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JBL L82/L100-inspired bookshelves

Reigningchamp

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Apr 25, 2020
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I recently fell in love with the walnut veneer and burnt orange quadrex foam grilled of the (new) JBL L82/L100. I also found out that you can purchase the grilles, or a fairly good clone of the foam, for a reasonable amount of money. So, I’m looking to make something in the same dimensions as the L82, but with a fun twist - I want it to be a 3-way and I want a bigger woofer. Does anyone have any opinions/comments on mating a 4-inch coaxial with a 10-inch woofer? They would be in roughly the same layout as the existing driver. The cabinet depth could be increased, port could be changed, etc. On a quick first pass of driver selection I found for woofers: Dayton Audio RS270P, Sbacoustics SB29NRX75, Scan-speak 26W/8534G. For coaxials: Sbacoustics SB12PFCR25, Dayton CX120, and maybe a KEF uni-Q from here. These would stand alone with no sub and would be placed in a small room of approximately 200 sq ft, so I would be aiming for extension to ~40 hz.
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gy-k

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Oct 25, 2021
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If I have the dimensions of the L82 right, I'd estimate the cabinet's net volume to be around 27l. You'd need more of a subwoofer type 10" with lower Vas than those you've listed. and also low Fs. Like the subwoofer version of the SB29: SB29SWNRX or the Peerless XLS-P830452. It seems to me right now based on the TS parameters that the Peerless XLS would be preferable.

The Q300 driver you've linked is a larger 6" cone Kef coaxial driver while the other two are 4". Isn't the Kef driver in the Diya thread also a 4"? There's a 5" coaxial from Sica, with a nice paper cone, I know someone who has an unused/open box pair for sale (EU). Based on the TS parameters the sensitivity of the Sica and Peerles are like within 0.6dB, maybe useful.
 
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Reigningchamp

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If I have the dimensions of the L82 right, I'd estimate the cabinet's net volume to be around 27l. You'd need more of a subwoofer type 10" with lower Vas than those you've listed. and also low Fs. Like the subwoofer version of the SB29: SB29SWNRX or the Peerless XLS-P830452. It seems to me right now based on the TS parameters that the Peerless XLS would be preferable.

The Q300 driver you've linked is a larger 6" cone Kef coaxial driver while the other two are 4". Isn't the Kef driver in the Diya thread also a 4"? There's a 5" coaxial from Sica, with a nice paper cone, I know someone who has an unused/open box pair for sale (EU). Based on the TS parameters the sensitivity of the Sica and Peerles are like within 0.6dB, maybe useful.
Thanks for the recommendation, I’ll take a serious look at that Peerless XLS. I was actually looking to use the 5” midrange used in the R3 instead, I think it would fit the use case much better.

I am really doubting my idea here given that I’ve never seen a coax crossed to a subwoofer. That sounds wrong to me, but given the frequency responses I don’t see why it should be a problem. Is this a fool’s errand?
 

ROOSKIE

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Feb 27, 2020
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Thanks for the recommendation, I’ll take a serious look at that Peerless XLS. I was actually looking to use the 5” midrange used in the R3 instead, I think it would fit the use case much better.

I am really doubting my idea here given that I’ve never seen a coax crossed to a subwoofer. That sounds wrong to me, but given the frequency responses I don’t see why it should be a problem. Is this a fool’s errand?
There is no reason you can't cross a coax to a large woofer.
It is not that much different from a non-coax. The main thing to keep excursions down from the mid so the waveguide it serves as for the tweeter doesn't change a lot. (like no 12mm each way excursions yah know?)

I DIY and you have to start somewhere but if this is where you are starting you likely need a lot of help or be cool with a final design that would not measure well. (unless you get very lucky)
Is this because you want to DIY or save $$?
The L82's can be had for under $2k and B-stock for $1500. Plan to spend way more than that effectively in time designing and making your speaker that you can not return if it doesn't sound good to you. I think the KEF coax's are hard to get and do cost some coin by the way.
Tang Band has a couple cool ones at PE. Pricy as well.

FWIIW the woofer the L82 is superb, a real nice one. A lot of 10's are not going perform as well and while it would be cool maybe to have a midrange between an 8 and a 1" the L82 has pretty good directivity and darn if it doesn't sound excellent. Maybe buy a set and use them as a reference for your design and if the final project is great sell the L82's.
 
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