Yes.
@ BP1 Thanks
And yeah, who cares about subs running up higher.
Only time I've ever done that was seeing if a sealed 18n862 sub could reach smoothly up to 300Hz,
that a B&C dcx464 CD / me464 horn combo could go down to..
Although my preference also would be using subs below ~120 Hz, but many top cabinets that roll off well above that point- for instance the popular sealed co-ax 12" DSL SM-80 starts rolling off ~200Hz, -12dB at 100Hz.
The upper response of course affects the crossover choice- the 120Hz LR24 is -15dB at 240Hz, a 120Hz LR12 would only be -3dB at 240Hz.
The "V" twin has no major cancellations below 250Hz, while your 2x18 PPSL using the same drivers has a notch at 160Hz and a steep drop above 200Hz.
Thanks for posting the raw response, it's interesting to compare upper response to see what is required to "fix" it, and the useful range.
Art
The unity/synergy horn uses a bms 4598he CD, four 4" 4NDF34 mids, and two 12" 12pr320 lows.
Horn crosses at 100 Hz to the sub.
Yep, all that for sure.
One of the design goals with this new guy, was to close down c2c spacing, with the 18"s and my syn horns.
It's now at about 1/4 WL to 147Hz.
Which lets the 96 dB/oct lin phase LR xovers I use, give me me 1/4 spacing down to -30dB.
With the prior PPSL sub, I could only xover at 90 Hz or below to achieve 1/4 Wl spacing down to -30dB.
a big part of the whole last syn11 effort, that put 18"s into the physical syn horn, was to achieve the 1/4 spacing to lows throughout critical xover range.
This new sub gives it....as long as below120 Hz, and at 96 db/oct.
Just got stereo syn10 and new subs up and running. Seems worth all the effort so far
Mark,
At any listening positions other than way off axis vertical (like laying on the ground with your head near the port..) the thinner sub has slightly less center to center spacing difference to the top cabinet than the wider sub.
That said, the new subs look way cooler with the tops and go louder lower, so definitely worth the effort!
Art
Hi Art, I don't think you're getting what i was saying...or I'm not getting what you're saying...
The horizontal 1/4 WL constraint of either the old or new, has not been an issue. New has about 24", old had about 16"
Issue has been with the vertical c2c constraint with the prior PPSL. It's quite reduced with the new one.
New has about 23" c2c. Old had 33"
Vertical summations matter as much at low freq as do horiz, I think.
What's your take?
If I go all out and take diagonals as what counts, c2c is still simply much better with this new guy.
About 135hz on diag
The horizontal 1/4 WL constraint of either the old or new, has not been an issue. New has about 24", old had about 16"
Issue has been with the vertical c2c constraint with the prior PPSL. It's quite reduced with the new one.
New has about 23" c2c. Old had 33"
Vertical summations matter as much at low freq as do horiz, I think.
What's your take?
If I go all out and take diagonals as what counts, c2c is still simply much better with this new guy.
About 135hz on diag
My last post was unclear- the old sub has 10" more c2c vertical separation, but a more compact horizontal width, so off axis c2c horizontal separation is slightly less than the wider new sub.
Since we move left and right (horizontal) to the stack, but don't vary much vertically, horizontal summation matters more.
That said, with primarily mono low frequency, and stereo stack c2c distance different in every horizontal position other than center, the discussion is rather academic, but here it is:
For your ground stack, the vertical c2c distance difference won't impact summation.
My take is at a few meters or more distant your ears will be nearly equidistant (under 1/8th wavelength, less than 45 degrees of phase difference) between the two low frequency sources in the 100Hz range, even if one was on the ground and one at head level.
For example, at 8' to the top cabinet center to your ear, 5' (60") c2c to the sub below, it's 9' to your ear, just 1' (12") further distance.
Move the sub up to 2' (24") center to center of the top, the difference drops to 0.76' (9.12").
A difference of 4" (100mm) won't make an appreciable change on the summation of two sources emitting a 100Hz 11.3' wavelength. As you move further from the stack, the distance difference becomes even less.
New has about 23" c2c, old had 33", a difference of just 10" center to center at 100 Hz will make no difference.
The larger front face of the new cabinet will make an increase in the forward directivity of both the sub and the top compared to the skinny old cabinet.
Art
Thanks for taking the time to write all that out.
And yep, I'm very familiar with all those lines of reasoning.
For me, the sub-to-main combo is the hardest to measure. Subs are easy, do to driveway. Measuring my mains, built for generally around 100Hz up, are more challenging in. But my outdoor, off raised deck, measurement rig, gives me a reflection free path of at least 25 ft..so not bad....for 100Hz up..
Other than dragging subs and main onto driveway, I dunno good combined measurement method.
So...I say screw it, get the best c2c I can between sub and main...and it can't help but help.
Plus I heard it does/did help with syn11 which got reponse down to 40Hz in one horn.
Guess I'm just a keep all summed response, ALL the way thru xover region, with 1/4 WL, junkie...lol.
Anybody that thinks subs are pure omni, just ain't had enough experience to know better.
And yep, I'm very familiar with all those lines of reasoning.
For me, the sub-to-main combo is the hardest to measure. Subs are easy, do to driveway. Measuring my mains, built for generally around 100Hz up, are more challenging in. But my outdoor, off raised deck, measurement rig, gives me a reflection free path of at least 25 ft..so not bad....for 100Hz up..
Other than dragging subs and main onto driveway, I dunno good combined measurement method.
So...I say screw it, get the best c2c I can between sub and main...and it can't help but help.
Plus I heard it does/did help with syn11 which got reponse down to 40Hz in one horn.
Guess I'm just a keep all summed response, ALL the way thru xover region, with 1/4 WL, junkie...lol.
Yes. Big yes. That was one of the things I did not like about the huge sub carts that went with syn11....too damn directional. And again, never low-passed above 100Hz, and steep as heck.
Anybody that thinks subs are pure omni, just ain't had enough experience to know better.
Lid on.
Gotta say...I'm listening to a pair of these subs in stereo right now, under some unity/synergy horns.
ROCK.
25 Hz response,..... smooth and level... good to high SPL......just asking to be unleashed and let breathe..and let me work out any resonances LOL
Gotta say...I'm listening to a pair of these subs in stereo right now, under some unity/synergy horns.
ROCK.
25 Hz response,..... smooth and level... good to high SPL......just asking to be unleashed and let breathe..and let me work out any resonances LOL
Last edited: