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[Kashif Hudson]

We currently have a number of Ma12000i. They behave poorly with mid to high frequency duty. The clarity and precision just falls apart. We even A/B'ed the Crowns against Mackie m1400 in stereo and even with less power, the Mackies outperformed the crowns by a wide margin. Does anyone know if this is also the case with the 9000i & 5000i? Do they also suffer the same on mid-hi duty? Please help before we make a regrettable purchase to power our Community RS880's

Thank to all,

Hudson

[Tim McCulloch]

What is "suffer" as it applies to an amplifier?

[Kashif Hudson]

Please forgive my usage of suffer In regards to an amplifier if it is incorrect. Is it possible that the 12000i may be struggling or lacking in its ability to accurately reproduce mid or high frequency signals and is this phenomenon also present in the 9000i & 5000i. 2 of our 12000i were bought brand new and the other two purchased from another psw member. They all exhibit the same harsh high frequency behavior. There must be someone that understands amplifiers that can better explain what is happening so my question does not get ridiculed or lost in translation.

[Ray Aberle]

Please forgive my usage of suffer In regards to an amplifier if it is incorrect. Is it possible that the 12000i may be struggling or lacking in its ability to accurately reproduce mid or high frequency signals and is this phenomenon also present in the 9000i & 5000i. 2 of our 12000i were bought brand new and the other two purchased from another psw member. They all exhibit the same harsh high frequency behavior. There must be someone that understands amplifiers that can better explain what is happening so my question does not get ridiculed or lost in translation.

Kashif, can you give a bit more details as to what else is in your system?

I have a 9000i that I use for STX815M wedges, and it sounds great across all frequencies. (Purchased brand new when they were first released in 2008.) So, perhaps there is something in your system that is hampering the ability of your 12K - and if we know what else you're working with maybe something will jump out at us.

-Ray

[Kashif Hudson]

Thank you for attempting to help Ray. There are only two pieces of equipment before the crowns. A pioneer Djm-5000 mixer and a Lake Lm-44. The crowns are plugged  into a motion labs distro 30a 240v. With the same exact setup and settings the mackie m1400 sounds much like Mr. Langston Holland describes the sound of the Camco vortex 6 for mid-hi's. I remember seeing a discussion on psw a while back about a similar issue brought to light about the crown 12000i in particular, but have been unable to locate it after much searching.

[Kashif Hudson]

Below is a quote from John Roberts in regard to a discussion started by Langston Holland about the I tech 8000 mid-hi behavior. If anyone is interested in reading further please use the search function and type "I tech 8000 mid-hi issue". I suspect the Ma12000i may be suffering a similar ailment. It looks like the 9k & 5k will perform better much like the I tech 6k & 4k did for mid-hi!

******If the loss is in the output filter as it appears, I'd expect the loss to be both gain and power. Applying corrective EQ boost would cause the amplifier to clip before raising the final output to full power.

This mechanism is pretty much limited to the very highest frequencies which in a natural distribution of musical energy will   be lower level providing the headroom needed to allow such a correction to work, that said it is far from ideal and this amp would need to be de-rated for use in the HF section of a multi-amped system.

Note: For some electronic music sources and close miked applications the natural distribution of musical energy may not be as reliably shaped as simple acoustic music so YMMV.*****

[Jim McKeveny]

Community RS880s have a passive network and limiting built-in. Power handling is only rated at 400w.  I would look for issues here rather than on fresh amps...

[David Sturzenbecher]

Below is a quote from John Roberts in regard to a discussion started by Langston Holland about the I tech 8000 mid-hi behavior. If anyone is interested in reading further please use the search function and type "I tech 8000 mid-hi issue". I suspect the Ma12000i may be suffering a similar ailment. It looks like the 9k & 5k will perform better much like the I tech 6k & 4k did for mid-hi!

******If the loss is in the output filter as it appears, I'd expect the loss to be both gain and power. Applying corrective EQ boost would cause the amplifier to clip before raising the final output to full power.

This mechanism is pretty much limited to the very highest frequencies which in a natural distribution of musical energy will   be lower level providing the headroom needed to allow such a correction to work, that said it is far from ideal and this amp would need to be de-rated for use in the HF section of a multi-amped system.

Note: For some electronic music sources and close miked applications the natural distribution of musical energy may not be as reliably shaped as simple acoustic music so YMMV.*****

I use Crown iTechHD 12000's (same amplifier section as the Macrotech 12000i) on the HF section of JBL Vertec quite often.  I have never heard, nor had any of the numerous A list engineers comment on any HF irregularities.

[Kashif Hudson]

David,

Here is a link to the amp review done by Langston Holland http://forums.prosoundweb.com/index.php?topic=132359.0
I think you will find this interesting especially if you had I techs previously. Langston also noticed that the sound greatly improved with HD models so no quarrels there.

[Kashif Hudson]

Jim,

Thanks for taking the time to contribute. 57v rms and 126v peak are easily converted and entered into the Crown and the Lake Lm. The 880s sound great at low levels and at higher levels. Infact, most would agree that the 12000i with the extra voltage capabilities should be superb at handling one 880 per side with plenty to spare. The problem is that in the higher frequencies the 12000i does not perform as well as it does in the lower bands. I noticed the problem that Langston did with the Itech 8k. John Roberts gave the technical explanation and theory for what is happening. Langston also made crown aware of the issue a long time ago. Please look at this discussion to help you understand further . These men are much more knowledgeable than I am. http://forums.prosoundweb.com/index.php?topic=81939.0

[ProSoundWeb Community]