Hi Scruffyht,
Can't see why not. Main difference would be the location of the terminus (vent).
Regards,
Can't see why not. Main difference would be the location of the terminus (vent).
Regards,
Well, thank you...If I'm interpreting the graphs correctly, T-TQWT would have a flatter response as you go below 30Hz. My sealed subs need a bit of equalization to keep a reasonably flat response. (I use a BFD Equalizer)
As you might guess, most of the time my subs are loafing.
I am impressed though with the T-TQWT design, even though my aging ears don't hear much at 12Hz, even though it seems the drivers can easily get that low in the simulation. (and you only simulated it with one driver) I can tell you for sure you can feel it.
I can share with you that I had to weatherstrip the closet doors in my theater, as they vibrated in their door frames at about 17Hz so much they were a distraction.
As I said earlier, these designs are more than sufficient for our home theaters. (most people do not know what they are missing) thanks again.
I'll be curious to see what can be done with the 10" height requirement the original post requires.
Joe L.
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Hi bjorno,
Your Hornresp simulations in Post #22 have Vtc and Atc values. Is this intentional?
Regards,
Your Hornresp simulations in Post #22 have Vtc and Atc values. Is this intentional?
Regards,
Hi Oliver,
Yes,I calculated with a double thickness of the internal divider, i.e. 2 x 18 mm Ply for the sturdiness of the enclosure baffle and to gain some driver clearance too.
b🙂
Hi Oliver ... can we model it with the vent in the back corner as you suggested?
Thanks
Steve
Any chance you guys can help with the dimensions of the box ... would be appreciated? ... dual or single tang band drivers like what permo used?
Thanks
Thanks
Hi Scruffyht,
I've been trying to find the time to look at this with Hornresp and AkAbak.
When I use Hornresp I can arrive at a smoother response with the port slightly out of the corner (venting to the top in the middle between the two drivers), and a slightly longer tube path. The result looks reasonable. Trying to enter this into AkAbak I have not had any success duplicating the Hornresp result. I get the SPL boost you would expect from a corner, but do not get the smooth extended response I get in Hornresp (which results from shortening the L34 distance, i.e.: moving the port closer to the middle of the drivers). The shape of the SPL curve in AkAbak looks a lot like the 2pi response for the same enclosure in AkAbak while the response in Hornresp is a lot "cleaner" in 0.5pi than in 2pi.
Anyway, I'll attach a Hornresp input screen, and the 2pi/0.5pi SPL comparison. I'm not sure when I'll find the time to improve on the modelling in AkAbak; but from this simulation, and hopefully bjorno's input, we should be able to arrive at a folding/stuffing that should work for you. The dimensions always change a little when you transfer from paper to wood. I don't mind doing the drawing, but I want to wait to see what bjorno has to say to this simulation.
Bye the way, do you have a supplier for this driver?
Regards,
I've been trying to find the time to look at this with Hornresp and AkAbak.
When I use Hornresp I can arrive at a smoother response with the port slightly out of the corner (venting to the top in the middle between the two drivers), and a slightly longer tube path. The result looks reasonable. Trying to enter this into AkAbak I have not had any success duplicating the Hornresp result. I get the SPL boost you would expect from a corner, but do not get the smooth extended response I get in Hornresp (which results from shortening the L34 distance, i.e.: moving the port closer to the middle of the drivers). The shape of the SPL curve in AkAbak looks a lot like the 2pi response for the same enclosure in AkAbak while the response in Hornresp is a lot "cleaner" in 0.5pi than in 2pi.
Anyway, I'll attach a Hornresp input screen, and the 2pi/0.5pi SPL comparison. I'm not sure when I'll find the time to improve on the modelling in AkAbak; but from this simulation, and hopefully bjorno's input, we should be able to arrive at a folding/stuffing that should work for you. The dimensions always change a little when you transfer from paper to wood. I don't mind doing the drawing, but I want to wait to see what bjorno has to say to this simulation.
Bye the way, do you have a supplier for this driver?
Regards,
Attachments
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Hi Oliver,
The cure is to remove a foot from the closed end or stuff the first foot with very dense damping material like dense Rockwool 1-2lb/ft^3 =16-24kg/m^3.
This could be simulated in AKAbak too by changing the waveguide sections into Ducts and invoke the 'damping material' switches.
b🙂
Attachments
Hi bjorno,
Thanks, that will give me a starting point. Now, I just have to steal some time somewhere.
Regards,
Thanks, that will give me a starting point. Now, I just have to steal some time somewhere.
Regards,
Hi Scruffyht,
I found some extra time today.
This will give you an option to the enclosure permo build. Both enclosures would work fine for your application, this one will go a little lower, and - surprise - it is a little bigger. The port can be located as in this drawing (symmetrically with the drivers), or can be pushed to the end of the duct, all the way into the corner; the resulting difference in response can be retuned with the stuffing.
The stuffing is the key to tuning the response. bjorno uses MLK's spreadsheets to calculate the stuffing density and distribution, so that gives you an easy starting point. You will have to spend some time figuring out how to keep the fiberfill away from the drivers; maybe a wire cage over the front of the upper driver, and some cheesecloth over the back of the lower driver.
As any other vented speaker, this subwoofer should be use with a low-cut filter, something to keep in mind.
Hope this helps.
Regards,
I found some extra time today.
This will give you an option to the enclosure permo build. Both enclosures would work fine for your application, this one will go a little lower, and - surprise - it is a little bigger. The port can be located as in this drawing (symmetrically with the drivers), or can be pushed to the end of the duct, all the way into the corner; the resulting difference in response can be retuned with the stuffing.
The stuffing is the key to tuning the response. bjorno uses MLK's spreadsheets to calculate the stuffing density and distribution, so that gives you an easy starting point. You will have to spend some time figuring out how to keep the fiberfill away from the drivers; maybe a wire cage over the front of the upper driver, and some cheesecloth over the back of the lower driver.
As any other vented speaker, this subwoofer should be use with a low-cut filter, something to keep in mind.
Hope this helps.
Regards,
Thanks Oliver!
couple questions ... where can I find MLK spreadsheet for stuffing and where can I buy stuffing? ... also what low cut filter do you recommend as well as how big a amp do I need to run 2 of these subs?
Thanks again
Steve
couple questions ... where can I find MLK spreadsheet for stuffing and where can I buy stuffing? ... also what low cut filter do you recommend as well as how big a amp do I need to run 2 of these subs?
Thanks again
Steve
Hi Scruffyht,
Sorry, MLK is a typo, it should be MJK for Martin J. King: Quarter Wavelength Loudspeaker Design
Google for: Fiberfill - Poly-Fil - polyester batting.
Widely available, Walmart, Parts-Express, fabric stores, e.g.: Quilt Batting, Poly-Pellets, Foam, Upholstery Supplies, Replacement Cushions.
Batting and bulk fiber both come in handy.
Your usage, and your system will ultimately determine the amplification and filtering; I would say that a starting point is 15Hz-80Hz w/ 24dB slopes (4the order), and 300W per box.
When testing speakers do not use sine waves at high power. Test at levels you are comfortable with.....
Regards,
Sorry, MLK is a typo, it should be MJK for Martin J. King: Quarter Wavelength Loudspeaker Design
Google for: Fiberfill - Poly-Fil - polyester batting.
Widely available, Walmart, Parts-Express, fabric stores, e.g.: Quilt Batting, Poly-Pellets, Foam, Upholstery Supplies, Replacement Cushions.
Batting and bulk fiber both come in handy.
Your usage, and your system will ultimately determine the amplification and filtering; I would say that a starting point is 15Hz-80Hz w/ 24dB slopes (4the order), and 300W per box.
When testing speakers do not use sine waves at high power. Test at levels you are comfortable with.....
Regards,
Hi Oliver ... some background as I need some help in finding the right amp/filter
Speakers already have - Axiom M80 LR ... 150 center and QS8 surrounds
I have settled on the Denon 4311 11.2 receiver - still need to locate one for the $1300 price range it is available for in the states ($2200 here in Canada)
1 X CSS SDX15 driver to be used in the 13 cu ft sub that I have all the wood cut for ... just need to assemble ... that driver is no longer available and Mike P over at the shack suggested I get a TC Sounds LMS-R15 for the other box as he said they modeled for similar cabinets ... still have not pulled the trigger on the TC driver but will have to do so quickly as I am close to moving into the theatre finishing stage (still working on finishing the gym screen wall - pics to follow when complete) ... these 2 subs are to be part of the Riser
EP4000 amp is what has been recommended to run both the EP and TC subs - will pick one up when I am at that stage
So that brings us to the 2 X T TQWT for the Stage ... I have no clue as to what amplifier would work ... do I use one larger amp or do I use 2? ... is the filter a separate unit? ... a link to something from PE would be helpful
Thanks again
Steve
Speakers already have - Axiom M80 LR ... 150 center and QS8 surrounds
I have settled on the Denon 4311 11.2 receiver - still need to locate one for the $1300 price range it is available for in the states ($2200 here in Canada)
1 X CSS SDX15 driver to be used in the 13 cu ft sub that I have all the wood cut for ... just need to assemble ... that driver is no longer available and Mike P over at the shack suggested I get a TC Sounds LMS-R15 for the other box as he said they modeled for similar cabinets ... still have not pulled the trigger on the TC driver but will have to do so quickly as I am close to moving into the theatre finishing stage (still working on finishing the gym screen wall - pics to follow when complete) ... these 2 subs are to be part of the Riser
EP4000 amp is what has been recommended to run both the EP and TC subs - will pick one up when I am at that stage
So that brings us to the 2 X T TQWT for the Stage ... I have no clue as to what amplifier would work ... do I use one larger amp or do I use 2? ... is the filter a separate unit? ... a link to something from PE would be helpful
Thanks again
Steve
Hi Scruffyht,
To start with, I'm really not up-to-date on what is out there in the amplifier world, and there are so many different possibilities that I guess you're in for some research.
At PE I have noticed the SA1000 which has ample power for these two subs (both subs in parallel would be a 4-Ohm load). I like the form factor, the input/output connection flexibility, the filter/equalizer functionality, and it has a 12V trigger input which may come in handy in a HT system. This looks to be a much easier solution than e.g.: independent plate amplifiers with a minidsp. I recommend you download the manual, and read the reviews.
Regards,
To start with, I'm really not up-to-date on what is out there in the amplifier world, and there are so many different possibilities that I guess you're in for some research.
At PE I have noticed the SA1000 which has ample power for these two subs (both subs in parallel would be a 4-Ohm load). I like the form factor, the input/output connection flexibility, the filter/equalizer functionality, and it has a 12V trigger input which may come in handy in a HT system. This looks to be a much easier solution than e.g.: independent plate amplifiers with a minidsp. I recommend you download the manual, and read the reviews.
Regards,
Hi Scruffyht,
Just another item, the Behringer iNUKE DSP amplifiers, the DSP section looks quite sophisticated, e.g.: Behringer NU1000DSP iNUKE 1000 Watt Power Amplifier w/DSP 248-6702
Regards,
Just another item, the Behringer iNUKE DSP amplifiers, the DSP section looks quite sophisticated, e.g.: Behringer NU1000DSP iNUKE 1000 Watt Power Amplifier w/DSP 248-6702
Regards,
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