jam band.
 
Re: Ipr2 5000/7500?

I know this is an old thread however some comments on here make little sense. Amplifiers in general take garbage in and put garbage out if they work correctly. I have had Crown I techs and Macro Techs, Crest Pro 9200s and various CCs and now own several ProLite 7.5s. Honestly they all work well, with some (Like the 7.5) being very well suited for low end duty despite the earlier comments on this forum. Rather than bridging amps for 3 to 4k per sub, I just run larger amps with good 4 ohm power to my VR 218 boxes (Up to 6 per side). Bi wiring this setup keeps wire gauge sufficient and of course shunts any back emf at the output terminals at the amp. In these instances the 7.5s serve me well, both in efficiency, sound quality and they are good on my back. As far as the DSP models I am not of any use, I prefer to stay away from the DSP versions of any amp and just run outboard processing such as a BSS or Digitool. Guess I am old school.
 
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