Tweeter selection
So, I was thinking about the tweeter. We don't really need to decide the tweeter yet. I have the SB26STAC, SB26ADC and SB26STWG on hand and can decide when the cabinet is built and the SLS 830669 comes back into stock at PE. I also don't mind buying the Peerless tweeter if we go in that direction.
We did need to decide the woofer, because it determines the cabinet size and impacted the midrange. And we needed to determine the midrange because it impacts the tweeter. But at this point, the tweeter decision can wait.
Cabinet size
I have been thinking we should determine the cabinet size next. This will give me a chance to maybe get it complete by mid-May when the SLS 830669 is supposed to be back in stock. But, because there is some uncertainty regarding the T/S Parameters, there is an argument to just wait until they are back in stock and take actual measurements.
The problem right now is that PE and Soundimports have data sheets from 2017 that suggest the SLS 12" models good enough in 2.2 cf (62 L) Qtc = 0.90.
But Peerless has an updated data sheet on its webpage from 2021 that suggests in 2.2 cf that Qtc = 1.0 while in 2.7 cf (76 L) Qtc = 0.95.
The JBL L100 is (in inches) 25.5 (H) x 15.5 (W) x 14.5 (D) providing 2.5 cf. Assuming 0.30 cf for midrange enclosure and bracing gets us to 2.2 cf.
A little bigger, at 27 (H) x 16.5 (W) x 15 (D) provides 3.0cf gross and 2.70 cf after midrange enclosure and bracing.
This is a little bigger than the JBL L100 in each dimension and a little smaller than the SB Acoustics Gemma kit in each dimension.
@WeirdBeard will post some mockups to visualize the different sizes.
Do we make a decision now - either the JBL L100 size, the size proposed above, or something different (even bigger?)? And I start construction in the next few weeks. Or, do we wait for the driver to be in stock and take actual T/S measurements and go from there?
So, I was thinking about the tweeter. We don't really need to decide the tweeter yet. I have the SB26STAC, SB26ADC and SB26STWG on hand and can decide when the cabinet is built and the SLS 830669 comes back into stock at PE. I also don't mind buying the Peerless tweeter if we go in that direction.
We did need to decide the woofer, because it determines the cabinet size and impacted the midrange. And we needed to determine the midrange because it impacts the tweeter. But at this point, the tweeter decision can wait.
Cabinet size
I have been thinking we should determine the cabinet size next. This will give me a chance to maybe get it complete by mid-May when the SLS 830669 is supposed to be back in stock. But, because there is some uncertainty regarding the T/S Parameters, there is an argument to just wait until they are back in stock and take actual measurements.
The problem right now is that PE and Soundimports have data sheets from 2017 that suggest the SLS 12" models good enough in 2.2 cf (62 L) Qtc = 0.90.
But Peerless has an updated data sheet on its webpage from 2021 that suggests in 2.2 cf that Qtc = 1.0 while in 2.7 cf (76 L) Qtc = 0.95.
The JBL L100 is (in inches) 25.5 (H) x 15.5 (W) x 14.5 (D) providing 2.5 cf. Assuming 0.30 cf for midrange enclosure and bracing gets us to 2.2 cf.
A little bigger, at 27 (H) x 16.5 (W) x 15 (D) provides 3.0cf gross and 2.70 cf after midrange enclosure and bracing.
This is a little bigger than the JBL L100 in each dimension and a little smaller than the SB Acoustics Gemma kit in each dimension.
@WeirdBeard will post some mockups to visualize the different sizes.
Do we make a decision now - either the JBL L100 size, the size proposed above, or something different (even bigger?)? And I start construction in the next few weeks. Or, do we wait for the driver to be in stock and take actual T/S measurements and go from there?
Hello everyone!
These are the mock ups @A4eaudio was talking about. I left the sides of the enclosures white because they 're easier to stand out. Dark colors make it difficult for the sizes to be distinguished. These are rough previews and they will get refined as we proceed. If anyone needs additional info or photos, feel free to message me. Cheers!
These are the mock ups @A4eaudio was talking about. I left the sides of the enclosures white because they 're easier to stand out. Dark colors make it difficult for the sizes to be distinguished. These are rough previews and they will get refined as we proceed. If anyone needs additional info or photos, feel free to message me. Cheers!
Attachments
Can we do some modeling and look at the curves with the shortlisted driver and see how we end up on F3, F6 and F10 with different cabinet sizes (just for example 62 liters, 70 liters, 76 liters etc.)? Maybe can start with the published data (manufacturer or 3rd party)?
Hopefully we are nearly there with the cabinet dimensions, and now it's a matter of fine tuning.
There a 25% discount at PE at the moment…
My minor concern with the 830669 is the rough response at the top end might need an electrical LR4 which means an additional cap (increased cost)
Agree with @A4eaudio that decision on tweeter doesn’t need to be made. The flat faced tweeter may be a little cheaper, but may need more parts.
real measurements will tell
My minor concern with the 830669 is the rough response at the top end might need an electrical LR4 which means an additional cap (increased cost)
Agree with @A4eaudio that decision on tweeter doesn’t need to be made. The flat faced tweeter may be a little cheaper, but may need more parts.
real measurements will tell
I am hoping to edit post #1 soon with some Design Goals, key posts, and our decision points. Not sure when "soon" will be.
But see posts #260, 277, 297, 411 and 413 (hopefully I have those right).
So too many posts to read to effectively catch up
Where are you at as to woofer and format?……still monkey coffin with Peerless SLS 830669 ?
16” wide baffle ?…….or 18” to offset BSC?
Where are you at as to woofer and format?……still monkey coffin with Peerless SLS 830669 ?
16” wide baffle ?…….or 18” to offset BSC?
Yeah, but only for some clearance products.
The PE Speaker Design Competition is August 1st, and participants get 20% off everything, but I don't think I will wait until August 1st to save the money. I will, however, probably wait until Memorial Day or look for a 10% off Coupon Code once they are in stock
Woofer is Peerless 830669.
Midrange is Scanspeak 15W/4434G00
Tweeter to be determined later - either SB26STAC, SB26ADC, SB26STWG or Peerless H26TG45-06 (or corresponding Scanspeak Discovery twin)
Yes, Monkey Coffin
Current question is what size. Potentially 27 (H) x 16.5 (W) x 15 (D) , but see the posts right above on this page #1,162 and #1,163.
16.5" wide as A4eaudio has stated in post # 1162 is already pushing it in terms of width and visual impact (IMHO).
A4eaudio,
Thanks for sharing the posts with modelling data. Please correct me if I am wrong - we are ok with settling on a sealed design?
Looks like now the way forward is buy the actual drivers and measure...
@zman01 - yes, I have the midranges and tweeters and have measurements. I'll try to get the at first post updated with key posts. [I will retake all measurements in the real cabinet when the woofers are in.]
The woofer is not in stock in the US until the beginning of May. A lot of Peerless drivers that were no longer available (NLA) for the last few years are on their way to Parts Express on the slow boat from China.
The woofer is not in stock in the US until the beginning of May. A lot of Peerless drivers that were no longer available (NLA) for the last few years are on their way to Parts Express on the slow boat from China.
Aaaagh….ok…..thanks for the update
so it’s been a LONG time since I’ve worked with that subwoofer but back when these for $50……pre 2010 we made quite a few of these using 2 in parallel isobaric in 2cuft ported and tuned to 30hz……2nd order HD was reduced along with cabinet size…..while designed primarily as subs, when run up to 300hz the midbass slam was amazingly tight due to the simple shorting ring design working with the Isobarik system…….not sure if your budget allows for 2 per box though……..SQ wise?…..the performance value is huge.
Perfect for a B3 alignment with a big cap in circuit with the woofer. Dual purpose: some DC and LF protection and nicer low extension. When I find time, I’ll throw it in a sim, but beat me to that if you like.
Today or next week? Perhaps there needs to be a US version and a rest of the world version? Mind you some drivers have always been significantly cheaper in US than here in Europe. Other areas of the world have it even worse in terms of both price and availability. Avoiding drivers that are only available to DIYers in one area of the world (i.e. don't have a MOQ) or have been discontinued is reasonable. Seeking drivers that are universally very high value for money likely isn't.
Peerless 12" SLS are $209 here. Postage is a common issue, whether we order overseas or buy an overseas product locally.
Peerless Datasheet / Dibirama - blue ovl
Closed box 70L full stuffed
Qtc = 0.75, F3 = 48Hz / Qtc = 0.77, F3 = 45Hz (Dibirama)
Baffle 40x65, W coordinates 20, 16cm from bottom
Box dimensions including 8L for mid enclosure, braces, etc.
Closed box 70L full stuffed
Qtc = 0.75, F3 = 48Hz / Qtc = 0.77, F3 = 45Hz (Dibirama)
Baffle 40x65, W coordinates 20, 16cm from bottom
Box dimensions including 8L for mid enclosure, braces, etc.
yeah i thought that might blow the budget with the SS mid driver being settled on. The box volume you're lookin at will work with the VAS of one and the efficiency of one at 8 ohms isn't a power soak,......good choice
Compound driver solutions have become obsolete for a good reason. Any electronic correction, DSP or analog LT, is way cheaper and just as effective.