Currently designing a bookshelf speaker with MA 7HD in sealed 9.5L chamber joined with a sealed woofer chamber (~7" wavecor) with woofer mounted on the side. Correct me if wrong, but a side-mounted woofer should ideally be limited to ~200hz max, so as not to have any potential voice content (in the 300-500hz range?) shooting sideways into nearby books.
I'm targeting a passive crossover and I've seen suggested that the natural rolloff in the sealed 7HD chamber is good enough to be left alone. This leaves just a crossover needed on the woofer itself, with low crossover in the 150-200 range being ideal, right? (Yes, I know components to achieve this are $$). Let me know if I'm thinking about the right way.
Thanks!
I'm targeting a passive crossover and I've seen suggested that the natural rolloff in the sealed 7HD chamber is good enough to be left alone. This leaves just a crossover needed on the woofer itself, with low crossover in the 150-200 range being ideal, right? (Yes, I know components to achieve this are $$). Let me know if I'm thinking about the right way.
Thanks!
Keep in mind that whem you add damping the apparent size of the sealed box will increase. You might want to shrink it a bit to maintain the butterworth Q.
The 7” Wavecore is the same as the CSS LDW7, which works decently vented. Probably in am ML-TL.
We went to balanced drivers on the side after finding difficulties getting just one sided woofer to work really well (using CSS SDX7, the precursor to the LDQ7.
2 woofers (in push-push) essentially give amnudirectional dispersion, were a lot easy to get to mesh. We did use smaller woofers (Silver Flute W14) which, as a generalization, should have better dispersion higher, and a 450 Hz passive XO.
With a passive XO you want woofers that are about 3dB more sensitive than the midTweeter to avoid having to pad down the top.
Passive XO parts are big, i am goung to get a basic miniDSP HD just to figure out where that passive XO works best. If you have another amp in the closet you can quickly and cheaply biamp with a PLLXO (some care needs to be taken in the speaker design to ensure 1st order works OK — not that hard)
dave
The 7” Wavecore is the same as the CSS LDW7, which works decently vented. Probably in am ML-TL.
We went to balanced drivers on the side after finding difficulties getting just one sided woofer to work really well (using CSS SDX7, the precursor to the LDQ7.
2 woofers (in push-push) essentially give amnudirectional dispersion, were a lot easy to get to mesh. We did use smaller woofers (Silver Flute W14) which, as a generalization, should have better dispersion higher, and a 450 Hz passive XO.
With a passive XO you want woofers that are about 3dB more sensitive than the midTweeter to avoid having to pad down the top.
Passive XO parts are big, i am goung to get a basic miniDSP HD just to figure out where that passive XO works best. If you have another amp in the closet you can quickly and cheaply biamp with a PLLXO (some care needs to be taken in the speaker design to ensure 1st order works OK — not that hard)
dave
Thanks for the quick response.
Several notes.
1. Interesting comparison to the CSS. Comparing the Wavecor to the CSS, they both - visually - appear identical. Guessing they got basket from the same source 😉 However, looking at the various stats, they are different on most fronts. Then again, when I model box sizes, they both come back with near identical .707 Q (~11.7 L).
2. My goal is to keep it sealed. Alternatively, I could go with larger woofer chamber (~13L) and downsize to the scanspeak 8530K-01, which can hit F3/53hz in sealed of that size (I believe only driver on the market that comes close in sealed config).
3. Another option is to stick with two of the the "classic" TB W5 in push-push (i.e. on on each side of speaker w/shared chamber), as they hit 707 in very small space.
4. Critical design note: this will literally be a bookshelf speaker, with books next to it on either side, and shelves above/below it. Max target size is roughly 10"H x 20"W x 10"D with only an inch around of clearance before shelf/books. Hence the desire to have the side firing woofers only play ~200hz or less.
5. You suggest sensitivity of the woofer be +3db higher than FR? The MA &.2HD's are 85.7. I don't think there's a woofer on the market at any price - in the size constraints - that has a ~89 db sensitivity. The Wavecor is 81.5, TB 81, and the scanspeak is at least 84. Can't see how to escape the sensitivity mismatch.
Several notes.
1. Interesting comparison to the CSS. Comparing the Wavecor to the CSS, they both - visually - appear identical. Guessing they got basket from the same source 😉 However, looking at the various stats, they are different on most fronts. Then again, when I model box sizes, they both come back with near identical .707 Q (~11.7 L).
2. My goal is to keep it sealed. Alternatively, I could go with larger woofer chamber (~13L) and downsize to the scanspeak 8530K-01, which can hit F3/53hz in sealed of that size (I believe only driver on the market that comes close in sealed config).
3. Another option is to stick with two of the the "classic" TB W5 in push-push (i.e. on on each side of speaker w/shared chamber), as they hit 707 in very small space.
4. Critical design note: this will literally be a bookshelf speaker, with books next to it on either side, and shelves above/below it. Max target size is roughly 10"H x 20"W x 10"D with only an inch around of clearance before shelf/books. Hence the desire to have the side firing woofers only play ~200hz or less.
5. You suggest sensitivity of the woofer be +3db higher than FR? The MA &.2HD's are 85.7. I don't think there's a woofer on the market at any price - in the size constraints - that has a ~89 db sensitivity. The Wavecor is 81.5, TB 81, and the scanspeak is at least 84. Can't see how to escape the sensitivity mismatch.
AFAIK the only difference is the label… note that that was before the current CSS, so i cn’t speak to that one. It is a very good woofer. Only potential downfall is the high price.
I looked at the LWD7 as a replacement for SDX7 (sealed) but the LWD7 needed to be vented to make the same extention. Woofers that can be used sealed are not verly common.
Ignore F3, it is not a meaningful number to humans, only electronics. Look at F6/F10.
[quote-this will literally be a bookshelf speaker[/img]
Build a separte woofer.
One of the reasons we choose W14 for Tysen V2. 4/8/16Ω, and series or parallel wiring gave a range of sensitivity numbers. 2 4Ω in series worked out close to perfect for the ~87-88 dB FF85wKeN.
dave
