Still burning daylight
Au contraire sreten...
The OP's selection of Mini-DSP active crossover combined with the other general technical parameters I listed are enough to get serious about selecting a driver. As for 40L being "far too big", that is up to the OP. I consider the 40L kinda like a speed limit set by the OP for what ever reasons. What is important about the 40L value is that there are quite a few 8" drivers that will work well with in the 40L limit. It is possible to go smaller depending on the actual driver selected and other factors dictated by the rest of the system. Also, if efficiencies above, say 90 dbw are appropriate to better mate with the rest of the system, 40L quickly becomes a MINIMUM sized box.
BSC is a valid consideration and will be baffle configuration dependent. However, for all we know the OP may be considering a shallow depth, wide baffle design where BSC is not an issue. I am just try to move things along. This is a band - pass mid-woofer application and the DSP can handle what ever is needed.
My point is until you select a driver or drivers to model, NOTHING can move forward. And there is enough known at this point to move forward with that.
Au contraire sreten...
The OP's selection of Mini-DSP active crossover combined with the other general technical parameters I listed are enough to get serious about selecting a driver. As for 40L being "far too big", that is up to the OP. I consider the 40L kinda like a speed limit set by the OP for what ever reasons. What is important about the 40L value is that there are quite a few 8" drivers that will work well with in the 40L limit. It is possible to go smaller depending on the actual driver selected and other factors dictated by the rest of the system. Also, if efficiencies above, say 90 dbw are appropriate to better mate with the rest of the system, 40L quickly becomes a MINIMUM sized box.
BSC is a valid consideration and will be baffle configuration dependent. However, for all we know the OP may be considering a shallow depth, wide baffle design where BSC is not an issue. I am just try to move things along. This is a band - pass mid-woofer application and the DSP can handle what ever is needed.
My point is until you select a driver or drivers to model, NOTHING can move forward. And there is enough known at this point to move forward with that.
I was thinking of these for the 3 way :
GF200 Visaton 20 cm (8 inch) High-End woofer with double voice-coil
GF200 - Visaton 20 cm (8 inch) High-End woofer with double voice-coil - Europe Audio
Scan Speak 10F/8424G00
10F/8424G00 - Scan-Speak 4 inch wideband coated fiberglass - Europe Audio
Scan Speak D2608/913000
D2608/913000 - Scan-Speak 1 inch dome tweeter fabric diaphragm - Europe Audio
for the box i can go maximum of 45L , but it can be smaller , my room is small 15m2 or 49 sq feet , thats why i dont want bigger boxes
oh and the wife too
GF200 Visaton 20 cm (8 inch) High-End woofer with double voice-coil
GF200 - Visaton 20 cm (8 inch) High-End woofer with double voice-coil - Europe Audio
Scan Speak 10F/8424G00
10F/8424G00 - Scan-Speak 4 inch wideband coated fiberglass - Europe Audio
Scan Speak D2608/913000
D2608/913000 - Scan-Speak 1 inch dome tweeter fabric diaphragm - Europe Audio
for the box i can go maximum of 45L , but it can be smaller , my room is small 15m2 or 49 sq feet , thats why i dont want bigger boxes
oh and the wife too
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How in god's name is a personal observation like this going to get people into trouble? I did not say you WILL get Fc twice Fs. Nor is what I wrote of any use in deciding on a box or anything else for that matter.
I refoam a lot of woofers, WT2 test Fs, put them in the commercial AS boxes they came out of and voila! A subsequent response test shows the LF elbow at around twice the Fs value almost all of the time. Maybe it's just coincidence on my part, but for most of the AS speakers I've worked on, the a Fc/Fs ratio corresponds to an alpha of about 3, right were Dickason passes the AS baton off to IB in the LSDCB.
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Hi,
I disagree. The miniDSP was mentioned as the sub/sat x/o.
No technical details have been provided by the OP other
than he can go up to 45L, but that is simply not needed.
You can't move forward on the bass unit without the overall
3-way design. I assume the 3-ways should work well without
any help from the DSP, though using the DSP for tunable BSC
seems a good idea and perhaps a bit more, see Hybrid Design
For a good 3-way design a sealed version is usually trivial.
rgds, sreten.
It sounded like one of those design rules. "Putting the woofer in the cabinet will raise the -3dB point one Octave". There is no theory to support that but if it a general observation then okay. It sounds much like "Q will go up by a factor of 1.4" earlier in the thread. Or "sealed boxes need a high Q woofer to start with".
If people are going to learn about speaker design here then we need to be careful about the information being spread around.
David S.
I don't think forums are the place to learn about speaker design. I first read Weems, LDCB and others. OTOH, there are a lot of lazy people in the world who'll trust just about anyones 'advice' as long as they don't have to spend the time to do some research.
One of my pet peeves is the thread titled: "What's the BEST........?"
Hello
Take a look at these mid woofer
SPH-200KE - Monacor top HiFi bass-midrange speaker 120Wmax 8 Ohm - Europe Audio
I have a pair, not bad at all
Greetings Gabor
Take a look at these mid woofer
SPH-200KE - Monacor top HiFi bass-midrange speaker 120Wmax 8 Ohm - Europe Audio
I have a pair, not bad at all
Greetings Gabor
The orriginal post asked for a woofer recomendation and you, (post #2) launched into a "theory of acoustic suspension design" reply. Unfortunately your information was largely wrong and several of us jumped in to correct it.
I do think a significant value of this forum is the dissemination of good design theory. (Of the "Teach a man to fish..." approach.) not every question needs a design treatise as an answer, but when theory is offered it should be correct.
David S.
I looked at Felipe's Visaton GF200. It's really a driver suited for reflex around 40-45L.
Visaton - Lautsprecher und Zubehör, Loudspeakers and Accessories
It's the Qts of 0.34 and Vas of 68L that tells you an acoustic suspension design would be around 22L. You'd want a softer surround and a bigger Vas for any closed box solution near 40L, if I have any understanding of the simple calculation.
In confirmation, Visaton offer a 40L reflex design for this driver called the Classic:
Visaton - Lautsprecher und Zubehör, Loudspeakers and Accessories
The suggested Monacor SPH-200KE has similar low Qts of 0.38 and Vas of 54L, so is maximally flat around 20-25L enclosure.
SPH-200KE - Monacor top HiFi bass-midrange speaker 120Wmax 8 Ohm - Europe Audio
I'd guess a suitable driver for closed box is really going to be Qts=0.5 and Vas 50L here, unless you look for a foamed surround low Qts driver like the old acoustic research drivers, which had enormous voice coil inductance (3mH...) and magnets. Closed box is quite unfashionable these days, so you have to hunt around for a driver.
Visaton - Lautsprecher und Zubehör, Loudspeakers and Accessories
It's the Qts of 0.34 and Vas of 68L that tells you an acoustic suspension design would be around 22L. You'd want a softer surround and a bigger Vas for any closed box solution near 40L, if I have any understanding of the simple calculation.
In confirmation, Visaton offer a 40L reflex design for this driver called the Classic:
Visaton - Lautsprecher und Zubehör, Loudspeakers and Accessories
The suggested Monacor SPH-200KE has similar low Qts of 0.38 and Vas of 54L, so is maximally flat around 20-25L enclosure.
SPH-200KE - Monacor top HiFi bass-midrange speaker 120Wmax 8 Ohm - Europe Audio
I'd guess a suitable driver for closed box is really going to be Qts=0.5 and Vas 50L here, unless you look for a foamed surround low Qts driver like the old acoustic research drivers, which had enormous voice coil inductance (3mH...) and magnets. Closed box is quite unfashionable these days, so you have to hunt around for a driver.
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Nice work, Pano!OT posts removed. Let's keep the comments to speaker building, please.
I think the point for Felipe's original question is that a driver designed for closed box is really a different animal from a driver designed for reflex.
For closed box you can use a much lower inductance (say 0.3mH or less) which is good for extending frequency response, higher Qts and a softer surround, all of which help integrate the design. Worth looking around for something appropriate, though I really don't want to spend time on it myself. I'd suspect the appropriate single driver for 40L closed box is likely going to be found in the 10-12" range.
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Just my OCD nature, but I looked into the 40L closed box drivers at Wilmslow Audio in the UK.
Mid/Bass Units
Peerless do a Qts=0.5 8" suitable for 33L maximally flat response, a 10" suitable for 70L and a 12" for 175L (which is 6 cubic feet!). 40L closed is just a very bad design choice based on what most companies actually make, and you really only get 20% leeway on going below Vas by adding damping!
FWIW, the old foamed Vifa M21WG-09-08, used by Heybrook amongst others, is a very odd animal with a Qts of 0.7.
Vifa M21WG-09-08
You really can't get that one flat at all in any reasonable box...
Mid/Bass Units
Peerless do a Qts=0.5 8" suitable for 33L maximally flat response, a 10" suitable for 70L and a 12" for 175L (which is 6 cubic feet!). 40L closed is just a very bad design choice based on what most companies actually make, and you really only get 20% leeway on going below Vas by adding damping!
FWIW, the old foamed Vifa M21WG-09-08, used by Heybrook amongst others, is a very odd animal with a Qts of 0.7.
Vifa M21WG-09-08
You really can't get that one flat at all in any reasonable box...
A solid recommendation
OK, Going to assume the Peerless 8" 830869 driver is currently available through Europe Audio. It is listed there at $91.00 USD.
This is a great woofer with a smooth extended response, has a combination of FS and VAS needed to fit within the 40L enclosure limit. Excellent reviews, nice off axis response, nomex diaphragm, Faraday motor enhancement, and other excellent tech features.
Flexible, can be used as a pure woofer, mid woofer or dedicated mid range.
Hard to beat. No special crossover tricks (or DSP) to work well. Nice cast frame too.
Very low distortion.
OK, Going to assume the Peerless 8" 830869 driver is currently available through Europe Audio. It is listed there at $91.00 USD.
This is a great woofer with a smooth extended response, has a combination of FS and VAS needed to fit within the 40L enclosure limit. Excellent reviews, nice off axis response, nomex diaphragm, Faraday motor enhancement, and other excellent tech features.
Flexible, can be used as a pure woofer, mid woofer or dedicated mid range.
Hard to beat. No special crossover tricks (or DSP) to work well. Nice cast frame too.
Very low distortion.
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