Site Links
Howdy, Stranger!
It looks like you're new here. If you want to get involved, click one of these buttons!
Quick Links
Categories
Winter project 1
This will be a TMM using the SB Acoustics poly 5" 8 ohm and the Hiquphon OW1.
All modeling done at 28 watts(!), two ways. One wide open model and one with a 40Hz highpass. The wide open version should handle the vast majority of music with absolutely no issues due to the very low F3 of 36Hz and the net Xmax of 11mm.
Excursion at 28 watts sans high pass:
SPL without taking baffle step losses into consideration:
Extension with high pass enabled. This is how they would be used in my basement, for example:
Excursion with said high pass:
In both cases with a 3" port, port velocity is comfortably under 20M/S.
These may also be done as a MLTL, who knows.
Anyways, here is what I am seeing for the basic baffle shape:
Up next will be working through CAD to create design files for the CNC table. I made the baffle quite big for a typical 1.25 cubic foot cabinet to make plenty of allowance for internal bracing and 1.5: baffle thickness.
This should qualify as borderline high-end, I imagine. Plenty of thermal and mechanical power handling, low distortion, and with the facets and some smart crossover work will have great on and off-axis response.
With any luck not only will I be able to host DakotaDIY this summer I should also have this done and ready to show - along with the Rival/TL design.
Stay warm, brothers.
Comments
FYI, this sim was made with measured parameters - which were far enough off of advertised as to initially be frustrating modeling a bookshelf. Hopefully the second pair I am about to order (on sale at Mad for $48) will be consistent with these.
What is the model number of the SB woofer you are working-on or did I miss it?
https://www.madisoundspeakerstore.com/approx-5-woofers/sb-acoustics-sb15mfc30-8-5-poly-cone-woofer/
Specs don't match JR's description at the ^ link . . . (Xmax & Fs are off)
Probably why JR said above..."FYI, this sim was made with measured parameters - which were far enough off of advertised as to initially be frustrating..."
JR used measured parameters for this model.
Good catch! Thanks.
Nice idea, I like the concept of a high pass filter on a woofer. It will be interesting if you plan to do any distortion measurements.
It would take some work setting up the HT signal chain to take the measurements but I suppose it could be done. A passive 40Hz high pass is a tricky dick to pull.
Just ordered the other two woofers. I am going to measure all four and see if I measured an outlier or what. I mean, I like how it modeled as a pair in a tower - but it just bothered me that SB was that far off. They are usually like Dayton - spot on to advertised.
I agree. All the SB drivers I have bought have been spot on. Better than Dayton and Peerless actually.
JR, what happened to this project? I know you are using OW1's with your "something nicer" build with the NRX2 paper cone drivers so wondering if you abandoned this. In particular was wondering what you though of the sound of the poly-cones, if you got that far.
Still on my radar. Finishing g the TM up first, and then think about starting this build.