Box & Winisd for JL Audio 13.5 W7

[pjoseph]

I wanted to see if the Winisd graphs shown below look correct? The blue line is based on WinIsd box volume and the yellow is based on a smaller sized box. Reading on other forums it seems like for this driver a smaller box around 1.8 to 2. cu ft is recommended.
I plan to add two 13.5 W7's in the near future in their own sealed box and power them using ep2500 along with DCX 2496.

Any issues/problems going with 2.0cu ft sealed box not including the driver or bracing?

 

[annunaki]

I would have to model it myself. 2.0ft^3 is small for the 13 if memory serves me correctly.

I want to say that 3.0ft^3 was about right in a sealed application. You can add ep to lower the effective f3 also do to the extremely low power compression and linearity.

I would model one vented and then find two 15” passive radiators to meet the vented model.

 

[pjoseph]

Annunaki, i am going to go with Qty (1) 12W7AE to start instead of the 13W7 with that said i am hoping to get started over the holiday break. Should i shoot for 2.17cuft which i found in an old post by you when you built a box for your 12W7?

 

[TLS Guy]

The Qts is plenty generous. With the driver having a Qt below 0.5 (just) you should be able to drop total system Qts below 0.7. I think that sub will be over warm as modeled.

 

[lovinthehd]

The Qts is plenty generous. With the driver having a Qt below 0.5 (just) you should be able to drop total system Qts below 0.7. I think that sub will be over warm as modeled.

What does "over warm" translate to?

 

[TLS Guy]

What does "over warm" translate to?

Actually it is closer to 0.8 being 0.75. I know that sounds like a small increase but it is significant.

Most people consider the optimal total system Qts being 0.5. Below 0.5 things start sounding over dry and lacking in body. At 0.7 cellos double bases and tymps start to just sound a little tubby and unnatural. Over 0.7 then things start progressing to frankly boomy.

Most systems in my view have total Qts higher than desirable. This also adversely interacts with room modes.

I aim for 0.5 and stick pretty close to it. That is why I really favor TL loading. My Eagan system has a Qts of 0.7 in the sub bass system and the bass spreads around a little compared to here.

If you go to a concert try and remember what the bass string section and tympani really sound like. They are really taught, and quite unlike far too many speakers.

 

[lovinthehd]

Actually it is closer to 0.8 being 0.75. I know that sounds like a small increase but it is significant.

Most people consider the optimal total system Qts being 0.5. Below 0.5 things start sounding over dry and lacking in body. At 0.7 cellos double bases and tymps start to just sound a little tubby and unnatural. Over 0.7 then things start progressing to frankly boomy.

Most systems in my view have total Qts higher than desirable. This also adversely interacts with room modes.

I aim for 0.5 and stick pretty close to it. That is why I really favor TL loading. My Eagan system has a Qts of 0.7 in the sub bass system and the bass spreads around a little compared to here.

If you go to a concert try and remember what the bass string section and tympani really sound like. They are really taught, and quite unlike far too many speakers.

What about other types of music? Double basses and tympani mean little to me...

 

[TLS Guy]

What about other types of music? Double basses and tympani mean little to me...

OK boomy drum set and bloated bass guitar and male voices.

 

[pjoseph]

TLS,
the graph in my original post is for a 13W7, the one below is for a 12W7, i did not change any parameters in winisd.

 

[TLS Guy]

TLS,
the graph in my original post is for a 13W7, the one below is for a 12W7, i did not change any parameters in winisd.
View attachment 27379

Well there is a curve but no data for the 12 W7.

If you look at the 13 W7 data total. system Q is dropping as you increase enclosure size. The larger enclosure is getting close, but it need to be a bit bigger. You want to drop total system Q below 0.7 if you can.

You can not just go by the FR curve alone.

 

[pjoseph]

my mistake, see below i adjusted the volume on the second one to get it below .7

 

[TLS Guy]

That should be fine. You will need Eq, boosting 12 db per octave starting at 50 Hz. The Fs of that driver is 27 Hz, so you will need a high pass filter 12 db per octave at 25 Hz.

 

[pjoseph]

Thanks for the reply,
any harm going up to around 3.0 cu ft? reason why i ask is i came across a pre-cut 3.0 cu ft box at parts express which would save me the trouble of trying to find a local place to cut the wood for me since i do not have the tools to make the straight cuts required. I have no problem adding extra bracing and or modifying the existing bracing if needed,.
winisd graph based on 3.0 is below as well as link to box thanks again
https://www.parts-express.com/denovo-audio-knock-down-mdf-30-cu-ft-cubic-foot-subwoofer-cabinet--300-7087

 

[TLS Guy]

Thanks for the reply,
any harm going up to around 3.0 cu ft? reason why i ask is i came across a pre-cut 3.0 cu ft box at parts express which would save me the trouble of trying to find a local place to cut the wood for me since i do not have the tools to make the straight cuts required. I have no problem adding extra bracing and or modifying the existing bracing if needed,.
winisd graph based on 3.0 is below as well as link to box thanks again
https://www.parts-express.com/denovo-audio-knock-down-mdf-30-cu-ft-cubic-foot-subwoofer-cabinet--300-7087View attachment 27419View attachment 27419

That is even better. You have lowered Qtc to 0.664 now. That sub will sound a lot better then the first models. It will need the same Eq as above though.
It will not be a sub without the Eq.

 

[annunaki]

3.0ft^3 is completely fine on a 12W7 sealed. The PE knockdown enclosures are fine in that case. Get one without a mounting hole pre cut however. The cutout diameter on a W7 is non standard and smaller than normal 12” drivers.

 

[pjoseph]

Yup that is the one i got without the mounting hole.
Any thoughts on the bracing, not sure if more is needed. I plan to assemble the box with glue only, need to pick up a few more clamps.

 

[pjoseph]

Just wanted to follow up on my question above regarding the bracing, I would love to get started but want to make sure there is enough bracing first. Thanks again & Happy Holidays

 

[pjoseph]

got the sub and it just feels massive especially the foam surround.

 

[moves]

I would say that it is fine. I am using an 18" driver from Dayton and am using the same bracing but there are 2 cross braces instead of only 1.

What's the distance from the groove to the middle cross edge? Also, how deep is the groove for the Dado?

 

[pjoseph]

I added some measurements to the photo, if needed I thought i could get a piece of 3/4" mdf and cut off the four corners and curve the inside using a jig saw and place one in each corner. Each one would fit between the two existing braces in the middle of each panel, i tried to show this with the blue lines i added. Thanks again