Introducing: The Pit Vipers (Ooh Yeah!!!)

[djg]

Here's a link to a Troels SBA 8" 4" dome tweeter 3 way speaker, significantly smaller than the Viper, with some good construction pictures.

http://www.troelsgravesen.dk/SBAcoustics-3WC.htm

[9sheng]

I was looking for 6" PVC pipe caps and found some differences.


No.1 As shown in the picture above, the pipe cap of model DN150 has an inner diameter of 160.7mm, an outer diameter of 184.5mm, the height of L1 is 86.5mm, and the height of L2 is 125.9mm. It will have a spherical bump at the top. So his total height is 125.9mm.
I looked at paul's photo and it looks like he has bumps too.



No.2 I saw the cap numbered 6P06 from Amazon, his total height is only about 80mm.
this is the connection

https://www.amazon.com/NDS-6P06-Solvent-Fitting-6-Inch/dp/B00L4AO506/ref=sr_1_2?keywords=6+pvc+cap&qid=1657344569&sr=8-2

No.3 I also found another specification of the cap, their inner diameter is 160mm, but their height is different. Below is the connection

https://www.plasticpipeshop.co.uk/6-Plain-PVC-End-Cap_p_716.html

I know that the size of the interior space formed by different heights is different, so I need you to help me determine which model. Or in small differences, there will be no effect on the sound? Can I choose No.1 first?

As long as the diameter is 160mm, whether it is a raised hat or a flat hat, the same internal space can be achieved at a certain height. But if you choose a flat hat, how much height do you need?

[djg]

You would want it big enough for the speaker to fit inside.

[Paul Carmody]

I used the ones with the flat bottom that you show in the Amazon picture.

[Serenitynow]

I've been wondering about the internal volume for the midranges as well.

I don't think ( I could be wrong however ) that it really matters unless the driver is playing close to fs. I can't remember the specs right off hand, but I don't think Paul has them playing that low in this design.

Someone more knowledgeable will hopefully settle our confusion about this.

Just checked.
Fs of the mid is about 52 Hz. Looks like they're being crossed at around 450 Hz. I don't THINK the size of the enclosure for them will matter in this case.

[9sheng]

Paul Carmody It took me some time to make a structural diagram of the enclosure. I made some changes to the internal bracket. I used two pieces of wood with a width of 36mm to connect the back, lock a screw + glue, and it should be very strong. I adjusted the internal horizontal brackets to the upper and lower edges of the subwoofer. I think the subwoofer will bring more vibration, so I installed the brackets closer to the subwoofer.
Due to the height of the PVC cap of the midrange speaker, it may touch the vertical bracket wooden bar. We can adjust the position forward and backward by adjusting the 36mm wide wooden bar connection points on the left and right sides. I also added 2 wooden strips on the left and right sides of the back baffle for glue sticking, which should help strengthen the overall back panel.
I adjusted inches to millimeters. The overall cabinet structure is obtained.
I upload 3D source file, please help me to check, is the size correct?
And is my internal support structure reasonable?
Thanks!




Pit Vipers 3D (SketchUp 2019) File Download

https://drive.google.com/file/d/1STuLDP66emaUou6CnAbo6M8y42ZowD5s/view?usp=sharing

[Paul Carmody]

Were you planning on doing a removable baffle?

[9sheng]

Yes. The baffle is a single piece, I may use 18mm mdf board + 2mm solid wood board to stick together, so that the surface will look more textured. Secure it with numerous screws around the panel.

In fact, I am still indecisive at the moment, and have not yet finalized whether to use a detachable panel. A lot of screws on the panel will also not look so good.

I saw the forum post last night and I was wondering if it would be better to improve another kind of internal support.
Quoting images from the forum



I ordered the speakers from soundimports and they have arrived in my locker after 108,000 miles and he is looking forward to my construction as soon as possible.

[Serenitynow]

I just noticed the 5.0 mH Iron Core inductor is showing up as IN STOCK on PEs website

[djg]

What happened?

[Serenitynow]

The boss had other plans that intervened.

[Chris Roemer]

That's an AWFUL lot of stuffing (maybe too much?).

[DrewsBrews]

Regarding adhesion of the pvc cap.. I wonder if a shallow rabbit on the back of the motor board, where the cap would slip into, might be beneficial to give more surface area to adhere to. Would probably be easiest to do before the driver hole is cut though otherwise you lose the material for the circle cutting jig to center on. Would reduce the internal volume of the camber a bit too.

[Paul Carmody]

Regarding adhesion of the pvc cap.. I wonder if a shallow rabbit on the back of the motor board, where the cap would slip into, might be beneficial to give more surface area to adhere to. Would probably be easiest to do before the driver hole is cut though otherwise you lose the material for the circle cutting jig to center on. Would reduce the internal volume of the camber a bit too.

Yes, I had definitely thought of that, and would highly recommend it to anyone building this. It just makes for a more refined fit-and-finish. I will say from experience that when you need to flip a piece over when routing holes, it does take some pre-planning, though. (ie: you run the risk of losing your pivot hole if you route all the way though)

Honestly, sometimes when I do my prototypes I skip some of the "fit and finish" details. Sometimes it's just simply to save time, but other times I do it to prove that "you can still have great-sounding speakers even if you're not a perfectionist woodworker." If someone wants to build my design, I really don't want them to feel intimidated or held-back because they don't have certain tools or skills.

[Serenitynow]

Well....
I have had a chance to design, layout and program all of the parts for the enclosures for these.

[Serenitynow]

[Serenitynow]

[Serenitynow]

[Serenitynow]