Push-Push 12's for Sachikos

[GusGus111]

I am considering a push-push design using 2 Dayton 12" woofers instead of a single sealed 15. Below is the URL for the driver in mind:

Parts-Express.comayton SD315-88 12" Shielded DVC Subwoofer | subwoofer sd315-88 12" subwoofer dvc dual voice coil dayton subwoofer dayton dvc dayton 12" woofer daytonDVC030209 Upto15PerOffDASubs

I chose it because of the high extension to integrate better with my sachiko cabs and the relatively cheap cost. I plan to use the sub for music (that needs it), but mostly HT.

My questions are:

1. Will this design fit well sonically with my Sachiko cabinets (tight and clean), or what might be better? I have somewhat limited space and the sub will be in a long, fairly narrow room with normal ceilings.

2. Is this a decent driver for the price? I'd rather not spend more than $50/driver.

3. When designing the cabinet, do I just double the volume compared to a single sealed cab for the same driver? Also, does a square or perhaps slightly taller cab work as well as anything else?

I'm planning on the wiring the DVC of the above driver as such (top image):



I want to do this right, of course, so I do appreciate your comments.

Thanks,
-Gus

[bjorno]

Originally Posted by GusGus111

I am considering a push-push design using 2 Dayton 12" woofers instead of a single sealed 15. Below is the URL for the driver in mind:

Parts-Express.comayton SD315-88 12" Shielded DVC Subwoofer | subwoofer sd315-88 12" subwoofer dvc dual voice coil dayton subwoofer dayton dvc dayton 12" woofer daytonDVC030209 Upto15PerOffDASubs

I chose it because of the high extension to integrate better with my sachiko cabs and the relatively cheap cost. I plan to use the sub for music (that needs it), but mostly HT.

My questions are:

1. Will this design fit well sonically with my Sachiko cabinets (tight and clean), or what might be better? I have somewhat limited space and the sub will be in a long, fairly narrow room with normal ceilings.

2. Is this a decent driver for the price? I'd rather not spend more than $50/driver.

3. When designing the cabinet, do I just double the volume compared to a single sealed cab for the same driver? Also, does a square or perhaps slightly taller cab work as well as anything else?..

..I want to do this right, of course, so I do appreciate your comments.

Thanks,
-Gus

Hi GusGus111,

My answer for the question 1 and 2: Depends on preferences and budget.

Question 3.: No and yes, a tall design (See picture # 2) is IMO preferable if 2 subs are made and placed close to the main speakers,

..I chose it because of the high extension to integrate better with my sachiko cabs and the relatively cheap cost. I plan to use the sub for music (that needs it), but mostly HT..

Note; The following is based on IME when placing subs (100-150L closed box) close to FR equipped *Schmack horns (picture#3) and not if the subs are placed far (typically > 3m) away from the horn mouths.

*I build a lot of in the 70ties in order to improve the very low FR end, i.e. < 70 Hz.

If you add subs XO: ed high to speakers that have distributed sum of FR: s, i.e. the driver itself + the sum of two mouths that have a wideband overlap in the region of upper bass -lower midrange and where the subs (woofers) have an extended BW, FR > -20 dB at 250 Hz and where an asymmetric room undoubtedly load exists for the different mouths depending of their heights compared to the floor distance, the vertical phantom enlargement (i.e. phantom spread) would IMO be huge, hanging down towards the floor.

In other words I wouldn’t recommend placing subs/extra woofers near the main speakers at the floor level in order to augment the FR if there is substantial FR output above 250 Hz from the Sachiko horn mouths.

A way to avoid this occurring flaw when using extended response subs (woofers), is if the drivers are placed within about +- 5 degrees of vertical azimuth counted from the main drivers and horizontally as close to the main drivers as possible.

IMO, if the distributed response from the mouths are restricted and essentially do not contain frequencies above 250 Hz, a floor placed sub could be added but only if the sub FR at 250 Hz is about 20 dB down.

Maybe not necessary, but this condition could be improved for the mains too, by slightly stuffing the rear side of the main FR driver if the FR below contains large amplitude ripple (>+3dB) like for an unstuffed speaker operating at the quarter wave.

To argument the mid-bass, upper-bass FR area only: I wouldn’t only placing full BW (BW>250Hz) subs with drivers near the floor if I had two Sachiko’ s, but I would consider adding symmetrically placed mid-bass drivers at max lambda/4 distance from the FR drivers based on a chosen overlap frequency, XO:ed at or lower than 250 Hz thou.

The mid bass drivers should be good for about an f-3dB of at least 50 Hz at min. Then I would add subs with drivers close to the floor where one of the subs, a T-TQWT of course, J the main sub is placed near a corner, XO:ed at or below 80 Hz.

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