# On Display or In the AV Closet Cabling Considerations



## sawyer (Feb 10, 2013)

Display your gear with minimal cable lengths or separate your gear in a closet and live with much longer cable lengths? These are two different approaches folks take and a lot of ad-hoc in between. The approach I have taken is to provision two a/v closets supporting three home theater deployments with a goal of extending to bath and kitchen for whole home a/v - keeping the gear and cabling out of sight and also envisioning transitions of floor standing speakers to in-wall in select cases over time. Additionally having room EQ, measurement microphones, audio analyzer for quality control deployed and capturing all the time.
Considerations of assessing noise/gain/interconnects of equipment such as discussed in this forum's sticky "audio, equipment, explained:, gain, home, structure, system, theater Sticky Thread Gain Structure for Home Theater: Getting the Most from Pro Audio Equipment in Your System" provides a gainstructureprocedure.pdf for assessment.

The caution with the a/v closet approach is 
1) Regardless of perceived "benefits" adding gear and wiring into an analog signal chain will result in loss/degradation. The question is - is the loss acceptable and manageable and are the benefits worth it?
2) cable lengths can be many times longer than the "display your gear" approach so proceed with the knowledge that the a/v closet approach as defined here is sub-optimal when compared with the "display your gear approach"



I just bought a Samson active crossover and a behringer deq2496 audio analyzer/REQ/Equalizer, emm-6, will be adding REW and minidsp at some point. This all to start in part to assess how much folly I have created by choosing the "hide the gear" in the a/v closet approach. I note that even in the best "display your gear" approach folks find in adding gear the noise spec of the gear is basically incompatible when a poor choice is made adding gear that becomes the lowest common denominator of the chain.

In closet cable lengths are minimal 3 feet between shelves with a/v receiver to amp 6' cables then introducing gear between a/v receiver and amp 6 feet cables each.

When connecting to external components. I have one run to rear subwoofers that is 20' as the crow flies but the actual cable run is 100'. I just obtained 150' microphone xlr cable to pre-deploy the EQ microphone at this location and have extra length for repositioning the measure to all interesting locations.

The A/V closets have been re-worked a number of times - this approach actually encourages rework as the cabling is hidden from view. If you have torn down your setup and rebuilt you know that "dressing cables" is an art with multiple criteria of goodness.
In all fairness though this is an analog concern expressed here but the criteria for moving in this direction was driven by digital as a very significant amount of this capability of the av closet is off topic iin hdmi multiplexers, splitters, and cat6 extenders.

So this thread to document where some of the limits of this "hide the gear" approach are or techniques to manage.


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## ajinfla (May 10, 2009)

Hi Sawyer.

You've lost me a bit here. What _specific_ "losses" are you concerned with? The 100' rear sub cable is indeed pretty long. What type of cable and what are you driving it with? The Samson?
Why do you need a 150' mic cable? Is it permanent?
Thanks


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## sawyer (Feb 10, 2013)

AJ-- Thanks for your reply.
Quick answer is there are three different wiring runs deployed with at the worst case cable length 100'-150' and multiple uses for each wiring type - ie speaker;12awg; sub 16awg; xlr mic 16awg; 

The intent is to place the xlr microphone on the 150' length for about 1 year to allow for ongoing assessment of the environment. The challenge/balance of course is keeping the residence clean for it's occupants and functional. For example I have a 100' run of 16awg cable deployed for rear speakers awaiting replacement with an unopened roll of 12awg cable sitting on the floor next to me while I type this - so prioritizing and and understanding how this approach dictates temporary and permanent compromises is important. Because the behringer will be taking it's calbrated input from the mic i would expect a shorter length for that step would be prudent whereas the longer length may be nice to have to see the frequency display and ultimately available to correlate with some next steps using another to be implemented mic with REW (and minidsp)

I certainly had reservations purchasing 150' 16awg xlr mic cable for obvious reasons. I probably will get another 30' length to pull out and use for spot checks when i have the residence to myself. Again that would be my assumption without performing the specific calculation. Another assumption is that the 150' is not going to be totally useless. I am totally fine with folks expressing an opinion and/or supporting with calculation implying that the calculated difference is "x db" and likely significant or insignificant.


I see here
http://www.electrovoice.com/cableloss.php
an online calculator to use the awg and length to obtain a portion of the calculated measures.


There are a number of specific losses that concern me that accompany the "In the Closet" approach to deploying. Each of which deserve specific calculation, confirmation by direction measurement, and compensation by electronic processing. 


I am putting forward that this approach inherently increases many connection lengths and even in the a/v closet where lengths could be optimal the choice to support rapid reconfiguration can make lengths longer there as well.
The worst case "rear" destination of this deployment is the focus here at which point where until a through the ceiling low voltage conduit is implemented the run requires 100' run length and which up to 150' length of cable has been used for some connections in the interim.

Note: all cabling obtained from monoprice; identifying cable specs as available and required.
The specific losses in this case for:
1) SPEAKERS- 100' length of 4 conductor in-wall for two speakers 16awg down to be replaced with 12awg; for rear surround speakers also used as "all channel stereo speakers"
2) PWRD SUBWOOFER- 100' length 16AWG copper conductors and a copper braid shield,RCA CL2 Rated Cable - RG6/U 75ohm
for pair of rear subwoofers; Pre-out from Integra dtr-7.8 A/V receiver split 5x for four subs and input to transducer amplifier.
3)EQ/ MICROPHONE-150' xlr microphone cable 16AWG copper conductors; copper braid shield, 97.5% coverage for electromagnetic and/or radio frequency interference


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## Wayne A. Pflughaupt (Apr 13, 2006)

The only real problem related to long audio signal runs is _loss_ – which merely means a reduction in signal strength. In the unlikely event that it’s enough to be a problem, it can easily be addressed with the relevant gain controls – that’s what they’re for. For the cable lengths and wire gauges you’re talking about, it’s essentially a non-issue.

Regards, 
Wayne


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## sawyer (Feb 10, 2013)

In a word, "great!". 
With all the issues encountered with placing gear out of sight in an A/V closet and having increased lengths result for analog audio connections, it's good to know analog cable length is not in itself a problem that doesn't have a ready solution.


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## wd3 (Feb 23, 2014)

Another issue with using a distribution closet would be heat. You need to make sure the closet is well ventilated (read: perhaps it has its own air return) to keep the equipment from over heating.


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## Tonto (Jun 30, 2007)

Agreed, I had an AC duct run into my equipment closet just foor cooling & a return placed in the theater room itself.


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## sawyer (Feb 10, 2013)

I agree - A/V Closet needs a forced air return to vent the heat. Unfortunately, I am not there yet.
My short term solution- 
14 ENERMAX ENLOBAL Bearing Fans from Monoprice - these are the magnetic-barometric design to run friction-free and noiseless. 8 fans on top of 4 Hafler amps, 4 fans on top of 2 Integra A/V Receivers and two fans to vent. With the door open I have reduced the closet environment temp of the Haflers to 97 degrees. As the fans are pulling from inside each case I estimate that the component temps are not dramatically higher. I think that is the best case spin on the current situation. These fans quiet and can be readily be cleaned as I understand dust buildup rapidly will produce wobble and noise in any 120mm size fans. Next step put a thermocouple inside the case to determine what the temp is. 

As an interim solution all 14 fans are driven by one ac transformer with the power wiring branching out in all directions and lightweight fans tip over readily - so dressing these cables is an issue and securing the fan placement and but only after suitable solution is determined. Those inexpensive powerful Haflers are not seeming so inexpensive any more.


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