Did you perform the "sub crawl" test to find your current sub location? Do you have REW setup so that you can take measurements? Your MLP could be in a null. Do you know what input voltage your amp needs to have in order to output 500w?
-
Get an exclusive sneak peek into our new project. >>> Click Here
-
Our native mobile app has a new name: Fora Communities. Learn more.
Sub amp connected to receiver but vol is low
So after having the amp and sub for a few years I finally had time to build an enclosure for it and got it connected last night for the first time. Anticipation was high but unfortunately the volume was not.
My setup
- Receiver - Denon 1905
- Sub amp - QSC RMX850
- Sub - SI HT18D4
- Amp connected to receiver direct though RCA using a 1/4” phono to RCA adapter
- Speaker is bridged at amp with voice coils running in series so should have 8 ohm load. Amp is rated around 500 watts at 8 ohm bridged
- Dip switches on back of amp are set for parallel inputs and bridged output. All filters and clipping is off
- Receiver is set to have sub as LFE+Main
- amp gains turned 3/4-max and receiver set to +12db
So I get sound (bass) out of the sub. But it’s almost non existent. I’m expecting this thing to “almost” rattle my house to the ground but I’m pretty sure I’d have more output from a 5” driver running free air. My old Def Tech 10” sub is slaughtering this thing. So I know I have something wrong.
I don’t have a mini dsp as of yet, not any other doodads. Is it possible that the sub output voltage is too low for the amp to adequately amplify? I have a small behringer mixer that I could use in between the amp and receiver for testing if that would help.
Thoughts and thanks.
Sent from my iPhone using Tapatalk
My setup
- Receiver - Denon 1905
- Sub amp - QSC RMX850
- Sub - SI HT18D4
- Amp connected to receiver direct though RCA using a 1/4” phono to RCA adapter
- Speaker is bridged at amp with voice coils running in series so should have 8 ohm load. Amp is rated around 500 watts at 8 ohm bridged
- Dip switches on back of amp are set for parallel inputs and bridged output. All filters and clipping is off
- Receiver is set to have sub as LFE+Main
- amp gains turned 3/4-max and receiver set to +12db
So I get sound (bass) out of the sub. But it’s almost non existent. I’m expecting this thing to “almost” rattle my house to the ground but I’m pretty sure I’d have more output from a 5” driver running free air. My old Def Tech 10” sub is slaughtering this thing. So I know I have something wrong.
I don’t have a mini dsp as of yet, not any other doodads. Is it possible that the sub output voltage is too low for the amp to adequately amplify? I have a small behringer mixer that I could use in between the amp and receiver for testing if that would help.
Thoughts and thanks.
Sent from my iPhone using Tapatalk
1 - 20 of 24 Posts
I looked up the manual online. The dip switches should be set for bridge mode, not parallel mode. Use input and gain for channel 1.
Input sensitivity is 1.15v on that amp, shouldn’t be a problem. I assume your old sub was working with those receiver settings?
My father runs a pair of HT18’s on 600w audiosource amps and they work well.
Chris
Input sensitivity is 1.15v on that amp, shouldn’t be a problem. I assume your old sub was working with those receiver settings?
My father runs a pair of HT18’s on 600w audiosource amps and they work well.
Chris
Attachments
-
131.3 KB Views: 25 -
146 KB Views: 20
Is your 1/4" adapter a TS or a TRS? This one bit me. Make sure it's TS.
Joseph
Joseph
How have you wired the speakOn plug? The amp end should be wired to 1+ and 2+.
Where do you have the filter set?
^ see above. Take a picture or post a link of the 1/4" adapter being used.
Where do you have the filter set?
^ see above. Take a picture or post a link of the 1/4" adapter being used.
I looked up the manual online. The dip switches should be set for bridge mode, not parallel mode. Use input and gain for channel 1.
Input sensitivity is 1.15v on that amp, shouldn’t be a problem. I assume your old sub was working with those receiver settings?
My father runs a pair of HT18’s on 600w audiosource amps and they work well.
Chris
I think you’re mistaken or maybe I am, my understanding is that you have to put the dip switches in parallel mode so that the L and R inputs are combined as a single input. Do you disagree? At any rate, I can give it a shot changing it and report back.
Sent from my iPhone using Tapatalk
Is your 1/4" adapter a TS or a TRS? This one bit me. Make sure it's TS.
Joseph
Great question I’m not sure. Will look at it tonight when I get home.
Sent from my iPhone using Tapatalk
How have you wired the speakOn plug? The amp end should be wired to 1+ and 2+.
Where do you have the filter set?
^ see above. Take a picture or post a link of the 1/4" adapter being used.
Didn’t use the speakon outputs. Used the binding posts.
Will look at the 1/4 plug though.
Sent from my iPhone using Tapatalk
I posted a pic of the manual in my first post, but here is a comparison showing both options.I looked up the manual online. The dip switches should be set for bridge mode, not parallel mode. Use input and gain for channel 1.
Input sensitivity is 1.15v on that amp, shouldn’️t be a problem. I assume your old sub was working with those receiver settings?
My father runs a pair of HT18’️s on 600w audiosource amps and they work well.
Chris
I think you’️re mistaken or maybe I am, my understanding is that you have to put the dip switches in parallel mode so that the L and R inputs are combined as a single input. Do you disagree? At any rate, I can give it a shot changing it and report back.
Sent from my iPhone using Tapatalk
I also suspect the 1/4 adapter. Is it a single rca to TS? A TRS plug will work, if its internally shorted, but most adapters won’t be.
Chris
Attachments
-
191.9 KB Views: 13
Ahh, gotcha. Should be good to go with that setting.Sorry should’️ve looked and explained better. In the bridged pic you can see dips 4,5,6,7 al in the right position. 4 and 5 in the right position is for parallel inputs. If they were in the left position the inputs would be in stereo.
Sent from my iPhone using Tapatalk
Whelp that looks to be the culprit. It’s definitely a TS plug and not a TRS. Before I order a plug am I better off using an adapter or buy a conversion cable? If a conversion cable should I do rca to xlr? Or does it really not matter?
Sent from my iPhone using Tapatalk
Sent from my iPhone using Tapatalk
Really doesn't matter, you're going from unbalanced to balanced either way. I've had good luck with Monoprice's RCA -> XLR cables: https://www.amazon.com/Monoprice-XLR-Male-RCA-Cable/dp/B001VLW398Whelp that looks to be the culprit. It’s definitely a TS plug and not a TRS. Before I order a plug am I better off using an adapter or buy a conversion cable? If a conversion cable should I do rca to xlr? Or does it really not matter?
Whelp that looks to be the culprit. It’s definitely a TS plug and not a TRS. Before I order a plug am I better off using an adapter or buy a conversion cable? If a conversion cable should I do rca to xlr? Or does it really not matter?
Sent from my iPhone using Tapatalk
Actually, a TS plug should be working fine. It just shorts the (-) and (ground), which is correct for unbalanced input.
Have you tried another subwoofer on the avr to confirm its output is working?
Chris
Sent from my iPhone using Tapatalk
Yeah I had my old def tech running before.
Sent from my iPhone using Tapatalk
Sent from my iPhone using Tapatalk
The instructions on the back clearly state to use CH 1 inputs only for Bridge Mode. Why do you have two inputs?I think you’re mistaken or maybe I am, my understanding is that you have to put the dip switches in parallel mode so that the L and R inputs are combined as a single input. Do you disagree? At any rate, I can give it a shot changing it and report back.
Sent from my iPhone using Tapatalk
TS is what you want. two metal sections with one black divider. TRS has 3 metal sections with two black dividers.Whelp that looks to be the culprit. It’s definitely a TS plug and not a TRS. Before I order a plug am I better off using an adapter or buy a conversion cable? If a conversion cable should I do rca to xlr? Or does it really not matter?
Sent from my iPhone using Tapatalk
Hmm never mind then. I have the right type then. I’ll do some more troubleshooting tonight, maybe try a different adapter.
Sent from my iPhone using Tapatalk
Sent from my iPhone using Tapatalk
Do you have a multimeter? If so, check the resistance at the amplifier terminals to verify correct wiring.
Do you have a different speaker to try on the amplifier? Doesn’t need to be a sub.
Do you have a different amp to try?
Chris
Sent from my iPhone using Tapatalk
Do you have a different speaker to try on the amplifier? Doesn’t need to be a sub.
Do you have a different amp to try?
Chris
Sent from my iPhone using Tapatalk
1 - 20 of 24 Posts
- This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
AVS Forum
A forum community dedicated to home theater owners and enthusiasts. Come join the discussion about home audio/video, TVs, projectors, screens, receivers, speakers, projects, DIY’s, product reviews, accessories, classifieds, and more!
Full Forum Listing
Top Contributors this Month
View All
WilliamR
940 Replies
BASSAHOLIC
514 Replies
bass addict
401 Replies
Recommended Communities
