T-TQWT for a theatre stage

[Scruffyht]

Hi,

FYI, An powerful OD T-TQWT suggestion using 2x CSS-SDX15 drivers:

b🙂

Bjorno ... can you give me a idea how big a box I would need to build this? ... only restriction is height of 16" or less

Thanks

Steve

 

[bjorno]

Bjorno ... can you give me a idea how big a box I would need to build this? ... only restriction is height of 16" or less

Thanks

Steve

Hi Steve,

Have a look at Picture 1. Are you aware of the frame Width of the drivers ( 15” 5/16): You have to 'DIY' decide on if to use a slanted baffle and provide the actual drawing dimensions at S2 and S3.

FYI.A couple of years ago I designed a small piggy-back T-TQWT with a slanted divider that worked out quite well😛icture 2.

b 🙂

 

[Scruffyht]

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,

Hi Oliver ... Can I make the width 24" instead of 24.644? will make it easier to get cut from a 49" sheet of MDF ... also when you say the port can be pushed to the end of the duct in the corner are you referring to in front of the speaker at the bottom of the box?

Thanks

Steve

 

[Scruffyht]

Hi Steve,

Have a look at Picture 1. Are you aware of the frame Width of the drivers ( 15” 5/16): You have to 'DIY' decide on if to use a slanted baffle and provide the actual drawing dimensions at S2 and S3.

FYI.A couple of years ago I designed a small piggy-back T-TQWT with a slanted divider that worked out quite well😛icture 2.

b 🙂

Hi Bjorno ... thanks for the drawing ... Is this for a single SDX15? as I only own one of those drivers and they have not started building the MK II yet afaik ... been in design for about 2 years so we wont know the parameters till then ... I was going to use the |TC sounds LMS-R15 for the other box ... I do know about the frame dimensions but the driver was going to be installed on the front of the ported box ... each box dimension was 48X43.75X16 with a 3" wide and 40" long slot port

Having said that the dimensions on a ported box are simple in comparison to this and I am at a loss as to what angle to tilt the driver 😕

feel bad that you have to hold my hand on this but the performance increase is too tempting not to consider

 

[tb46]

Hi Scruffyht,

Post #43: "...Can I make the width 24" instead of 24.644? will make it easier to get cut from a 49" sheet of MDF...also when you say the port can be pushed to the end of the duct in the corner are you referring to in front of the speaker at the bottom of the box?"

How about inserting the bottom of the box (when installed in your riser), that would make it 23.204"x60.89", and the top of the box 24.644"x60.89" (unchanged). That would give you some extra wiggle room. You have to make the respective adjustments in the width of the narrow boards. I think it would be preferable to stay with the design dimensions, even though, these enclosures seem to be very forgiving, as you can fine tune with the fill.

I'll attach a quick sketch that may clarify the port location(s).

Regards,

 

[Scruffyht]

Thanks Oliver ... confused on the dimensions as it sounds like it would not be square?? so I will just go with your original dimensions 🙂

As to your reference on tuning ... are you referring to REW?

Thanks again

Steve

 

[tb46]

Hi Scruffyht,

Another sketch to clarify the dimensions, hope that helps; let me know if there is any other question.

As to tuning: for starters stay with the amount of fill as recommended by bjorno. Once the subs are in place you can still make adjustments. REW sounds like a good choice for room measurements. Listening, particularly in the cross-over range is always important. The most important point to keep in mind is that you need access to the stuffing (and the drivers 🙂).

Regards,

 

[Scruffyht]

Hi Oliver ... I am about to order the drivers but just wondered if you had modeled a similar enclosure with a driver other than the W8Q-1071F?

Is there another driver you would recommend that would outperform this one?

 

[tb46]

Hi Scruffyht,

Not with this enclosure height limitation (10"). Maybe bjorno has run into one?

Regards,

 

[Scruffyht]

So Solen (cdn dist) only have one left in stock ... what about this one? ... Tang Band W69-1042J 6"x9" Subwoofer 264-837

 

[BP1Fanatic]

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🙂

I'm surprised that most people using HR don't do this.

 

[Scruffyht]

So I ordered the last one from Solen ... the lady that answered the phone said they dont expect to get any more ... Oliver ... can you please post the drawing for the single you did for permo but with a slot port? ... I will use that to replace a sub I have in another room if I cant get ahold of 3 more drivers ... if anyone has 3 of these drivers for sale please let me know ... otherwise I would be open to suggestions on a alternate driver

 

[Scruffyht]

Hey Oliver ... what about the JBL GTO1214 you mentioned earlier in the thread?

 

[Scruffyht]

Or this one? ... http://www.creativesound.ca/pdf/CSS-SDX10-data-140408.pdf

 

[tb46]

Hi Scruffyht,

See permo's thread, Post #177 for the "Single W8Q-1071D" drawing. It has a slot port, the circular port is the "alternate".

As to the W69-1042J 6"x9", it would work well in a smaller enclosure, but has nowhere near the displacement of the 8"x12". It is currently for sale @ PE, maybe a Quad instead of a Dual?

The GTO1214 does not fit your form factor of 10" external box height (at least not easily). I did a dual driver T-TQWT version of this (with bjorno's help) for reminence here on diyaudio. You could re-arrange that design to fit your space (expect for the 10" dimension).

The CSS SDX10 would work, but again it calls for more than 10" external height.

I'd keep on looking for the 8"x12" as a first choice.

Regards,

 

[Scruffyht]

Hi Oliver,

Thanks for the reply ... How tall a cabinet would we need to accomodate the CSS SDX10? ... 1 in each box

 

[tb46]

Hi Scruffyht,

" ... How tall a cabinet would we need to accomodate the CSS SDX10? ... 1 in each box..."

Are we still talking about venting into the room corners with the cabinet mounted in a riser? The minimum riser height would be about "driver diameter plus 1/8" plus 2 x material thickness". The other dimensions depend on the type of fold used. Luckily the SDX10 does well with the driver located near both ends of a even diameter pipe (T-QWP), that makes folding easier.

A Single SDX10 does not have the output of a dual 8"x12", but it makes for a much smaller enclosure; Hornresp indicates a V_net of about 75 L.

Regards,

 

[Scruffyht]

Hi Scruffyht,

" ... How tall a cabinet would we need to accomodate the CSS SDX10? ... 1 in each box..."

Are we still talking about venting into the room corners with the cabinet mounted in a riser? The minimum riser height would be about "driver diameter plus 1/8" plus 2 x material thickness". The other dimensions depend on the type of fold used. Luckily the SDX10 does well with the driver located near both ends of a even diameter pipe (T-QWP), that makes folding easier.

A Single SDX10 does not have the output of a dual 8"x12", but it makes for a much smaller enclosure; Hornresp indicates a V_net of about 75 L.

Regards,

Hi Oliver ... thats interesting that the dual TB have more output ... would dual SDX10's have more output than the TB?

so with dual SDX10 we are talking about a box just under 12" with 3/4" mdf venting into the corners?

Thanks again

Steve

 

[tb46]

Hi Scruffyht,

Post #57:"...driver located at both ends of a even diameter pipe..."

That was an oversight, the driver is located only at one end of the pipe, the rest is correct; anyway the Hornresp Input tells the story (long L12, short L34).

For a dual driver with a straight pipe the cross-sectional areas don't quite double (from single 190cm^2 to dual 330cm^2), and the lengths change slightly (to improve the 0.5 x Pi SPL response in Hornresp). Obviously, we can double the input power.

Both version stay slightly below Xmax (=18.4mm) @ nominal input power of 150W for the single, and 300 W for the dual. This is a plus, as these drivers have been reported not to like to driven past Xmax.

As to riser height: 10.8125 (SDX10 Dia.) plus 1.5 (2xMDF) plus 0.125 (wiggle room) equals 12.4375". To get lower you have to tilt the drivers; same problem as with the SDX15s and 16".

Well, back to work......

REgards,

 

[Scruffyht]

Hi Oliver ... I know you did alot of work on the last box and then only one driver was available 😱 ... but could you please do the box dimensions for me for the dual SDX10?

Thanks

Steve