Yeah, I figured as you initially said it was out of the question. Not sure what you could do to be honest, apart from trying to lower the signal level on one channel. But also that will probably not sound perfect in any way.
@Ian_Webster
Roon’s DSP convolution will largely ameliorate your troubles.
It only costs a hundred bucks for the calibrated microphone and the time to study and learn the process.
Check out:
A guide how to do room correction and use it in Roon
Highly recommended…
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Thank you Marin - I have two amps at home that I swap between. An ARCAM AVR850 for home theater and a Cambridge Audio 851N/851W for two channel. I just swap the speaker cables back and forth as needed. The ARCAM comes with DIRAC - but I haven’t set t up yet (only had the amp a couple of weeks.) If that helps on the home theater side then I’ll work on the room correction in ROON for two channel duties.
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One thing I did notice is that the Todd Welti and Allan Devantier study had the listeners in the middle of the room. So the time delays from all speakers would be similar. If the listeners were closer to the back wall, then the time delays from the rear subs would be different to the front ones, and maybe that could cause a perceivable change in quality.
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Some folks like the sound of bass, pulsing, thumping and booming, objects moving, walls and windows vibrating. I’m not one of those, but can make it happen if guests are so inclined. I found a BASS Test CD from a Roon search and playing it can really get things moving/vibrating.
But for me, when there is deep bass in music, drums, double bass, low organ notes, I like to hear and/or feel it.
Subs can extend the capabilities of the speakers with proper integration, without calling attention to there locations, the deep bass is there without being able to distinguish where it is coming from.
In our living/entertainment room the main seating area is in the center with 7 lower level speakers all around, one sub in the front right corner, one in the left rear corner, and 4 height speakers. With stereo the sound is obviously from the front wall where the towers are and the deep bass seems to be coming from there as well. With surround its predominantly from the front wall but the sound is all around you.
Nice to have options for what you want to hear.
2 channel subs should ideally be around where the left and right speakers are to give similar balance to the stereo image. HT is a whole different ball game
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The following is an excerpt from Don Saltzman’s review of the REL 212 subwoofers from the Absolute Sound (available on line).
The Bottom Line
In a word, the REL 212/SEs are sublime. Like a linebacker who loves to paint, they have the ability to hit hard when called for, but their more gentle side allows delicate brush strokes that infuse the midrange and upper frequencies with three-dimensional body and sheer presence. The degree to which the 212s improved the already excellent midrange and high frequencies of my system came as the biggest surprise. Their superb bass added a degree of air and space to the sound that, seemingly, only comes with quality reproduction of the low frequencies.
He used a pair of the REL’s with Maggie 20.7’s. He also goes into speaker placement provided by a REL employee/expert installer. It is very good reading.
Edit 1 I have a pair of JL Audio E112’s and it made a huge difference using them with my (nearly) full range McIntosh speakers. It completely changed the treble and midrange SQ for the better, the bass has wonderful tone and is controlled by my preamp adjustment from the listening position. I have my subs crossed over a 55-60hz even though the speakers extend to 30hz.
People struggle to identify where a sub-bass sound is coming from - our ears are not sufficiently capable of locating it. Also, most research says that in order to counter modes in a small room the ideal placement of subs is not aligned with the speakers.
See slide 75 here (or the entire presentation if you are interested): https://www.harman.com/documents/multsubs_0.pdf
I have my subs aligned with the speakers. For me it was more about room pressurization and countering room modes than volume.
Thanks, interesting presentation! Loved the Matlab simulations, especially this comment about the simulation of 5,000 subwoofers(!)
"Can a sufficiently large number of subwoofers cancel out all room modes?
Theoretically yes
Practically NO"
Mind you, I’m not sure where the listeners would be sitting, unles they were using very tiny subwoofers! Although I guess with 5,000 they could be quite small - the Baudline Piston Excursion calculator says 5,000 1 inch drivers would produce 110 db at 20 Hz with a 1.75 mm Xmax!)
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Thank you for this info. Planning to building some Subs this winter to add to my system (Devialet Pro220 with Magico S1 speakers). The plan is to build using Baltic Birch with Scan Speak 9.5 inch driver and Hypex amp.
Have copied your posts to my project file.
Thank you very much
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You’re very welcome Randy.
I haven’t been following this thread since my last post as I’ve been off doing other things, so I don’t know what all has been said since my last post.
Anyway, may I suggest something about your DIY subwoofer project?.. Depending on the capabilities of that Hypex amplifier and the impedance of that Scan Speak driver you’ll be using, maybe use two drivers and have them mounted in the enclosure on opposite sides, opposite each other, or one driver physically inverted (the basket and magnet “hanging” out of the enclosure) known as push-pull.
Take a look at the many current dual driver subwoofers of today and the old M&K push-pull subwoofers from back in the 80’s and 90’s.
Both designs greatly reduce enclosure vibrations, increase powering handling and increase output. The push-pull designs reduce even-order distortion between the two drivers since the cone and suspension of one driver is moving backwards into the enclosure while the cone and suspension of the other driver is moving forwards into the enclosure at the same time. They’re still acoustically in phase, but are electrically out of phase. It’s this opposite motion of the two drivers at the same time that cancels out the even-order distortions between the two drivers.
Theoretically, these two designs should also have a bit “quicker” and tighter bass as both drivers are equally sharing the work load, only having to do half the work to produce the same output. And doing half the work is also lowering the possible distortion by half as well.
Other than DIY open baffle subwoofer designs, these opposed and/or push-pull DIY designs always performed best in my experience. Over the years, I’ve built many of both designs with great success.
Anyway, just a thought.
I could tell from your text that you have an InoAudio setup! And yes, confirmed by your link. I also have i14 but with infra Y4. The things our non Swedish friends are missing…
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I have two JL F113s supporting the bottom end of my room. I used to have them inside my main speakers and was always frustrated with room modes. I tried various frequency filters and crossover points and I could not even the response out. Then, I moved one sub to the back of the room and the response magically (well, scientifically) evened out.
However, I never felt one sub was better than two. You can never understate how important the room is to the sub response.
Hello Charles. Thank you for your suggestions. I will keep all your suggestions in mind as a finalize my sub design. My original plan was to build sealed cabinets using Baltic Birch on edge with 1 1/4 inch walls for max stability (as was used some original Magico speaker designs).
I had looked at the multi/apposing driver idea but though it to complex an idea for an armature builder . With your suggestions I will research that idea further. A man in local Audio shop has been very helpful offering design suggestions and how to integrate subs in to the system (very similar to your suggestions). While this guy sells audio gear he also offers his own line of speaker largely based on Transmission Line designs. I did listen to his designs and some ported designs but found I preferred the sound of sealed speaker cabinets designs.
Guess I had assumed that would apply to subwoofer design as well!
Winter rains have arrived in these parts and what with lock down and all, it good time to new speaker project. This winter the plan is to build the subs, integrate them and then add in room correction.
Thank you again Charles / Randy
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You’re welcome Randy. Glad to share info and experiences with fellow audio dudes!
Sounds like we had the same frustrations. I tried all the crossover tweaks too. My dealer suggested the same idea about my room/sub interaction. They even offered to lend me a smaller sub to move around the room to try different locations to try. I may take them up on it to experiment once the snow and cold come.
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