I just build speakers for my new place that are literally screwed on the wall, with 4x 8W1v3 subwoofers + PR, 6.5'' deep, protective grills included. Flat from 25hz, probably north of 110db @ listening position.
I'd ask, "Which kind of mounting would be the most interesting to play with?".
As much as I pooh-pooh the sound quality of BRs, I think OP could best fool with one of these which are (relatively) easy to modify as to stuffing, port resistance (ARU), and all kinds of port permutations. Second most foolable fun would be a pipe/labyrinth.
Or..... I'd make a sealed box and explore room acoustics and treatments.
B.
As much as I pooh-pooh the sound quality of BRs, I think OP could best fool with one of these which are (relatively) easy to modify as to stuffing, port resistance (ARU), and all kinds of port permutations. Second most foolable fun would be a pipe/labyrinth.
Or..... I'd make a sealed box and explore room acoustics and treatments.
B.
Despite the title, the questionning is not really about which box type (or OB) is better for low frequencies only.
I think the question of sub-100hz optimal solutions are pretty settled, no?
Passive radiators, if cost is no object.
and 4th order bandpass or exotic enclosures if absolute highest output at a very low frequency is the goal.
But what about a woofer that is ALSO entering midrange territory?
How do you handle both: decent low frequency performance AND clean midrange, all in the same box (or OB) ?
I think the question of sub-100hz optimal solutions are pretty settled, no?
Passive radiators, if cost is no object.
and 4th order bandpass or exotic enclosures if absolute highest output at a very low frequency is the goal.
But what about a woofer that is ALSO entering midrange territory?
How do you handle both: decent low frequency performance AND clean midrange, all in the same box (or OB) ?
Build a very large, very rigid box. Or build big OB. The clean midrange has a better chance in OB. Both can work well, but sound different.
Here Here!
Well said John I totally agree!
Whats more, Tony agrees with you and he is a bass player and internationally respected loudspeaker designer. " Purely based on musicality, I would have chosen the U frame" (open baffle)
http://www.humblehomemadehifi.com/download/Humble Homemade Hifi_Serious Sub.pdf
One caveat in my experience, you need to have a min of 4 feet from the rear of the bass driver to the back wall.
Well said John I totally agree!
Whats more, Tony agrees with you and he is a bass player and internationally respected loudspeaker designer. " Purely based on musicality, I would have chosen the U frame" (open baffle)
http://www.humblehomemadehifi.com/download/Humble Homemade Hifi_Serious Sub.pdf
One caveat in my experience, you need to have a min of 4 feet from the rear of the bass driver to the back wall.
I tried direct wall mounted woofers. They shook the wall to massive distortion. Went push pull to counter balance then all was good.
BR is better with big enough port and tuned below 30hz. That takes a big box with proper woofer for proper 30hz tuning. Using a 5" woofer tuned to 45hz with tiny port can cause the problems people associate with BR.
That said one of the few systems I heard port noise with was the HPM100s. A poorly designed over rated system.
That said one of the few systems I heard port noise with was the HPM100s. A poorly designed over rated system.
An alternative box, which was used by Bigun for a 15" fullrange driver is the Boffle. His design and construction journey are in this thread:
A Big'un - the Audio Nirvana Super 15
A Big'un - the Audio Nirvana Super 15
Yes, ain't easy I agree.
Is used 4x thick rubber gaskets per box to absorb the vibrations and secured everything with 1/4 screws in the wall. It's extremely rigid.
And frankly, I can't remember the last time I had such clean and tight bass. I'm very impressed.
Big subs require a big anchor!
Good point Jon,
High power subs really do need to be solidly anchored.
The physics is similar to the WW2 battle ships when the fired the 1 ton shells 15 miles onto the beach... "For every action there is an equal and opposite reaction"
If you have a massive 18 inch pro driver powered with a 2 or 3 Kw power amp that's going to need a big anchor, and if I remember you run 3 of them!
Good point Jon,
High power subs really do need to be solidly anchored.
The physics is similar to the WW2 battle ships when the fired the 1 ton shells 15 miles onto the beach... "For every action there is an equal and opposite reaction"
If you have a massive 18 inch pro driver powered with a 2 or 3 Kw power amp that's going to need a big anchor, and if I remember you run 3 of them!
Most of us are in the same boat - I understand. I've been lucky enough to have had some listening spaces where size was not an issue. I miss those spaces. 🙁
At the moment I only run 4x JL audio 8w1v3 with 12's passive radiators, it's really not WW2 stuff 😀
I had before 4x 10W7 with 4kw and that was a little bit more intense, but wasnt wall mounted though.
I still have those big monstrous speakers at my place of work (16' tall) so when I have some megalomaniac urges I know where to go 😛
But for my home, I'd rather keep it simple and small.
I find room gain tends to increase bottom end at 3-6 dB/octave below about 120ish Hz so I like tuning at frequencies seemingly too low for the box, which rolls off the response considerably higher than the usual case. It does rob a bit of sensitivity in the lower midbass but around 20 Hz and lower are improved. Pipe organs are great fun.
The curves below show this in action: the green line shows my default cabinet and the yellow line shows what happens when I stuff a sock in one of the two ports. The first case sounded a bit lumpy in the bottom end, with not much articulation between bass and drums. The second case, while not as immediate with WOW!ful bass, feels more transparent as bass and drums are now distinct entities. It's not exactly shy with bottom end either: both woofers turned up can rattle various bits of the house. Add in a 16 Hz highpass to keep the cones from sailing across the room, along with a touch of Linkwitz Transform, and the world is my oyster.
The curves below show this in action: the green line shows my default cabinet and the yellow line shows what happens when I stuff a sock in one of the two ports. The first case sounded a bit lumpy in the bottom end, with not much articulation between bass and drums. The second case, while not as immediate with WOW!ful bass, feels more transparent as bass and drums are now distinct entities. It's not exactly shy with bottom end either: both woofers turned up can rattle various bits of the house. Add in a 16 Hz highpass to keep the cones from sailing across the room, along with a touch of Linkwitz Transform, and the world is my oyster.
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Lots of members have posted very good points and directions. Here's my 2 cents.
With all enclosure-type speaker designs, priority should be given to absorbing the speaker driver's backward radiation with sound absorption. Think of sound absorption that you put on the room's of listening rooms, but on the inside of the cabinet.
Instead of getting reflections going back out the speaker's cone, it gets absorbed. This also possibly helps the enclosure not be excited into resonance by sound pressure. One fantastic product is standard Ultratouch Denim house insulation. The NRC coefficient for 3.5" thick insulation is crazy good.... but most people probably cant fit 3.5" on the inside of their speaker cabinet walls.
http://bondedlogic.com/pdf/denim-insulation/UltraTouch-Denim-Spec-Sheet.pdf
As for the enclosure it's self, it should be damped with mass-loading to deaden resonances. This isn't the same as sound-absorption. Think of "dynamat" type products.These are also called "CLD". An audible example video is linked.
Products | Sound Deadener Showdown
One product that combines both approaches is No-Rez, sold by GR Research. I really wish they would test the NRC though!
No Rez 24"x27" Sheet
As far as enclosure design:
Sealed boxes with QTC of .5 have optimal transient response. A QTC of .707 trades off transient response for a more extended frequency response. In reality, most people will be happy with a QTC anywhere between. 0.50 - 0.707, although some may prefer to be at one end of the range.
Ported enclosures transient response is described here.
Bass reflex alignments explained - Step by step | Audio Judgement
Basically, the SSB4 alignment or "Super Forth-Order Boom Box" has the best transient response.
Dampen port resonances with CLD on the outside of the port, and reduce midrange sound leakage with internal absorption, as stated above.
An interesting alignment, in concerns of resonances, that I have seen under researched and under developed is a aperiodic speaker. Subjective SQ reports from those who have built such boxes seem to report a reduction of resonances, and a more "natural" bass. I saw somewhere that one described it as Transmission-Line like. Personally I find this alignment extremely interesting. I think it's possibly the golden "middle ground" between OB and Sealed designs.
Aperiodic Loudspeaker Enclosure Design
Open baffle designs are very interesting, but getting adequate bass seems to be the big issue. I don't know how it would measure, but guitar speaker cabinets are sometimes "convertible" to open-baffle like. Usually the middle 1/3 of the cabinets back wall is removed, and it gives a more open presentation of a open baffle, with some more low end than a flat plane OB design. (because it's basically an U baffle with partial back walls)
https://youtu.be/ZFBUDUNHwAY
With all enclosure-type speaker designs, priority should be given to absorbing the speaker driver's backward radiation with sound absorption. Think of sound absorption that you put on the room's of listening rooms, but on the inside of the cabinet.
Instead of getting reflections going back out the speaker's cone, it gets absorbed. This also possibly helps the enclosure not be excited into resonance by sound pressure. One fantastic product is standard Ultratouch Denim house insulation. The NRC coefficient for 3.5" thick insulation is crazy good.... but most people probably cant fit 3.5" on the inside of their speaker cabinet walls.
http://bondedlogic.com/pdf/denim-insulation/UltraTouch-Denim-Spec-Sheet.pdf
As for the enclosure it's self, it should be damped with mass-loading to deaden resonances. This isn't the same as sound-absorption. Think of "dynamat" type products.These are also called "CLD". An audible example video is linked.
Products | Sound Deadener Showdown
One product that combines both approaches is No-Rez, sold by GR Research. I really wish they would test the NRC though!
No Rez 24"x27" Sheet
As far as enclosure design:
Sealed boxes with QTC of .5 have optimal transient response. A QTC of .707 trades off transient response for a more extended frequency response. In reality, most people will be happy with a QTC anywhere between. 0.50 - 0.707, although some may prefer to be at one end of the range.
Ported enclosures transient response is described here.
Bass reflex alignments explained - Step by step | Audio Judgement
Basically, the SSB4 alignment or "Super Forth-Order Boom Box" has the best transient response.
Dampen port resonances with CLD on the outside of the port, and reduce midrange sound leakage with internal absorption, as stated above.
An interesting alignment, in concerns of resonances, that I have seen under researched and under developed is a aperiodic speaker. Subjective SQ reports from those who have built such boxes seem to report a reduction of resonances, and a more "natural" bass. I saw somewhere that one described it as Transmission-Line like. Personally I find this alignment extremely interesting. I think it's possibly the golden "middle ground" between OB and Sealed designs.
Aperiodic Loudspeaker Enclosure Design
Open baffle designs are very interesting, but getting adequate bass seems to be the big issue. I don't know how it would measure, but guitar speaker cabinets are sometimes "convertible" to open-baffle like. Usually the middle 1/3 of the cabinets back wall is removed, and it gives a more open presentation of a open baffle, with some more low end than a flat plane OB design. (because it's basically an U baffle with partial back walls)
https://youtu.be/ZFBUDUNHwAY
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Thank you Xaborus for your input, very interesting and much appreciated, especially this:
compared to that product, that use the same ASTM C423:
that I mention in the topic I just started...
Someone tried Rock Wool SAFE 'N SOUND for Mid or Woofer?
It's interesting to see that doubling the thickness has little, no effect or NEGATIVE effect on some frequencies...
An externally hosted image should be here but it was not working when we last tested it.
compared to that product, that use the same ASTM C423:
that I mention in the topic I just started...
Someone tried Rock Wool SAFE 'N SOUND for Mid or Woofer?
It's interesting to see that doubling the thickness has little, no effect or NEGATIVE effect on some frequencies...
No problem JonBocani!
The BondedLogic product has the highest NRC profile of any product I've seen on the market. Its normal house insulation, so it should very readily available. And kid-friendly too!
If you find a project that you want to do this on, but cant fit the 3.5" bonded logic or your 3" rockwool, this is the highest performance 2" product I've found.
https://www.soundproofcow.com/skin/common_files/pdf/echo_absorber_acoustic_panel_pds.pdf
The BondedLogic product has the highest NRC profile of any product I've seen on the market. Its normal house insulation, so it should very readily available. And kid-friendly too!
If you find a project that you want to do this on, but cant fit the 3.5" bonded logic or your 3" rockwool, this is the highest performance 2" product I've found.
https://www.soundproofcow.com/skin/common_files/pdf/echo_absorber_acoustic_panel_pds.pdf