Hey all,
It's been a long time since I've done speaker design. Back when all that existed was a giant spreadsheet to figure out baffle effect, etc. However, I've recently relocated to an apartment, and am investigating ways to create some bass response without annoying the neighbors (if this is even possible).
The units seem insulated pretty well, which is nice. The system setup here is pretty low-key. Some transmission line Dayton towers, and small Dayton surrounds.
To fill out the bass I'm curious if anyone has any thoughts on a small, 8" subwoofer placed directly behind the main viewing seat, potentially at head height, and potentially open baffle to reduce transference.
I doubt I'll be able to get the "feel" I would want, but am hoping to get at least a bit more low-end out of things.
Thoughts or ideas?
It's been a long time since I've done speaker design. Back when all that existed was a giant spreadsheet to figure out baffle effect, etc. However, I've recently relocated to an apartment, and am investigating ways to create some bass response without annoying the neighbors (if this is even possible).
The units seem insulated pretty well, which is nice. The system setup here is pretty low-key. Some transmission line Dayton towers, and small Dayton surrounds.
To fill out the bass I'm curious if anyone has any thoughts on a small, 8" subwoofer placed directly behind the main viewing seat, potentially at head height, and potentially open baffle to reduce transference.
I doubt I'll be able to get the "feel" I would want, but am hoping to get at least a bit more low-end out of things.
Thoughts or ideas?
I've done many nearfield OB experiments for exactly this application. In a couple of years I am downsizing into an apartment. I've been designing the audio system that I will take with me.
My experiments have shown some >20dB reduction in bass leakage when running a nearfield OB bass system. The bass levels that could be achieved at the listening seat while being almost inaudible on the other side of a 3mm pane of glass were quite amazing.
You may want to consider a driver bigger than 8" though. A pair of 12" drivers with modest excursion should give you all the bass you want without annoying the neighbors. I'd be tempted to go for dipole front speakers too. At the ~80Hz X/O the front TL's will be easy to hear through the structure.
My experiments have shown some >20dB reduction in bass leakage when running a nearfield OB bass system. The bass levels that could be achieved at the listening seat while being almost inaudible on the other side of a 3mm pane of glass were quite amazing.
You may want to consider a driver bigger than 8" though. A pair of 12" drivers with modest excursion should give you all the bass you want without annoying the neighbors. I'd be tempted to go for dipole front speakers too. At the ~80Hz X/O the front TL's will be easy to hear through the structure.
First off, thanks for responding, sounds like you are the perfect person to get some insight from!
Thanks again!
This is very heartening. Sounds like I may be able to pull this off.
How has driver size and paring factor in to your tests so far? I have an 83" wide couch, and a 71" wide table behind it. I will either be putting the surrounds to the side of the couch or if I must, on the edges of the rear table angled in (still figuring this out). I had planned for the single 8" sub to be mounted directly behind the primary seat at head level. At such a low volume, what would dual 12s give me, and what would you recommend for the layout? A single 8" sub I can hide in the decor, two 12s, not so much! I had also considered isolating the couch and adding a bass shaker, too.
Yea, I'll have to figure this one out, I already have the TLs (Dayton Audio MK442T 4" 2-Way Transmission Line Tower Speaker Pair).
Thanks again!
I'm not entirely sure I understand how this meets the needs of the request. I've got a 5.1 setup already in the works, and am looking to fill in with a NF subwoofer to fill things out. Is there something specific I'm missing?
Do you have experience with the 12" woofer in an open baffle that you could describe? Thanks!
Even in a near-field open-baffle design, I can't imagine two high excursion 15s wouldn't be rattling the neighbors. It looks like you've got that in a solid-floor setup, so do you think this still applies?
Perhaps I'm not grasping something about the physics of near-field or open-baffle. I do like how you have those behind the couch. I could pull something like that off with the table I have hiding them somewhat. What are the differences of having them directly facing the back of the couch vs at head level?
Thanks!
Another related question, what's better for this, high Qts or excursion?
Looking at some options, there are some very affordable high Qts drivers that get recommended for open baffle, for instance I could run multiple drivers of:
Qts/Xmax = .98/8.5mm - GRS 12SW-4 12" Poly Cone Subwoofer 4 Ohm
or
Qts/Xmax = 1.26/3.5mm - GRS 12PR-8 12" Poly Cone Rubber Surround Woofer
However, that's not a lot of excursion for a 12" woofer. I was also considering a single (at a much higher price point):
Qts/Xmax = .59/19mm - Dayton Audio UM12-22 12" Ultimax DVC Subwoofer 2 ohms Per Coil
Which has a much lower Qts but ridiculously large Xmax. Lastly, to keep things looking nice, an ideal solution if the numbers line up would be one of these due to the low profile:
Qts/Xmax = .51/10mm - Dayton Audio LS12-44 12" Low Profile Subwoofer Dual 4 Ohm
If I can place these facing the couch below head height, it would be ideal, but I don't know how much that will impact the near-field effect. Thoughts?
Looking at some options, there are some very affordable high Qts drivers that get recommended for open baffle, for instance I could run multiple drivers of:
Qts/Xmax = .98/8.5mm - GRS 12SW-4 12" Poly Cone Subwoofer 4 Ohm
or
Qts/Xmax = 1.26/3.5mm - GRS 12PR-8 12" Poly Cone Rubber Surround Woofer
However, that's not a lot of excursion for a 12" woofer. I was also considering a single (at a much higher price point):
Qts/Xmax = .59/19mm - Dayton Audio UM12-22 12" Ultimax DVC Subwoofer 2 ohms Per Coil
Which has a much lower Qts but ridiculously large Xmax. Lastly, to keep things looking nice, an ideal solution if the numbers line up would be one of these due to the low profile:
Qts/Xmax = .51/10mm - Dayton Audio LS12-44 12" Low Profile Subwoofer Dual 4 Ohm
If I can place these facing the couch below head height, it would be ideal, but I don't know how much that will impact the near-field effect. Thoughts?
LOL, I was going to suggest the OP check out the avsforum.com Tactical Response thread!
You still have the best looking BOSS platform!
The point of open baffle is more feel rather than spl. Because I was curious I ran downstairs and put some EDM bass music on at -5db MV which is about 111db at my MLP and then turned my mains and subs off, I set my mic up and let it play a couple of songs and ran around the house doing stuff while my kids were getting ready for bed.
91db is all hey could get to... that’s a 20db reduction and nobody in my house even noticed. There was some bleed off on some notes but mostly because of the shaking, not necessarily the spl.
I said high excursion because of my need to hit the lower notes <20hz and it does it way better than the JBLs I had in there once before. If normal <80hz the jbls were fine but adding the high excursion drivers really took the 5-10hz stuff to the next level while still doing up to 80hz.
Putting them at head level is pointless imho, you need to feel not hear which means move what you sit on or it will just be wasted.
Yes, I’m on concrete and yes there is a lot of movement so isolators under the couch will help relieve the neighbors of bass being transmitted to the floor / walls.
If I had an apartment I would try this route before the BOSS platform while still having isolators under the couch feet. I think the forward / back motion would create less problems than the up / down UNLESS I was on the bottom floor concrete floor.
Here is version 1 of my couch and a single chair. FYI - I hated the driver firing straight into my butt.
@fmstrat here is the list someone else made. This should help you, it helped me.
The Tactile Response Thread for BASS
) - Page 31 - AVS Forum | Home Theater Discussions And Reviews
The Tactile Response Thread for BASS
) - Page 31 - AVS Forum | Home Theater Discussions And ReviewsSorry, I think I read the response to you suggesting that you go "all dipole" and conflated the posts after a few beers. Also your OP implied that you might be designing new mains... anyway I do think you should consider a full-range dipole system. I also think you should consider no less than a 12" woofer per side if you want 40hz dipole low end at near field listening distances. Or a 12" nearfield dipole sub behind your head if you want it for HT. Every octave deeper you want to play as dipole needs 4x the cone displacement for the same SPL you would get from a monopole.
I've built a few dipole systems (one with 4x12" servo subs) and the quality of the bass really is special. The SPL is there to measure, but the dishes in your cupboard don't rattle because there is no room pressurization. In the upper-bass/low-midrange the cleanliness of room interaction is wonderful. If you go for a dipole near-field sub you may want to keep going for the whole frequency range.
When I think of near-field I think of speakers that can sacrifice some dynamic headroom for transient and pattern control. If I wanted to build a "quiet" but exquisite near-field system for an apartment I would build with the drivers I mentioned. But if that's off-topic I apologize!
Oh I've been a member there for years and years, and did query them related to equipment selection, but this forum seemed more suited to the specific use-case of a near-field open-baffle sub.
This was a straight-up fantastic read. Thank you! A couple of questions:
1) So are you recommending a dipole setup in near-field? And second to that, I can't actually tell if his design is a dipole open baffle because his picture is so close up. Any insight on this?
2) From the article:
I wish he had tested position G at head level. It seems he was in the dipole null because of the height difference, where had the sub been at head level he may have been in an anti-null, which is what I'm going for. That being said, his measurements at F and H make me feel good that I'm headed the right direction.
Neighbor friendly dipole sub
Opposed woofers cancel cabinet vibrations, so structural vibrations are not transferred to the floor.
Opposed woofers cancel cabinet vibrations, so structural vibrations are not transferred to the floor.
OB Nearfield Bass looks too interesting to let the thread die. Any updates?
I agree.
My experiments date back several years. I never measured the difference in leakage between a sealed box and a dipole at the same level. With hindsight I should have, but the difference was so dramatic I felt it was unnecessary. I was doing the experiments for my own interest and the conclusion I came to was nearfield OB bass was a no brainer for anyone who wants to control bass leakage in a medium or high density residential situation. My wife and I will be moving into a townhouse next year with an adjoining party wall to neighbours on both sides. The sound system I will build for that space will use near field bass allowing higher playback levels before annoying the neighbours. The dipole radiation pattern of these subwoofers allows a null to be pointed in the direction of the neighbours too for further reduction in leakage.
The dipole bass enclosure I used was a classic W style using a pair of Scan Speak 32W/4878T00 per box. It was similar in design and proportion to the classic Linkwitz design but adjusted for the larger drivers I used:
I have some outdoor measurements of this box that shows the advantage of the near field placement. The response flattens significantly as the listening position is reduced. This plot is 0.5M, 1M and 3M from the front of the box, outdoors, no eq:
At 0.5M there is only about 5dB of correction required in its 25-80Hz passband. My testing showed the location of the near field sub could be heard with a 100Hz crossover (24dB/Oct). No intermediate crossover points were tested.
I'm couch surfing/travelling for the next year and a bit so unfortunately I'm not able to do any further testing, but I encourage anyone with interest in this topic to give it a try. The reduction in bass leakage is stunning. The next logical test would be to quantify the bass leakage for a sealed box vs a dipole at 0.5M from the listening position vs 3M from the listening position at the same LP level. These four plots would be enlightening. My simple listening tests proved to me the near field OB bass approach was a no brainer and is the approach I will follow for my new system build.
My experiments date back several years. I never measured the difference in leakage between a sealed box and a dipole at the same level. With hindsight I should have, but the difference was so dramatic I felt it was unnecessary. I was doing the experiments for my own interest and the conclusion I came to was nearfield OB bass was a no brainer for anyone who wants to control bass leakage in a medium or high density residential situation. My wife and I will be moving into a townhouse next year with an adjoining party wall to neighbours on both sides. The sound system I will build for that space will use near field bass allowing higher playback levels before annoying the neighbours. The dipole radiation pattern of these subwoofers allows a null to be pointed in the direction of the neighbours too for further reduction in leakage.
The dipole bass enclosure I used was a classic W style using a pair of Scan Speak 32W/4878T00 per box. It was similar in design and proportion to the classic Linkwitz design but adjusted for the larger drivers I used:
I have some outdoor measurements of this box that shows the advantage of the near field placement. The response flattens significantly as the listening position is reduced. This plot is 0.5M, 1M and 3M from the front of the box, outdoors, no eq:
At 0.5M there is only about 5dB of correction required in its 25-80Hz passband. My testing showed the location of the near field sub could be heard with a 100Hz crossover (24dB/Oct). No intermediate crossover points were tested.
I'm couch surfing/travelling for the next year and a bit so unfortunately I'm not able to do any further testing, but I encourage anyone with interest in this topic to give it a try. The reduction in bass leakage is stunning. The next logical test would be to quantify the bass leakage for a sealed box vs a dipole at 0.5M from the listening position vs 3M from the listening position at the same LP level. These four plots would be enlightening. My simple listening tests proved to me the near field OB bass approach was a no brainer and is the approach I will follow for my new system build.
Thats great info thanks. I hope you have a great year of traveling and enjoy beautiful places that are relatively free of the packaged masses with the COVID downturn in tourism.
I see on your web site you have generousy shared your extensive experience with differnt bass builds, from tapped horns to IB. I read OB bass is different as the room is not pressurized. I wonder if you actually got a feel for the experiential quality of the OB bass? Does it sound or feel different?