Jims 3 way speaker build

[Chris Roemer]

Your brace holes are fine ...

but, the easiest and most efficient way to brace a box is using 1" (or 3/4") dowels (or square stock) from wall to wall.

[jimbones]

I thought tying in all 4 sides would be very efficient as I can brace the front and rear baffle at the same time together with the sides.

[a4eaudio]

Normally the dowels or scrap braces are at least easier, but with your angled walls due to the trapezoid, this might be easier anyways.

[jimbones]

This is the midrange enclosure mounted to the baffle.

[a4eaudio]

You might want/need to chamfer the backside of the midrange opening.

[jimbones]

a4eaudio, the midrange is rear mounted.

[a4eaudio]

Oh yeah! I remember now.

[satx]

I just found your build tread here and read through it with interest. I’ve been thinking lately of a slim three way using some similar drivers. The AC130F1 (2) which I’ve used before and like a lot, a number of woofer choices (side mounted) including the SB34SWNRX-75, for the smaller sealed enclosure than the brute you’re using and likely the Scanspeak 9130 because I have them on hand.

Anyways, I didn’t see it mentioned by anyone, but do you have any concern about the midrange sensitivity keeping up with your woofer? When you had the woofer mounted higher I thought it could be a little close, but now that you’ve moved it near the floor, you might not loose much, or anything to baffle step. Just a thought.

Also my experience has been that I do myself a big favor by making a test baffle for the M/T and measuring as I add pieces of wood or cardboard the the edges to find the best locations regarding diffraction. It’s always temping to design the look first and then try to hammer the response to fit, but It can save a lot of headache during crossover design and just make for a better sounding finished product.

PS can you link to your thread about driver selection? For some reason I can’t find it.​ Thanks

[jimbones]

I just found your build tread here and read through it with interest. I’ve been thinking lately of a slim three way using some similar drivers. The AC130F1 (2) which I’ve used before and like a lot, a number of woofer choices (side mounted) including the SB34SWNRX-75, for the smaller sealed enclosure than the brute you’re using and likely the Scanspeak 9130 because I have them on hand.

Anyways, I didn’t see it mentioned by anyone, but do you have any concern about the midrange sensitivity keeping up with your woofer? <<it is 2 db lower sensitivity but not really. i find that in a 3way you can hav a slightly lower sensitivity mid and I like a more recessed sound.>> When you had the woofer mounted higher I thought it could be a little close, but now that you’ve moved it near the floor, you might not loose much, or anything to baffle step. Just a thought.

Also my experience has been that I do myself a big favor by making a test baffle for the M/T and measuring as I add pieces of wood or cardboard the the edges to find the best locations regarding diffraction. It’s always temping to design the look first and then try to hammer the response to fit, but It can save a lot of headache during crossover design and just make for a better sounding finished product. << I agree but everyone said that the test baffle should be exactly like the final baffle so I figured, if I am going through the trouble to build something that close......>>

PS can you link to your thread about driver selection? For some reason I can’t find it.​ Thanks

<< Give me a day I'll add the link, fabricating today >>

[satx]

Yes, you can usually expect 1-2db of bandpass gain depending on where you crossover, but your mid is less sensitive than spec’d. You can’t trust AC’s published specs unfortunately. Zach has it at about 86 and my experience roughly matches this.

Not sure what you mean about the test baffle, but if it’s working for you then that’s all that matters! Have fun making saw dust!

[jimbones]

here is the link satx https://www.diyaudio.com/community/t.../#post-7117504 https://www.diyaudio.com/community/t...drange.386265/

[satx]

Ah, thanks. That’s why I couldn’t find it…it’s not on PE!

[satx]

I didn’t know how to add a photo to my comment. This is from Zach’s testing of the AC130F1

[jimbones]

I didn’t know how to add a photo to my comment. This is from Zach’s testing of the AC130F1

UGGHHH. I didnt see that. I was using AC's spec of 89 db. If you look at their published graph it seems higher for sure. Well the good thing is there are a lot of 5 inch drivers to choose from NO??

[PWR RYD]

If you're OK using a 4 ohm, 5" for the mid the SB15CAC30-04 performance looks great and has a sensitivity of 88 dB. I've used its 8 ohm brother and it sounds fantastic. Madisound has them in stock and while they aren't cheap they aren't stupid expensive either. Just another alternative to consider.

[satx]

UGGHHH. I didnt see that. I was using AC's spec of 89 db. If you look at their published graph it seems higher for sure. Well the good thing is there are a lot of 5 inch drivers to choose from NO??

Having used the AC130, I’d try to still use it if you can. It really is a great little driver. Plus you already bought it.

Two possibilities:
flip your woofer and port, so you aren’t getting as much floor gain.
Use two mids in and MTM.
Or hell, maybe you’ll be fine. Even near the ground, I feel like you lose some sensitivity. Also, you could try a few tricks like using a small guage inductor with a high R value, tune lower for a shelved bass response or maybe even seal the port.
Also, depending on where you cross the woofer and the slope, you may need a notch for the upper impedance peak and can use that to reduce the level some

[satx]

If you wanted to step it up a bit, I’ve used the Satori 5” mid with really good results. The price has gone up, of course, but it’s still a decent deal compared to other high end drivers.
i think the AC driver compares favorably though. Even with the higher distortion. Or maybe because of it? Who knows, but it sounds very nice and looks good to boot

[jimbones]

satx Ive used Satori before (MW16P) so I am looking for a different sound so thats why I picked the AC. I really hope it works out. What if I lower the XO point lower (from anticipated 330hz to 250 hz)? Will that help?

[satx]

I’d think that raising it would help boost the mid more, but it’s hard to know exactly what will work until you measure and sim.
Btw, if you measure from 1m, the level of the woofer is probably going to appear lower than expected due to the extra distance to the mic

[rpb]

How close to the back, and side walls will the speakers be used?

The midrange portion of the xo can be designed with a couple dB of gain. Try running some sims, or better yet, measurements on the mid with a xo connected.

[jimbones]

How close to the back, and side walls will the speakers be used?

The midrange portion of the xo can be designed with a couple dB of gain. Try running some sims, or better yet, measurements on the mid with a xo connected.

rpb the speakers will be about 3 ft from side walls and 5 feet from rear wall. The room is 14 by 22.

[jimbones]

Hi Everyone. Im still here. Im making progress albeit slowly. Today I going to prime paint as much as I can get done today, I expect at least the front baffles and rear panels and maybe the cabinets. I'll post pics as soon as I have some measurable progress, Stay tuned...

[jimbones]

Ok so I applied 2 coats of Zinnser primer going to let that dry overnight then top coat with black. I still have the other cabinet to prime yet.