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Can an unused amplifier pair of Denon AVR-X3700H AVR be used to feed passive subwoofers? (Yes)

Chromatischism

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I don’t think there's any way to get the avr to do proper bass eq/management/crossover etc. without using the sub outs.
This was my thought as well, but he is using the sub outputs for signal.
 
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sarumbear

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Then @voodooless posted a Hornresp showing like 105 dB for 1W-that is a hell of a lot more (closed perfect shoebox room?). I gotta wonder if there is really that much gain in a real room. And given that much room gain, do two subs really give another 6 dB? From some theoretical idea yes but I've never seen it tested that I recall.
I think that is question to the software author that @woodooless used

Any possibility to measure the actual response of these subwoofers? My interest is very piqued. Ideally each separately and then together.
I’m afraid I have converted my friends room to a lab enough times already. I am not going to it again. Sorry.

I'd also be curious your comments why you chose that driver over a more "pro" driver (not disagreeing, mind you, just wondering what factors were considered)
It is a pro driver. It’s sold by the JBL’s Pro division! There’s even a 1.1 kilowatt version of the driver. Check the link above.
 

Chromatischism

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Wait, what? If I put in 91.5 dB sensitivity, 2W, 3m, in corner, I get 91 dB. Not 100 dB. Did I do something wrong?

Then @voodooless posted a Hornresp showing like 105 dB for 1W-that is a hell of a lot more (closed perfect shoebox room?). I gotta wonder if there is really that much gain in a real room. And given that much room gain, do two subs really give another 6 dB? From some theoretical idea yes but I've never seen it tested that I recall.

Any possibility to measure the actual response of these subwoofers? My interest is very piqued. Ideally each separately and then together. I'd also be curious your comments why you chose that driver over a more "pro" driver (not disagreeing, mind you, just wondering what factors were considered)
Just going by the numbers, it wouldn't seem my 2x15" vented with 900w RMS each should be capable of 125 dB peaks at 30 Hz, but they are according to RTA in my room.
 

Head_Unit

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Just going by the numbers, it wouldn't seem my 2x15" vented with 900w RMS each should be capable of 125 dB peaks at 30 Hz, but they are according to RTA in my room.
No, that's not a surprise to me at all. 900W≈30 dBW. Back out from 125 = 95 dB for 1 watt. With two subs I assume big and tuned low, and if the room is well sealed, seems possible. The 100 dB from 2 watts now from a "91 dB" driver, that seems weird. II guess if the room is sealed and there is that much gain maybe it's not so weird.
 

Head_Unit

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I’m afraid I have converted my friends room to a lab enough times already. I am not going to it again. Sorry.
It is a pro driver. It’s sold by the JBL’s Pro division! There’s even a 1.1 kilowatt version of the driver. Check the link above.
What I meant by "Pro" was one of the like "99 dB" kind of things. I'll look at the link again, maybe they have shifted their designs since those halcyon days, realizing those high midband sensitivities have little or nothing to do with low bass sensitivity (that's an area I want to do some more modeling in).
 
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sarumbear

sarumbear

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What I meant by "Pro" was one of the like "99 dB" kind of things. I'll look at the link again, maybe they have shifted their designs since those halcyon days, realizing those high midband sensitivities have little or nothing to do with low bass sensitivity (that's an area I want to do some more modeling in).
I use drivers from this range as the high sensitivity range has too powerful magnets. They are not suitable for extension to sub frequencies and/or require too large an enclosure with EQ, which would negate the high sensitivity advantage.

 
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BDWoody

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Could the X3700H technically drive passive subs, yes. If you hooked them up to the Height 2 binding posts, then looped the subwoofer RCA output into one of the analogue inputs such as CD, and selected that as your Zone 2 playback source.

Please read this post as well, which gave clear instruction on how to do it, and furthermore, I set it up as described and it is working!

Ok, I must be doing something wrong.

Figured I'd give it a try to see if I could put away my amp.

Hooked up as described, but when I went to use the setup process, it did not send anything out through the zone 2/sub amp. It (Z2) was non-responsive to input until I exited the setup menu. It's hard to believe the zone 2 would be left on during setup and calibration, but it has clearly worked for you, so I'm wondering what I'm missing.

Is there a trick you had to employ, or did it just work?
 
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sarumbear

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Ok, I must be doing something wrong.

Figured I'd give it a try to see if I could put away my amp.

Hooked up as described, but when I went to use the setup process, it did not send anything out through the zone 2/sub amp. It (Z2) was non-responsive to input until I exited the setup menu. It's hard to believe the zone 2 would be left on during setup and calibration, but it has clearly worked for you, so I'm wondering what I'm missing.

Is there a trick you had to employ, or did it just work?
I have not done anything special. I'm sure you have done these but just to be sure:
  • Have you tried to see if your selected input is working, i.e. amplifying the input signal?
  • I patched Sub outputs to CD inputs as by default CD was assigned as input 5. I then selected input 5 for Zone 2 using the remote.
 
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