Question Denon Receiver advice

swanny78

Active Member
Good afternoon fellow AV fans. A quick question and advice needed please. I have a dedicated cinema room (converted single garage). Its carpeted but has brick walls with some acoustic treatment on reflection points etc. I think its about 2.5m by 6m ish. I have an ATMOS set up in a 5.1.2 configuration typical positioning of speakers as recommended by Dolby. I have recently purchased some new speakers Q Acoustics concept 40's and a new sub Q acoustics QB12 sub. My Receiver is a Denon AVR-2600.
Now the 2600 seems fine in powering the speakers as they have a nominal impedance of 8ohms so fairly easy to drive. My concern seems to be when I start to get close to reference levels the sub seems to what I can only explain as make a muffled wobble sound and sounds rough. I am pretty sure from googling the issue it's being clipped by the amp. I have had to drop the db on the sub from the measured +6db to about 1.5db to prevent that happening. I don't use high volumes that often but I like to use it now and again. Before I buy a 2nd sub should I also be looking for a better amp to power the subs. The Q12 are pretty high spec as assume should manage the load the 2600 is putting on them, hence I think its the amp clipping the signal. I was looking at the next Denon up the AVR-3700. This seems to be a big step up in capability , although must admit I wont use a lot of the advanced video features as I use a Epson 9200 projector which can not do things like 8K, HLG, HDR @60Hz etc and does pixel shift to get a pseudo 4k image. I am pleased with the image tho.
So to my question is the upgrade to the 3700 something I should do, or am I wasting a grand on something I won't get benefit from, if the latter how do I sort the annoying subwoofer clipping?

Any advice welcome and thank you in advance.
 

mfp2gosling1

Active Member
I have all of my speakers, except for my 2 subs, running through a power amp, it takes away any concerns of clipping.
 

swanny78

Active Member
I have all of my speakers, except for my 2 subs, running through a power amp, it takes away any concerns of clipping.
Its the sub that I think is clipping, is that possible on a powered Sub with integrated amp? I'd assumed my receiver is just sending the signal to the sub with no amplification. If I bought a 2 channel power amp to reduce the load on the receiver would that help the subs? Would be a cheaper option.
 

Gasp3621

Distinguished Member
@swanny78

You don´t need to change the av-receiver. Sounds like you are trying to run it too much boosted and you are asking too much from the QA sub which is more of lounge sub to keep wife happy. Not sure why you bought QA sub for dedicated room in first place. There is no need to "match" speakers and subs.

You talked about +6db figure, what is this? Subwoofer trim or subwoofer level under Denon menu? Clearly it can´t take it if you run it 6db hotter after calibration with reference volume!

If you go to subwoofer level in the menu assuming you haven´t touched it, what was it set to when you ran Audussey?
 

gibbsy

Moderator
It does sound like the sub is the problem here. Bundled subs are never that great and you may benefit from getting a third party sub from dedicated builders such as BK or REL. If you have +6dB after calibration using Audyssey then that level, although well within the control parameters set by Audyssey, it may just causing the sub to bottom out on bass heavy scenes depending on your overall global level.
 

swanny78

Active Member
Cheers @gibbsy and @Gasp3621 . The QB12 Sub was not bundled with the speakers, I bought it separately from the Q Acoustics Concept 40 speakers, these are the Q Acoustic flagship speakers. It is the upgraded SUB too so its the best they do. So while there are bigger\better subs out there the QB12 is no slouch and would think it can cope, hence I thought it was the amp, but now I'm not sure ;-). Sub specs below.

I think you are both right, I think ill review audessy settings and look at sub positioning. probable will get another sub too.
  • Peak Amplifier Power: 440 W
  • Continuous Amplifier Power: 220 W
  • Power type: Class D
  • Frequency range: 28 Hz - 300 Hz
  • Crossover frequency range: 40Hz – 250Hz
 

gibbsy

Moderator
Plenty of power available from the sub. Always somewhat difficult to get the placing of subs right and do you think you have been getting boundary issues at a certain frequency? You could try the crawl test. Place the sub on your listening position chair, play a music track that has a repetitive bass note. Crawl on your hands and knees and find the position in the room where the bass sounds nice and tight. Put the sub there and re-run Audyssey.

This is always best done with the curtains of the room closed as your neighbours might think that lockdown has got to you.:)
 

swanny78

Active Member
Plenty of power available from the sub. Always somewhat difficult to get the placing of subs right and do you think you have been getting boundary issues at a certain frequency? You could try the crawl test. Place the sub on your listening position chair, play a music track that has a repetitive bass note. Crawl on your hands and knees and find the position in the room where the bass sounds nice and tight. Put the sub there and re-run Audyssey.

This is always best done with the curtains of the room closed as your neighbours might think that lockdown has got to you.:)
Cheers Gibbsy, yes Its in the corner next to and inside of the left speaker, I think this might be part of the problem and means gain on amp needs to be ramped up on the LFE channel. Think Ill need a longer sub \ RCA cable ;-). Will a second sub help?
 

gibbsy

Moderator
Cheers Gibbsy, yes Its in the corner next to and inside of the left speaker, I think this might be part of the problem and means gain on amp needs to be ramped up on the LFE channel. Think Ill need a longer sub \ RCA cable ;-). Will a second sub help?
Two subs will more often than not, improve the bass in the room as it will help cut out on nulls and give a more even bass response. Just like speakers it is pretty important to have those subs matching. I've got a small REL sub and they are designed to work in a corner and I'm very lucky in it's actual positioning but even then it was small adjustments in the actual position that yielded the best results.

There's no way I could get a bigger sub past the wife let alone a second one. A frying pan in the face often offends and probably hurts.:lesson:
 

Gasp3621

Distinguished Member
Cheers @gibbsy and @Gasp3621 . The QB12 Sub was not bundled with the speakers, I bought it separately from the Q Acoustics Concept 40 speakers, these are the Q Acoustic flagship speakers. It is the upgraded SUB too so its the best they do. So while there are bigger\better subs out there the QB12 is no slouch and would think it can cope, hence I thought it was the amp, but now I'm not sure ;-). Sub specs below.

I think you are both right, I think ill review audessy settings and look at sub positioning. probable will get another sub too.
  • Peak Amplifier Power: 440 W
  • Continuous Amplifier Power: 220 W
  • Power type: Class D
  • Frequency range: 28 Hz - 300 Hz
  • Crossover frequency range: 40Hz – 250Hz

2nd identical sub can help, but 500£ for that sub wouldn`t be best way to spend money cause there is better models for little more. You will get more headroom with 2nd QB12, but they won´t dig any deeper. 28hz as low point in FR, not a product for dedicated HT room.

Small room, small sealed sub i would try the sub at front corner to get the most performance out of it due to boundary gain. Run Audussey again if you move it with the volume knob around 12clock, phase knob at 0, crossover knob at max (=AV), power switch at On over Auto.

After running Audussey check subwoofer level that it´s below -12db. Let`s say -10 to -6db would be ideal so you can tweak this figure safely at the negative trim side. And if you listen reference volume you can´t run it as hot as you did. But let`s see how the corner loading affects as you get "free output" by moving it there.
 

swanny78

Active Member
2nd identical sub can help, but 500£ for that sub wouldn`t be best way to spend money cause there is better models for little more. You will get more headroom with 2nd QB12, but they won´t dig any deeper. 28hz as low point in FR, not a product for dedicated HT room.

Small room, small sealed sub i would try the sub at front corner to get the most performance out of it due to boundary gain. Run Audussey again if you move it with the volume knob around 12clock, phase knob at 0, crossover knob at max (=AV), power switch at On over Auto.

After running Audussey check subwoofer level that it´s below -12db. Let`s say -10 to -6db would be ideal so you can tweak this figure safely at the negative trim side. And if you listen reference volume you can´t run it as hot as you did. But let`s see how the corner loading affects as you get "free output" by moving it there.
Great thanks , I’ll give that a go over weekend and report back .
 

swanny78

Active Member
Couldn't seem to trim the sub to an appropriate level, to fill the room was bottoming out at +3db on receiver anything lower had very little impactful bass. So gave up with current setup. I bought a second sub (another QB12 Sub) and an upgraded Amp with independent sub controls (Denon AVR 3700). This also comes with Audessy 32XT. I have to say the change is night and day. The receiver sub trim level is set to -5.5 db on both rather than +3 or +6. The bass is immense now and really ahs made a huge difference - ,more than happy now, but £1500 lighter
 

Gasp3621

Distinguished Member
Couldn't seem to trim the sub to an appropriate level, to fill the room was bottoming out at +3db on receiver anything lower had very little impactful bass. So gave up with current setup. I bought a second sub (another QB12 Sub) and an upgraded Amp with independent sub controls (Denon AVR 3700). This also comes with Audessy 32XT. I have to say the change is night and day. The receiver sub trim level is set to -5.5 db on both rather than +3 or +6. The bass is immense now and really ahs made a huge difference - ,more than happy now, but £1500 lighter

Happy to hear it worked out. Keep in mind that you might get better results with the subs located bit differently than as what looks best (two at front close each other). You can download REW program and use the Room Simulation, you can then move the subs there and listener too, this will give you idea the response you get. You will just add your room dimensions for it. Here is some basics, check the pictures at midway forward. It still doesn´t mean X way would work best in your room. Either you would measure the response or use the free program!

The -5,5db on both subs is very much ideal. Now you have still headroom to run them hotter if you feel so. So moving from -5,5db on both to -2,5db for example. What is enough is up to you. Just don´t touch the subs physical knows, do the changes from Denon menu (subwoofer level).


 

swanny78

Active Member
Happy to hear it worked out. Keep in mind that you might get better results with the subs located bit differently than as what looks best (two at front close each other). You can download REW program and use the Room Simulation, you can then move the subs there and listener too, this will give you idea the response you get. You will just add your room dimensions for it. Here is some basics, check the pictures at midway forward. It still doesn´t mean X way would work best in your room. Either you would measure the response or use the free program!

The -5,5db on both subs is very much ideal. Now you have still headroom to run them hotter if you feel so. So moving from -5,5db on both to -2,5db for example. What is enough is up to you. Just don´t touch the subs physical knows, do the changes from Denon menu (subwoofer level).


great thank you Gasp3621, good advice will take a look
 

JustinT350

Active Member
I've also just taken delivery of the 3700. Very impressed so far, audessey is superb for setting up the room

I need to spend sometime having a play with the settings as I'm struggling a bit with bass
 

gibbsy

Moderator
I need to spend sometime having a play with the settings as I'm struggling a bit with bass
The actual position of the sub can make a big difference in response. Try moving the sub around a little or indeed try the good old sub crawl. Place the sub on the seat that the Audyssey measurements are taken from in position 1. Play some music that has a repetitive bass line and crawl on your hands and knees until you have a good even bass response. Place the sub there and re-run Audyssey.
 

swanny78

Active Member
I did the good old bass crawl and my position I had it in was pretty good actually. Luck more than design. I watched a few videos on YouTube about using REW to set up multi subs with a miniDSP. Looks great however I would need to pay for new mic and miniDSP and probably nit worth the outlay for me at the moment as I am more than happy. REW has its advantage over bass crawl in that bass crawl only identifies the sweet spot I guess where as REW can improve bass response for everybody in a multi sub set up .
 

Gasp3621

Distinguished Member
I did the good old bass crawl and my position I had it in was pretty good actually. Luck more than design. I watched a few videos on YouTube about using REW to set up multi subs with a miniDSP. Looks great however I would need to pay for new mic and miniDSP and probably nit worth the outlay for me at the moment as I am more than happy. REW has its advantage over bass crawl in that bass crawl only identifies the sweet spot I guess where as REW can improve bass response for everybody in a multi sub set up .
I meant use the room simulation function in the REW program and add two subs in possible locations after you have added your room dimensions, see which offers the smoothest response. There is sub 1 and 2 which you select, enclosure put sealed and for the -3db you put 28hz. Also select time align subs and spekers plus align subs individually. If you have some dips/nulls (with 1 sub) you can play with the 2nd sub location to smooth it. Now you don´t get that information with subwoofer crawl. The program works if you have fairly normal square room. You can do this without the mic to find out which are the best spots to give you smoothest response without dips. I would want to see the diagonally opposite front/rear corners.

Subwoofer crawl is not good method. Why is that listen 7:46 about 5-10min forward. When you have time you should listen this whole video. Click play it starts in correct time:

 

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