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Signal Chain Loopback Measurements


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#21 Ricci

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Posted 19 March 2015 - 03:12 PM

Tons of loopbacks.

 

Note that on a few of the measurements you will see a sharp drop off or spike up near 20kHz. Those are artifacts due to the limitations of the measurements sampling rate and not part of the devices response.

 

EQ Devices:

 
Rane PE-17
rane pe17 fr.jpg
 
Symmetrix 551E
symetrix 551e fr.jpg
 
Behringer DCX2496
dcx2496 roll off 032612.jpg
 
 
Soundcards:
 
Turtle Beach SRM
srm 061510.jpg
 
M-Audio Mobile Pre
maudio mobilepre fr 052410.jpg
 
Presonus Firebox
firebox fr.jpg

 

 

Mixers:

 

Peavey PV-14

peavey pv14.jpg
 
Behringer Xenyx 1202
xenyx 1202 fr.jpg
 
 
Receivers / Processors:
 
Pioneer VSX-517K SW Out
vsx517k sw fr 200hz.jpg
 
Outlaw Audio Model 950 SW Out
outlaw 950 sw 150hz fr.jpg
 
Onkyo TX-SR806 SW Out
806 lf roll off.jpg

 

 

Amplifiers:

 

Crown CE4000

ce4000 fr.jpg
 
Crest Audio 8002
8002 ch 1.jpg
 
AETechron 7560 / Crown M600 (DC coupled)
7560 fr.jpg
 
QSC PL9.0PFC
pl9.0 fr.jpg
 
Powersoft K10 / Klein Hummel KPA-2400
k10 lf roll off.jpg

Attached Thumbnails

  • dcx2496 roll off 032612.jpg
  • 806 lf roll off.jpg
  • 7560 fr.jpg
  • 8002 ch 1.jpg
  • ce4000 fr.jpg
  • firebox fr.jpg
  • k10 lf roll off.jpg
  • maudio mobilepre fr 052410.jpg
  • outlaw 950 sw 150hz fr.jpg
  • xenyx 1202 fr.jpg
  • vsx517k sw fr 200hz.jpg
  • symetrix 551e fr.jpg
  • srm 061510.jpg
  • rane pe17 fr.jpg
  • pl9.0 fr.jpg
  • peavey pv14.jpg

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#22 Shredhead

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Posted 19 March 2015 - 03:29 PM

 

Tons of loopbacks

 

What is your interface/soundcard of choice these days?



#23 Ricci

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Posted 19 March 2015 - 07:52 PM

I still use a Presonus Firebox for most. I have 3. They are about -1dB at 8Hz and -2dB at 5Hz. Small, reliable and built like a tank. I have tried to find something else that perhaps measures a little bit flatter even than that but run into problems with headroom in the mic preamps with everything else I try.

 

The Firebox allows SPL calibrated measurements of right about 140dB using Earthworks M30 or M50 mics before clipping the preamp with the input trim bottomed out and a bit higher than that if I use the ACO rig, but to be honest after doing direct comparisons of the ACO rig versus the EW mics the only differences I could spot worth even mentioning were below 5Hz and they did not amount to much at all. Very close. I usually use an EW because it is a bit quicker and easier to setup due to less cables and one less ac plug. Most of the other interfaces including others from Presonus, M-Audio, Tascam and RME that I've tried just don't accept signals that hot and will clip when the levels reach 120-130dB. For most this wouldn't be an issue but I need the headroom and would have to switch to different mics or add an attenuator to get headroom in the measurement chain. Little bit different priorities for me than most other guys.

 

I'm still hoping to find something a bit better but I have been lazy lately.



#24 Shredhead

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Posted 19 March 2015 - 08:16 PM

I like Presonus, they seem to have good preamp sections.  I never got good sound out of M-audio's stuff for the price.  RME seems to be the new hot interface these days but I haven't messed with any of it. 

 

That's a boatload of loopthrus, thanks for posting.



#25 Madaeel

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Posted 19 March 2015 - 09:01 PM

My rear subs are about 6 feet away from the mic. The fronts are 14 feet away. The mic rolls off below 10hz without correction files. It is a UMIK from minidsp. I think I need to turn up the Adcom to get a better representation. My nearfield subs are not within 1 meter so room gain is kicking in but not quite as much as the front. All I did was turn the gain all the way down on each channel. Channel one runs the front array and channel 2 runs the back. The front array is 2 ohms and 8 drivers and the back is 4 ohms with 4 drivers.

Well this is the loopback thread so I think this should be in your own separate thread anyway, but that's exactly my point. Regardless of the rolloff the FR for both sets of subs in your graph are nearly identical. How can subs 6ft away have almost the *exact* same FR as subs 14ft away?? I guess anything is possible but that's highly unlikely. They're almost the same level and shape...

 

Sorry for the off-topic guys.



#26 MKtheater

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Posted 19 March 2015 - 09:43 PM

I was looking for a place to post. If they are wrong than the mic is bad.

#27 MemX

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Posted 19 March 2015 - 11:17 PM

That AETechron 7560 looks like a beast!



#28 Ricci

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Posted 20 March 2015 - 02:59 PM

That AETechron 7560 looks like a beast!

 

 

Oh they were. NO low frequency roll off on those. They were supposed to be good up to 70kHz or something like that as well. I kind of regret selling the pair I had. But they were 5 rack spaces tall and 100lbs each and really needed a dedicated 20A line to each. Would've been great for mains or an IB system.

 

I do have a few more loopbacks I can dig up and post I just have to figure out where I put those measurements.



#29 Madaeel

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Posted 20 March 2015 - 10:45 PM

Holy hell! That is one big amp. Though once you get them into postion you typically don't ever move them again...unless it's a Sherbourn. :angry:

 

That has got to be the best response so far. It actually has a hump at 5hz. Beautiful.



#30 LTD02

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Posted 21 March 2015 - 05:35 AM

road trip: https://sfbay.craigs...4932551093.html



#31 Ricci

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Posted 23 March 2015 - 01:27 AM

That's a great deal...if I remember right they will do 1 ohm as well.

Note the scale on that graph. Not much of a bump. Probably a measurement artifact.

#32 MemX

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Posted 31 March 2015 - 03:37 PM

Ok, so just pondering the possibilities of those crazy AETechron amps as a replacement for a (user-friendly) CV5000, wherein I'd need two (one to run each sub box at 2ohm) to replace the CV5000's stereo channels.

 

To ask what I'm quite sure will be stupid questions...

 

 

- I assume that with no ability to vary the gain (attenuation) in the amp itself (it looks like only the 7562 has an input attenuation knob) all gain modulation would need to be done by something before it in the chain?  (MiniDSP?)

 

- If so, how does one determine the suitable input voltage into the amp that will allow it to maximise output but with no clipping on the inputs?  (Would a Balanced MiniDSP's 2V output be enough power?)

 

- Was your amp expensive to repair when it broke?  (mentioned here: http://www.hometheat...rvice-dept.html before you sold it here: http://www.hometheat...anded-pair.html!)

 

- Are the fans noisy?  They look it!

 

- The PDF says that it has 'internal selection' of voltages (120v / 240v etc) (http://www.aetechron.com/pdf/7570.pdf) - does that mean it's automatic and doesn't have to be opened up?

 

 

Apologies for the annoying questions :ph34r:



#33 Ricci

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Posted 01 April 2015 - 02:42 PM

Yes it would be expensive to repair. Shipping 100lb amps is not cheap. Fans are loud yes. Input sensitivity specs should be listed at AeTechron along with schematics, etc.



#34 MemX

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Posted 01 April 2015 - 06:47 PM

Yes it would be expensive to repair. Shipping 100lb amps is not cheap. Fans are loud yes. Input sensitivity specs should be listed at AeTechron along with schematics, etc.

Thanks Ricci :)

 

I'll have to get my technical head on and read the spec sheets properly this time lol

 

Am considering taking a punt on getting one shipped over to the UK but it's not a cheap exercise if it is a broken unit!



#35 lukeamdman

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Posted 27 February 2016 - 11:54 PM

Here's a couple amp frequency response comparisons I took today.  The CC5500 is always the red line:

 

CC5500 vs SP2-12K:

 

CCvsSP2_zpsu6em3j3p.jpg

 

 

 

CC5500 vs. XLS 2500:

 

CCvsXLS_zpsyitboogz.jpg

 

 

 

CC5500 vs. NU4-6000:

 

CCvsNU4-6K_zpszsps8psa.jpg

 

 

 

CC5500 vs. LG IPD 2400:

 

CCvsIPD2400_zpsg2y51lyj.jpg



#36 NWCgrad

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Posted 28 February 2016 - 01:27 AM

The Crown did pretty well considering its reported 20 Hz HPF. It looks okay down to 10 Hz, I doubt anyone expected better results. Thanks Luke....
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#37 shadyJ

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Posted 28 February 2016 - 02:29 AM

Here are a couple computer sound interfaces if anyone cares:

 

MOTU UltraLite mk3 Hybrid:

MOTU_feedback.jpg

 

Behringer U-Phoria UM2:

Uphoria_feedack.jpg

 

Not bad for a $30 USB sound interface!



#38 lukeamdman

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Posted 28 May 2016 - 10:46 PM

Peavey CS 4080HZ (red) vs. Crest CC4000 (blue)

 

4080hzvscc4000_zpshojv2nuv.jpg



#39 lukeamdman

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Posted 26 August 2016 - 11:28 PM

Motu Ultralite AVB.  Line out to mic in:

 

 

Motu_zpsmfhk2w4y.jpg



#40 maxmercy

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Posted 28 August 2016 - 07:43 PM

-2dB at 2Hz is pretty darn good.

 

JSS






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