Hi,
I've got 4 SBacoustics SW26DBAC76-3-DV 10" subwoofers.
These are shallow subwoofers and do work in small boxes, however, that is kind of inconvenient when tuning the boxes too low as the port is quite large...
These will be used in a (very) small room for home theater/movies, and I would really like them tuned as low as possible.
What alignment would you recommend? Sealed? Ported? Tuned @ Hz?
Should I try a tapped horn design (never got a hold to Hornsrep)?
Bandpass?
Selaed and throw a ton of power?
Here is an SPL chart @ 100W, cone excusrion and TFM
Green = Vented 27 liters tuned @25Hz
Red = Vented 30 liters tuned @ 19.5Hz
Blue = Sealed 50 liters
SB Acoustics SW26DBAC76 - 10" Shallow Subwoofer
Cheers
I've got 4 SBacoustics SW26DBAC76-3-DV 10" subwoofers.
These are shallow subwoofers and do work in small boxes, however, that is kind of inconvenient when tuning the boxes too low as the port is quite large...
These will be used in a (very) small room for home theater/movies, and I would really like them tuned as low as possible.
What alignment would you recommend? Sealed? Ported? Tuned @ Hz?
Should I try a tapped horn design (never got a hold to Hornsrep)?
Bandpass?
Selaed and throw a ton of power?
Here is an SPL chart @ 100W, cone excusrion and TFM
Green = Vented 27 liters tuned @25Hz
Red = Vented 30 liters tuned @ 19.5Hz
Blue = Sealed 50 liters
SB Acoustics SW26DBAC76 - 10" Shallow Subwoofer
Cheers
Attachments
Thanks!
I've modelled it with some PR (those among a reasonable price --> Dayton and the cheap ones from SBacoustics) and it did not modelled "that" good or maybe not that better that vented with a manageable port...
OTH, sealed with DSP and lots of power seems the better choice, right? Power is cheap these days and so is DSP. The think that keeps bothering me is the cone excursion in a sealed alignment when applying a Linkwitz Transform to a "fp" around 20Hz, i am afraid I will kill the driver. Maybe I should aim for an "fp" around 30Hz and rely on room gain for the performance under 30Hz as four of these driver should pressurize my small room without a problem.
What about 6th order BP? Or tapped horn?
I've modelled it with some PR (those among a reasonable price --> Dayton and the cheap ones from SBacoustics) and it did not modelled "that" good or maybe not that better that vented with a manageable port...
OTH, sealed with DSP and lots of power seems the better choice, right? Power is cheap these days and so is DSP. The think that keeps bothering me is the cone excursion in a sealed alignment when applying a Linkwitz Transform to a "fp" around 20Hz, i am afraid I will kill the driver. Maybe I should aim for an "fp" around 30Hz and rely on room gain for the performance under 30Hz as four of these driver should pressurize my small room without a problem.
What about 6th order BP? Or tapped horn?
A simple lightly stuffed 2:1 CR offset driver pipe tuned to ~19.5 Hz is 433 cm axial length, ~ 67.55 L net, so folded in half makes a small/tall sub if singles spread around the room with the trade-off of the driver not being close enough to the floor for good 2pi loading.
A 19.5 Hz TH is 545 cm, ~113.4 L, so has a bit more low end with a bit lower XO point.
A 19.5 Hz TH is 545 cm, ~113.4 L, so has a bit more low end with a bit lower XO point.
I've found a couple of Passive Radiators that might do the trick (price and performance wise).
1-. Earthquake Sound Slaps 10 --> Using a single PR and after some small DSP PEQ it models quite good in WinISD
2-. Dayton Audio DSA270-PR 10" Designer Series Aluminum Cone Passive Radiator --> 2 of these give me good performance around 25Hz after some PEQ in WinISD.
Both of these choices are around USD$65 each, whereas the SLAPS10 gives better performance (small margin) in a smaller box (sadly, is ugly as hell).
Red is Dayton.
1-. Earthquake Sound Slaps 10 --> Using a single PR and after some small DSP PEQ it models quite good in WinISD
2-. Dayton Audio DSA270-PR 10" Designer Series Aluminum Cone Passive Radiator --> 2 of these give me good performance around 25Hz after some PEQ in WinISD.
Both of these choices are around USD$65 each, whereas the SLAPS10 gives better performance (small margin) in a smaller box (sadly, is ugly as hell).
Red is Dayton.
Attachments
Yes, but..... seems like damping the vent harmonics may all but 'kill' its efficiency.
Do you think a vented alignment with a long slot port (over 1 meter) is a better alternative?
I think I can manage a "labyrinth" type slot port with an air speed under 17 m/s when applying over 200W, and keeping the port resonances over 150Hz (subs will be crossed around 80-90Hz @ 2nd or 4th order, but I really don't know If I will have another problems with a long sloted port.
On the other hand, an Earthquake Sound Slaps M12 Passive radiator is enough to offer me similar performance and the choice of change the tuning with just adding or substracting some weight... given it's an extra USD$60 per SW
I think I can manage a "labyrinth" type slot port with an air speed under 17 m/s when applying over 200W, and keeping the port resonances over 150Hz (subs will be crossed around 80-90Hz @ 2nd or 4th order, but I really don't know If I will have another problems with a long sloted port.
On the other hand, an Earthquake Sound Slaps M12 Passive radiator is enough to offer me similar performance and the choice of change the tuning with just adding or substracting some weight... given it's an extra USD$60 per SW
No, I'm a believer that if a vented box needs a long/large vent for a low vent mach, then morph the two into an inverse tapered TL [TQWT] and if necessary, fine tune it with a vent [ML-TQWT].
I like PRs only if really low tuned [< ~20 Hz]. FWIW, I use to have a pair of these till I found out the hard way that my old home has an Fs of ~14 Hz: servo drive contrabass subwoofer - Google Search
I like PRs only if really low tuned [< ~20 Hz]. FWIW, I use to have a pair of these till I found out the hard way that my old home has an Fs of ~14 Hz
: servo drive contrabass subwoofer - Google SearchAfter lot's of modelling and realizing a tapered TL is beyond my wood skills, I think the best is going vented and tune it @23Hz in a 49 liter box, which gives me good bass extension, good power management and kind of low air speed and also is the easiest and cheapest to build (compared to TL and PR).
I attached a SPL chart from WinISD for vented (red), PR (purple) and 6thBP (cyan), all @ full power limited to cone excursion and all with minimum and broad PEQ and HP for a flat anechoic response.
These vented alignment gives me a 918.8mm long, 290mm wide 30mm tall slot port. Also, considering post #31 in this thread:
Slot port enclosures: successes and failures, please post... | Page 2 | AVS Forum
It seems WinISD does not model correctly the sloted port, and I should go around 10% shorter than what it says... a 900mm long port does not seem that bad and also resonance is around 180Hz, well above my crossover point. Air velocity is around 21 m/s @ full power (250W limited by cone excursion).
It seems that good trade off. What do you think?
4 of these in a small room should offer a good performance (no, you will not loose your teeth with this bass, but it will be enjoyable I think).
I attached a SPL chart from WinISD for vented (red), PR (purple) and 6thBP (cyan), all @ full power limited to cone excursion and all with minimum and broad PEQ and HP for a flat anechoic response.
These vented alignment gives me a 918.8mm long, 290mm wide 30mm tall slot port. Also, considering post #31 in this thread:
Slot port enclosures: successes and failures, please post... | Page 2 | AVS Forum
It seems WinISD does not model correctly the sloted port, and I should go around 10% shorter than what it says... a 900mm long port does not seem that bad and also resonance is around 180Hz, well above my crossover point. Air velocity is around 21 m/s @ full power (250W limited by cone excursion).
It seems that good trade off. What do you think?
4 of these in a small room should offer a good performance (no, you will not loose your teeth with this bass, but it will be enjoyable I think).
Attachments
Hmm, just noticed that your vent will have some acoustic damping due to its high 29/3 = ~ 9.67:1 CR.
FYI, vent harmonics will comb filter with the driver's outputs regardless of XO point. The pioneer's solution, the click test: Click Test | GM210 | Flickr
FYI, vent harmonics will comb filter with the driver's outputs regardless of XO point.
The pioneer's solution, the click test: Click Test | GM210 | Flickr Sorry man, I literally did not understand anything from your post! Well, only comb filter.
Should I go with rounded port then? Or just toss some "polyfill" on the slotted port?
I might be able to fit 2x 3" ports with similar length and flared ends... that would mean around 5 m/s higher vent speed at full power.
Should I go with rounded port then? Or just toss some "polyfill" on the slotted port?
I might be able to fit 2x 3" ports with similar length and flared ends... that would mean around 5 m/s higher vent speed at full power.
That's OK, in my haste I posted CR [compression ratio] since I was also responding to a horn Q on the phone, but meant AR [aspect ratio], i.e. once a pipe's shape moves away from round it becomes increasingly less efficient and according to heat/AC duct design, 9:1 AR is the [rule of thumb?] point where duct noise from friction combined with unacceptable blower efficiency loss.
Well, in Hornresp
the vent mach [speed] is good for 100 W, but sims 200 W capable with a too high vent mach, hence using the click test to 'critically' damp it. This is an easy way to get 'just enough' damping with least vent gain loss by ear or you can use an impulse response if you're set up to measure.
While flared ends help if large enough, there's still a bend, though loss through round isn't [nearly?] as much as a high AR duct.
Anyway, all you need to know, but afraid to ask: https://www.diyaudio.com/forums/att...a_slotport-calc_omnes-audio_w8-670z_ml-tl-jpg
Well, in Hornresp
the vent mach [speed] is good for 100 W, but sims 200 W capable with a too high vent mach, hence using the click test to 'critically' damp it. This is an easy way to get 'just enough' damping with least vent gain loss by ear or you can use an impulse response if you're set up to measure.
While flared ends help if large enough, there's still a bend, though loss through round isn't [nearly?] as much as a high AR duct.
Anyway, all you need to know, but afraid to ask
: https://www.diyaudio.com/forums/att...a_slotport-calc_omnes-audio_w8-670z_ml-tl-jpg