Go dual Subwoofers!

IWC Dopplel

Distinguished Member
Hi I run 3 sonus Faber Cremona subs that are aligned and level adjusted (not actually volume matched) and EQ’d across the seating area these are not ported but have two passive 12” drivers. The way I did this was to effectively match the levels of all subs for volume then look at the time alignment in theory and then with REW and I ended up with small differences between them (the delta will mean that say 4,4,6 will be the same and 5,5,7) then you move the ‘group’ to align with the Fronts/centre. Then I spent quite a bit of time looking at each sub and how they combine at the different seating position, then made some more individual tweaks to the EQ and volume of each sub at each seat to get the compromise to be the most efficient and further improve the curve.

I then added the 18 and looked at the alignment and SPL so I could blend the 18 in with the others. I looked at 20,25,30 Hz as the choice to align with the group of 3 and I had a dip at 25Hz, removed by adding a bit more delay of the 18. I also looked at where I should roll off the 18

Initially the curve looked great and 8ms was the best for the 18 in terms of technical combination, I then spent some time listening and preferred less delay, it was tighter and more coherent with less smearing, I settled on 1.5ms. It measured worse though with a small dip at 25Hz at 1.5ms

Listening to two channel I spent some time with the three SF subs and ended up moving from 3,3,5 to 3.4,3.4,5.5 after extensive listening and adding the 18 I moved much further and now this runs 1.3 ms, now I criticise myself here to question a fraction of a ms, really !? But I believe I can here this 0.2ms with a-b with the 18. Not life changing just marginally better I think.

Regarding rolling off I settled on the 18 going to 41 Hz(-6db) so really rolling of from mid 30’s, the 12” subs are flat to 70Hz then roll off. If I roll the 18 later then I need to bring down the volume of each of the three subs as they are all providing output from 17Hz, the 18 from 5Hz

I did a few EQs and recorded the figures to add more of the 18 and less from the 12’s so I could a-b with different settings and decided on the 41 Hz point and the blend with a few more db from the 18 and a few less from the 3 x 12's

All the speakers have the subs picking up the lower frequencies that are missed by the speakers running full range, I use a 10x10 mini dsp for this, just to do the bass

So really 5-17Hz is the 18, 17-25Hz is all 4subs, 25-35 all mains,surrounds and 4 subs, 35-70 all mains and surround and 3 12” subs, 70Hz+ just mains and surrounds

My L,C,R,SL,SR,are good in the 30-40 range, the rears are strong above 40, so I prefer to run all the 7 channels full range and just add what is missing (possible with the 10x10, as you have EQ on the input and output) I run parallel leads so the main channels are not corrupted by EQ and additional A>D D>A it’s just the low frequencies I align and EQ
 
Last edited:

IWC Dopplel

Distinguished Member
By the way I tried rolling in the 12’s at say 20 as they struggle below there really, I had horrible timing issues and it sounded wrong. I have heard some say rolling off is easier to align than rolling on and off

All of my subs are open at the lower frequencies and roll off only. I only add BEQ to the 18 (BEQ Catalogue) and only add 50% of the recommended lift,
 

AndreNewman

Active Member
Hi I run 3 sonus Faber Cremona subs that are aligned and level adjusted
Sounds a bit like Dirac Unison, all drivers full range working together but achieved the hard way.

Interesting.
 

JustinT350

Active Member
For dual subs, is a miniDSP always required, even if the AVR has dual subwoofer outputs and its own subwoofer EQ HT?

About Audyssey Sub EQ HT™​

Audyssey Sub EQ HT™ makes the integration of dual subwoofers seamless by first compensating for any level and delay differences between the two subwoofers and then applying Audyssey MultEQ® XT32 to both subwoofers together.
 

Mr Wolf

Well-known Member
Not "required" as such but it should give you the ability to get a smoother in-room frequency response and the ability to add a House Curve. Its level of benefit to you also depends on the subs - if they have built in manual PEQ filters then you could get get a measurement mic and tweak Audyssey's result manually to fine tune the FR (or do it in reverse and get Audyssey to polish off the FR that you've already tweaked with the PEQs). That may be enough for you - this method got my FR to within a 9dB window. A few months later I bought a MiniDSP which got it to within a 3dB window.

Personally, as a minimum I would buy a UMIK-1 microphone so you can at least accurately measure what Audyssey has done for you and go from there. You'll be needing one if you end up going the MiniDSP route anyway. It actually has many uses.
 

JustinT350

Active Member
Thanks Mr Wolf.

I've got a UMIK 1 already, and the sub is the SVS pro with the app for minor tweaks. Your post just helps justify me moving to duals! :D

I wonder if there will be any black friday deals coming...
 

Conrad

Moderator
@IWC Dopplel’s set up is… uncommon, to say the least!

Get duals, get an UMIK, probably get a minidsp 2x4HD. Take measurements, head over to the REW thread and post your file.

Job done!
 

Conrad

Moderator
That kit costs nearly as much as the sub does lol.

If your AVR manages dual subs then you can get away without them. Still worth getting later as they can make a big difference to a set-up
 

Mr Wolf

Well-known Member
IMO a UMIK-1 is worth buying in its own right as it would help optimise various other things and could be used to take (post-Audyssey EQ) measurements that would help you determine the extent to which a MiniDSP 2X4HD would be beneficial to you. That's the 2-stage route I took and the measurements first showed me dual subs were essential and later that a MiniDSP was essential if I wanted an even bass response.
 

Mr Wolf

Well-known Member
Are you sure Conrad? I thought the dual sub EQ feature only came with Audyssey XT32 which starts at X3xxx series upwards. I think the X2600's XT system doesn't set independent sub levels and distances for dual subs and its two sub RCA outputs is effectively the result of an internal y-splitter of one sub-out signal.
 

Conrad

Moderator
The question was: "when you say manage dual subs do you mean that it can set volume and distance etc independent of each other?"

My answer was yes, thats what I meant. Apologies if that wasn't clear.

Can the 2600 do that, I have no idea, doesn't sound like it.
 

Broadsword

Well-known Member

Thanks, I need to check but I think that only starts from the x3 models and higher.

The question was: "when you say manage dual subs do you mean that it can set volume and distance etc independent of each other?"

My answer was yes, thats what I meant. Apologies if that wasn't clear.

Can the 2600 do that, I have no idea, doesn't sound like it.

I understood what you meant. Think it starts at the 3 series and above.

Is it possible that adding a second sub with the amp I have would result in a worsening of what I have already. I have 2 or 3 sub locations it could go in but no more really. Without having to buy additional kit?
 

Toobad

Active Member
@IWC Dopplel’s set up is… uncommon, to say the least!

That's the beauty of our hobby, you have the freedom to explore the technology to a level you are comfortable with. If you are still using the Denon X2600, I don't think it can handle 2 subwoofers independently so your options are to upgrade to the X3xxx series and above or invest in a miniDSP/UMIK.

Remember, if Jessica Alba knocked on the door demanding you make love to her there and then, there are some people who would only agree provided they could do it standing up in a hammock! :D
 

Conrad

Moderator
Thanks, I need to check but I think that only starts from the x3 models and higher.



I understood what you meant. Think it starts at the 3 series and above.

Is it possible that adding a second sub with the amp I have would result in a worsening of what I have already. I have 2 or 3 sub locations it could go in but no more really. Without having to buy additional kit?

Yes, you could make things worse. The chances of plonking the sub down and it being ideal are slim.

To @Mr Wolf’s point, an umik is a very useful purchase without a minidsp and you can get some of the way with measurements, REW, and a phase control on the sub.
 

Dobbyisfree

Well-known Member
Just as a point to all so that they don't purchase an AVR or AVP used assuming... Audyssey Sub EQ HT is the name of the system where two subwoofers are setup individually. It mostly (90% of the market) comes with Audyssey XT32 - but not always. Some Onkyos for example have XT32 but not Sub EQ HT.

For Denons, as has been said, as far as I'm aware it's only ever been offered on 3 series and above. And that isn't on all of them. For example, for the 3 series, I think it was the x3300 onwards.

The ZKelectronics site does have a separate line item for Sub EQ HT.

Regarding how good it is? Well, it's limited and offers no where near as much tweakability as a MiniDSP. But it is a lot simpler. Care needs to be taken afterwards to limit down the top EQ frequency in the Audyssey app, this makes a massive difference to what it can do... particularly with subs (like mine) that mentally go right up the frequency range (they output up to ~1kHz).

As far as I know, many antimodes again are not as tweakable as MiniDSP.

Also, so you're aware, the new Audyssey laptop control system is soon to be launched. AVF members report that this could go back to all Denons that have the app control. So, at this time, many people are sitting on the fence about upgrades/purchases to wait and see what this can do. For example, with Sub EQ HT, there may be a lot more configuration options. A good example at the moment, with the app, is that it doesn't even show you results for each sub separately!
 

diverdog

Active Member
Take a look at Todd Welti's AES paper or Harman info on this subject. In rectangular rooms with two subs midpoints on front and back or side walls work best. He shows results for different seating locations and room sizes. My 17' x18' 5" x 10' room will have 4 subs located in the corners.
REW unequalized predicted response for multiple seats is amazing!
 

Attachments

  • Bass Sim 4 Corners crop.png
    Bass Sim 4 Corners crop.png
    84.9 KB · Views: 25

The latest video from AVForums

Sony Bravia XR A80J OLED TV Review
Subscribe to our YouTube channel

Latest News

What's new on Sky and NOW UK for February 2022
  • By Andy Bassett
  • Published
Piega launches Ace Wireless speakers
  • By Andy Bassett
  • Published
M&K Sound launches V+ Series subwoofers
  • By Andy Bassett
  • Published
Denon launches DHT-S517 Dolby Atmos soundbar
  • By Andy Bassett
  • Published
Perlisten Audio launches loudspeaker ranges in UK
  • By Andy Bassett
  • Published

Full fat HDMI teeshirts

Support AVForums with Patreon

Top Bottom