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Old 4th March 2011, 05:53 PM   #511
jbell is offline jbell  United States
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Quote:
Originally Posted by Djim View Post
Oh yes Jbell! My fluke 45 measures TRUE RMS from 20Hz-20Khz and audio power calculations from 1.6 to 16.4 Ohm. But it only measures correct with a single sine wave signal. (It also measures dBs from 2 to 8000 Ohm impedances and frequencies from 5Hz-1Mhz).
Djim:

you have a very fine piece of test equipment that has the ac+dc function. I included the link since there had been discussion about 'true rms' in the recent past. I though it may be enlightening for some on how true rms meters work.

maybe some day I'll step up to a 'real' meter... till then, I suffer through with my 'poor mans fluke'
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Old 4th March 2011, 06:40 PM   #512
Djim is offline Djim  Netherlands
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Jbell, it’s not about the equipment because you can doubt any setting in this forum. It’s all about consistence in measurement methods and the knowledge behind these tools... (but sometimes a more expensive tool can be handy)
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Old 4th March 2011, 06:40 PM   #513
FlipC is offline FlipC  United States
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Ha
I could build my version of the TH221 for the cost of that Fluke meter!
I use a cheapo Asian DDM. HDM4100. probably like $30-40 bucks new.

It is going to be raining this weekend
so if I do get to test it will be inside. But I will be sure to do test and post.
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Old 7th March 2011, 06:01 AM   #514
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Quote:
Originally Posted by jbell View Post
DIY highpass for making things idiot proof? That's what xti amps are for....
Crown XTi-1000 Stereo Power Amp

Ben/Scott, I appreciate the thought, and I've even considered a 500uf passive or other type of active protection for my subs... but I just can't beat the simple setup of the xti.


$329 for full '3yr no fault' warranty b-stock... delay, dsp, eq, highpass, limiter, amp... all in a password protected, front panel lock out, 17lb all digital chassis.... Runs a pair of tops and a pair of subs beautifully. And limits out WAY before 900 watts per driver is possible. Using the internal 'Y' so that there is only a single audio input, and a single volume control even keeps peoples hands off of the sub/top volume ratio, so things always sound the way you want them to sound. To top it off -- 2 channel speakon cables even prevent mis-wiring on setup.... just chain all the speakers together.. Start on the side/top, go to the 2 center clustered subs, and then on over to the other side top.... beautiful.

I've been using nothing else for my school installs.... which have to be idiot proof....
This has me very curious/interested..
1. Are you running only 1 XTi amp for all 4 cabs/feeding each SS15 w/only 250W?
2. Does the XTi have a 'brick-wall' limiter?

I'm looking for my best option for installs and a lot of them are for clubs. I worry, even w/proper gain structure, that a novice DJ will get too happy w/the channel gain and get well into the red. I understand there may not be anything to prevent this other than giving proper instructions to each DJ.

How have you found the XTi amps to do with the lows? Find any drawbacks yet?

Regards,
Justin
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Old 7th March 2011, 12:30 PM   #515
jbell is offline jbell  United States
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Quote:
Originally Posted by CRESCENDO View Post
This has me very curious/interested..
1. Are you running only 1 XTi amp for all 4 cabs/feeding each SS15 w/only 250W?
2. Does the XTi have a 'brick-wall' limiter?
yes,and yes...

The xti1000 with the brick wall limiter engaged is monkey proof. The ONLY way a dj could disable or in any way defeat your settings would be to have access to the rear of the amp, have a usb cable and laptop running the bandmanager software and know your password.

For installs I like to limit at 1/2 PE of the drivers so I have 100% reliability no matter what, which is why the xti1000 fits exactly what I need. If you want a bit more bass for a DJ set up that is still monkey proof, run 3 ss15 cabinets, a pair of tops and step up to an xti2000.

As far as running subs with one channel of an xti -- I have had zero problems.
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Old 7th March 2011, 12:48 PM   #516
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Default Thanks! That's it!

I've been looking for a name for my weekend hire company.

"Monkey proof systems" would be perfect.
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Old 7th March 2011, 01:00 PM   #517
jbell is offline jbell  United States
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Originally Posted by salzburgsoundsystem View Post
I've been looking for a name for my weekend hire company.

"Monkey proof systems" would be perfect.
yea, that's it.... and it fits. not even a monkey could jack this up...

eq -- crossover -- limiter -- amp, in a single chassis. The entire gain structure is your mixer and the amp... that's it. The only thing that works on the front is the power switch and channel one volume knob. And the volume knob only goes to 10, not to 11.... Channel 2 knob doesn't even do anything when the 'internal y' input selection is made.

You can limit in 3db increments each individual channel, so your tops can have a different limit than the subs. I mean..... it's MONKEY PROOF !!
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Old 7th March 2011, 02:24 PM   #518
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Quote:
The over all path leght is about 97.875" long, but do you do the box resonance from S1 to S5 or S2 to S4 in a tapped horn.
Can anyone help me with this?
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Old 7th March 2011, 03:50 PM   #519
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I assume nominal 8ohm and test either at 2.83v@1m or 28.3 volt@10m.
Jim what signal are you using to set the 2.83 volts? IE can I set the gain of the amp to get 2.83 volts RMS using 60Hz and regular DVM and then do the SPL cheaks. Or do I have to readjust the gain of the amp for each frequency I test? I thought some said thare was a thred or a link for the testing setup and procedures?
Thanks Andy
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Old 7th March 2011, 08:47 PM   #520
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Quote:
Originally Posted by jbell View Post
yes,and yes...

The xti1000 with the brick wall limiter engaged is monkey proof. The ONLY way a dj could disable or in any way defeat your settings would be to have access to the rear of the amp, have a usb cable and laptop running the bandmanager software and know your password.

For installs I like to limit at 1/2 PE of the drivers so I have 100% reliability no matter what, which is why the xti1000 fits exactly what I need. If you want a bit more bass for a DJ set up that is still monkey proof, run 3 ss15 cabinets, a pair of tops and step up to an xti2000.

As far as running subs with one channel of an xti -- I have had zero problems.
Well, this answer is only....EXACTLY what I was looking for

So, with the system setup this way, will the drivers/amp not get damaged from under-powering and hitting the limiter constantly (IF the performer treats the mixer's output to do so)?

Using the SS15 as an example, how does this setup compare (other than dollars & cents) to a setup where the amp has 500W/63V to 1000W/89V rms available per driver with the brick wall limiter set to a few dB below 63V?

Last, but not least: I remember you speaking of going from the amp output to a top, that top to the subs and the subs to the other top. This is with using 12GA ext cord for speaker wire with speakons, right? Would you mind further explaining how this all works?

Regards,
Justin
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