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Discussion Starter #142
No diagrams really, and a pic of the rat's nest (back of the rack) isn't really going to help either as it's a bit of a mess. Not like some people's I have seen, but not clean like Auburn's setup... I need to do a spring cleaning back there sometime in the near future, that's for sure.

My marantz has XLR out with two sub outs so I have both sub outs going to my miniDSP open DRC-AN for EQ. From there, sub "1" leaves the mini and I have Y-splitter to carry the signal to two different amp channels. sub "2" leaves and goes straight to its only sub channel on a different amp. Once you get further along, and have the equipment in hand, it gets much easier to visualize :D Keeping the amps close to the AVR makes it easier to run the interconnects. and keeps the lines shorter.
Agreed on this. My old 8801 (Pre) was hotter than the 7702 (pre) gets. I have always kept a 4RU space above my AVR/Pre to allow for proper ventilation. I know others who have bought the little USB fans they have connected to the back of their AVR to pull the heat from inside the unit and expel it, or have the fans tossing a crossbreeze over the top of their units. Either way likely helps.
Thanks for the explanation.... I didn't realize you could use a splitter.... makes sense as it is pre amp
4U over the AVR/Pre.... that's a lot of space...... more than I was thinking
Do you have a build thread.... looked for one but didn't see it


Big ole class A/B amps will produce a TON of heat. the more efficient class D/H/whatever class don't produce near as much.
Thanks


AVR at the very top???? It would be high and I am "vertically challenged"...... maybe fans would be better for me.....
 

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Discussion Starter #144
Cool thanks, so how do you like the Marantz?
Given all my gear is ancient, there are a lot of tough decisions and reviews coming.....
 

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The 7702 is fantastic. I am basically a tried and true D&M guy though. Onkyos tend to have more HDMI boards frying, and get hot enough to cook an egg on top, the yamaha offerings just tend to miss the boat a little on GUI and available tech, and really, I have found through owning at least half a dozen different denon and marantz units, they have all performed quite admirably. I did have one lemon that was just issue after issue. It is still sitting broken in my closet. I might sell it off to someone looking for a PRE, as the amplification circuit is all that is wrong with it actually.
 

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Discussion Starter #146
Thanks Beast, I was thinking Onkyo or Denon.... I guess I assumed Marantz would be out f my price range but in looking at them, I guessed wrong.


So, I see the 7702 is a preamp unit...... what decides if a person needs a "typical" AVR vs a pre amp unit?


I am guessing the following:
  1. Power of AVR is less that what is needed to drive speakers
  2. Number of speakers exceeds the AVR connections (e.g. running >2 subs)
 

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Thanks Beast, I was thinking Onkyo or Denon.... I guess I assumed Marantz would be out f my price range but in looking at them, I guessed wrong.


So, I see the 7702 is a preamp unit...... what decides if a person needs a "typical" AVR vs a pre amp unit?


I am guessing the following:
  1. Power of AVR is less that what is needed to drive speakers
  2. Number of speakers exceeds the AVR connections (e.g. running >2 subs)
Yea those are two good reasons :D I went the PRE route as I like to give my speakers substantially more power, while no receivers I am aware of can you run all surrounds channels as well as atmos without some sort of outboard amp. The rest of your design and listening levels will dictate what you need honestly.
 

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Sometimes you can alleviate some load from an AVR by removing some channels. This has an effect of more power and headroom on the channels you use it for.

It's common for an AVR to make more power in 2 channel than all channels driven, most of the time it's the power supply being limited. If you use an external amp you might want to use it as an upgrade for your front stage, rather than add an amp for ATMOS or extra surrounds. Use the AVR for only surrounds and use the amp for the fronts. The side effect is the AVR should have plenty of juice to drive only surround speakers, which often are crossed or have less dynamic/loud/low bass content that is troublesome on power delivery.

Just a thought ....
 

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Discussion Starter #150
So, I am having a tough time finding some local 12awg wire and shipping out of the US and our Canadian dollar is going to kill me in price.
According to the link below I should be ok with 14awg @80ft with an 8ohm load
Mackie C200's (500W peak) and Volt 6's (300W) are 8ohm

14awg is easy to get locally but I want to be sure I will be ok and not regret it in the future

My question is for the sub that would be 75ft of cable away..... what is a typical ohm rating on these?
Am I stressing over nothing.....

http://www.roger-russell.com/wire/wire.htm#wiretable



Another googled chart that says something different (from belden)


Yet another one with totally different info (mycablemart.com)





Thanks
 

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Discussion Starter #151

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yeah 12 gauge should shore up any concerns for most distances --- but a 75 foot run is pretty darn long --- what impedance is your subwoofer setup going to be using?


This should put your mind at ease somewhat. The Crown XLS-5000 is noted to be a beast of an amp and actually put forth a great deal more power than forum favorites like the Behringer EP4000. Even the Crown manual says you should be fine with 16 gauge wire up to 25foot. For 75' it should be 10 gauge minimum according to Crown.
http://www.avsforum.com/forum/155-diy-speakers-subs/1391011-when-running-2k-watts-subwoofer-what-gauge-speaker-wire-should-used-3.html#post21595273


2.5 Choose Output Wire and Connectors
Crown recommends using pre-built or professionally
wired, high-quality, two-conductor, heavy gauge
speaker wire and connectors. You may use 2-pole or 4-
pole Speakon® connectors (Figure 2.5 ), banana plugs,
or bare wire for your output connectors (Figure 2.6). To
prevent the possibility of short-circuits, wrap or otherwise
insulate exposed loudspeaker cable connectors.

Using the guidelines below, select the appropriate size
of wire based on the distance from amplifier to speaker.
CAUTION: Never use shielded cable for output
wiring.
Distance Wire Size
up to 25 ft. 16 AWG
25-40 ft. 14 AWG
41-60 ft. 12 AWG
61-100 ft. 10 AWG
101-150 ft. 8 AWG
151-250 ft. 6 AWG



-------------------------


There is more knowledge in that thread than I can impart.
FWIW - I actually used 12 gauge for my subwoofer runs just to be safe but none of my runs are over about 25 foot.
14 gauge is fine (read overkill) for your 8 ohm mains


Also ------ don't forget you can double up your speaker wire and it effectively is the same as 3 gauges larger. So doubling up two strands of 14 gauge speaker wire becomes 11 gauge - if that's a cheaper route for you. (four runs of 14gauge wire would be the equivalent of 8 gauge).
Man, 75 foot is a LONG distance, You should consider running your subs at 8ohm instead of 4ohm or 2ohm if you have the ability to ease the cable concern.
 

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Discussion Starter #158
why does it need to be local?
double check monoprice, but with the conversion right now, these guys tend to be a bit cheaper when all is said and done : http://www.cablesonsale.ca/index.php/audio-cables/monoprice-cl2-rated-in-wall-speaker-wire.html?gauge=21
Never heard of cablesonsale, thanks


500ft 12/2
Cablesonsale = $228.95CAD +S (? emailed to see)
Monoprice = $171.08USD * 1.31 = $224.41CAD +S (~103.29 based on14awg 12 is out of stock) = $327.70CAD
Part Express = $187.43USD.........
Blue Jeans (Beldin 5000UE) = 0.51/ft = $255USD *1.31 = 334.50CAD +S

Oh and don't forget duty and tax on the US shipped stuff.... add another ~$40 .... ugh

When I see the price basically double due to shipping and exchange I cringe..... thus the local search


14awg no problem and at an ok price locally


I have an electrician buddy looking into a couple belden number with the wholesalers..... we'll see....

yeah 12 gauge should shore up any concerns for most distances --- but a 75 foot run is pretty darn long --- what impedance is your subwoofer setup going to be using?.
This is one of the problems.... I don't know yet...... Looks like I might be forced to 8ohm...... but I hate pigeon holing my self and taking away options. How about you pick one for me :D

This should put your mind at ease somewhat. The Crown XLS-5000 is noted to be a beast of an amp and actually put forth a great deal more power than forum favorites like the Behringer EP4000. Even the Crown manual says you should be fine with 16 gauge wire up to 25foot. For 75' it should be 10 gauge minimum according to Crown.
http://www.avsforum.com/forum/155-diy-speakers-subs/1391011-when-running-2k-watts-subwoofer-what-gauge-speaker-wire-should-used-3.html#post21595273

2.5 Choose Output Wire and Connectors
Crown recommends using pre-built or professionally
wired, high-quality, two-conductor, heavy gauge
speaker wire and connectors. You may use 2-pole or 4-
pole Speakon® connectors (Figure 2.5 ), banana plugs,
or bare wire for your output connectors (Figure 2.6). To
prevent the possibility of short-circuits, wrap or otherwise
insulate exposed loudspeaker cable connectors.

Using the guidelines below, select the appropriate size
of wire based on the distance from amplifier to speaker.
CAUTION: Never use shielded cable for output
wiring.
Distance Wire Size
up to 25 ft. 16 AWG
25-40 ft. 14 AWG
41-60 ft. 12 AWG
61-100 ft. 10 AWG
101-150 ft. 8 AWG
151-250 ft. 6 AWG

-------------------------

There is more knowledge in that thread than I can impart..
Ya I read that whole thread this afternoon.... lot to take in. Some interesting point about peak / sustained and normal.
That bad boy does [email protected]/channel?.... Don't understand the whole 5000W in bridged.....:eek:


FWIW - I actually used 12 gauge for my subwoofer runs just to be safe but none of my runs are over about 25 foot..
Thanks
14 gauge is fine (read overkill) for your 8 ohm mains.
Cool that what I was reading..... you can say I told you so @beastaudio :eek:

Also ------ don't forget you can double up your speaker wire and it effectively is the same as 3 gauges larger. So doubling up two strands of 14 gauge speaker wire becomes 11 gauge - if that's a cheaper route for you. (four runs of 14gauge wire would be the equivalent of 8 gauge).
Man, 75 foot is a LONG distance, You should consider running your subs at 8ohm instead of 4ohm or 2ohm if you have the ability to ease the cable concern.
Ya I am looking into the cost that I would have to add to double 14awg vs just pay the USD for some 12awg


What are the pros/cons to running in 8ohm vs 2 vs 4?

You might want to use the 4 leads and wire them together.

You can buy 4 lead speaker wire pretty easy.
Ya been thinking about this also.......
 

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pros and cons to 8 ohm vs 4 ohm vs 2 ohm?

Virtually nothing in home theater application use in relation to sound quality.
It's more practical than that --- higher ohm load is easier on the amp, but requires more powerful amp to get the same power output levels, and allows for thinner cables without introducing audible distortion (at a given length). By contrast, a lower ohm load is more strain on the amp, but produces more output, and requires thicker copper cables. :) (super generic explanation)

More details:


2 ohm stereo is the same as 4 ohm bridged in regards to the amp's load.
4 ohm stereo is the same power output as 8 ohm bridged.


Generally this is the way amp power scaling works......

So e.g. - the Cerwin Vega CV-5000 puts out
2500 watts x 2 channels at 2ohm stereo (and 5,000 watts at 4 ohm bridged)
or 1800watt x 2 channels at 4 ohm stereo (and 3,600 watts at 8 ohm bridged)
or 1,100 watts x 2 channels at 8 ohm stereo (and likely (but unadvertised) 2,400 watts at 16 ohm bridged)
etc etc etc....


The CV-5000 is capable of running less than 2 ohm stereo, but it is limited by the power supply from producing much more than what it is rated for a 2 ohm stereo. That's typical of some of the nicer amps (speakerpower, etc) - they can run lower impedance than rated for - but they can't really produce any more power because the power supply is already 'mostly' maxed out at their 2 ohm rating. For instance. I run my CV-5000 at ~ 3ohm bridged right now on three nearfield UM18-22 subs wired to 1 ohm each. (they have dual 2ohm voice coils)



The historical guidance is running at 2ohm stereo is harder on the amplifier and is to be avoided in pro applications (that old adage is generally only applicable for pro audio DJ use where you are running an amp at max tilt for entire evenings --- some DJ professionals would tell you the only reason you should ever run an amp at two ohms is because one of your 4 or 8 ohm loaded amplifiers died and you are doubling down speakers at the lower impedance on the surviving amplifier to get you through the show at the same volume.) Running an amp at 2 ohm stereo creates more heat, and can stress the power supply more heavily. That said, LOT and LOTS of us AV enthusiasts run 2 ohm stereo in our home theater environments without any issue. Myself included when I had the 2ohm Captivators. I ran those successfully on a EP4000, an iNuke DSP 3000, and a Crown XLS-5000 at 2 ohm without issue. (well I did blow up a EP4000 - but that was fan modded and run for all she was worth at 2 ohm until she let out the magic smoke shortly after maxing her out. I think if I hadn't fan modded that unit it'd still be fine, cause my next new EP4000 never had any problems at 2ohm :) )

There is some dampening factors to contend with based on ohm load and cable distances but some people who understand much more about audio than me say dampening is pretty much completely negligible to our human ears in any given home theater setup - even if it can be measured with scientific tools. So you can probably pretty safely disregard anything related to dampening factor. The concern is pushed more heavily in audiophile circles.


You have a couple options. You can place your amps close to your subwoofers, and run a long XLR cable to provide signal - but that might introduce hum/noise into the signal line which is then amplified and annoying. Otherwise at those distances you probably ought to shoot for a 4 ohm load or 8 ohm load with the subs, run a long speaker wire, and just plan on buying more powerful amplifiers to account for your 4 or 8 ohm subs. It really isn't that big of a difference when you boil it all out.


Remember that a doubling of power is effectively only 3dB louder. So if you gave a sub 1,000 watts vs. 2,000 watts - the sub will only be 3dB louder with the extra power. That's basically three ticks on your AVR volume dial ---- say -13 to -10 main volume. Not that big of a deal at the end of the day. Quadrouple the power gets you ~six dB.




This might be time for another call so I can explain all the details out more easily. You still have my number?


No matter what your ohm rating on your subwoofer driver you can effectively reach many other common ohm configurations by using multiples of that driver. See some of these calcs to learn how that works...
http://www.the12volt.com/caraudio/woofer_configurations.asp
http://www.rockfordfosgate.com/rftech/woofer_wizard_form.asp
http://www.crutchfield.com/S-jdjsah9pOJ2/learn/learningcenter/car/subwoofers_wiring.html
http://www.bcae1.com/spkrmlti.htm
 

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Discussion Starter #160
THANKS A LOT @Archaea, I do still have your number and will reach out soon........ will need to read your post a couple of more times (twice already) :eek:to digest some of this and dumby up before I call.
 
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