Just sharing my experiences/preferences, not trying to convince anyone of anything.
There's another forum in which even a lot of pros 'seamlessly conform' to the (misleading) dogmas of the SINAD cult.
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That was not my experience with the Summas.
The 15TBX100 does not score particularly well on the Rms metric but it has Faraday rings, a relatively high Bl^2/Re-to-moving-mass ratio, and an exceptionally well-behaved cone (in that the off-axis response tracks the on-axis response beautifully).
That being said, I would probably go with the 15NDL88 in a Summa-like system today, or perhaps the Faital 15XL1200, depending on where the crossover would be.
Some of the goal posts, and in particular the SPL goal posts, were in a very different place for my studio project.
My preference would have been a distributed multi-sub system, but that was incompatible with the client's requirements.
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The characteristics I've described are probably subtle, but should become quite apparent in a direct comparison to a good midwoofer.
The 15NDL88 is indeed a proper midwoofer, just like the 15CL76. Both feature expo cones and exhibit similar FRs with extension to 3kHz, about an octave higher than the 15TBX100.
The 15TBX100 looks a bit like the JBL 2226H/J, including a well-damped break-up, which is exactly the 'culprit' (imo).
Personally, I'd prefer (Camplo's) Oberton 15NMB600s: Bl: 27.43, Mms: 89.7 g, Flux Density: 1.45 T, decent Le and almost half the RMS of the 15TBX100.
This driver is also suitable for horns.
The 15NDL88 is indeed a proper midwoofer, just like the 15CL76. Both feature expo cones and exhibit similar FRs with extension to 3kHz, about an octave higher than the 15TBX100.
The 15TBX100 looks a bit like the JBL 2226H/J, including a well-damped break-up, which is exactly the 'culprit' (imo).
Personally, I'd prefer (Camplo's) Oberton 15NMB600s: Bl: 27.43, Mms: 89.7 g, Flux Density: 1.45 T, decent Le and almost half the RMS of the 15TBX100.
This driver is also suitable for horns.
When I first saw this thread a couple years ago I thought "No" (I don't know how) because HE tweeter/horn was too directional or else too large C2C from woofer. (For example the Peavey SP-3 with CH-2 constant-directivity horn at 10-16khz was good 30-45° horizontal but only 15-20° vertical, confirmed by ear; see full specs with polars 80300649.pdf from Peavey.) Now I'd answer differently:
(2226H Fs40 Qts0.31 Vas175.6 and 1505DT-8 Fs44.2 Qts0.37 Vas198 both well-known drivers extending to ~1.5-3khz respectively.)
(2226H Fs40 Qts0.31 Vas175.6 and 1505DT-8 Fs44.2 Qts0.37 Vas198 both well-known drivers extending to ~1.5-3khz respectively.)
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@Ro808 @audiokinesis
What is your guys view on multi subs?
I like the idea of physical symmetry in my design when it comes to L vs R channels. So far I have continued to bench race designing towards stereo, corner loaded, mains. I've been entertaining pointing the lower woofers into the corner from the rear of the enclosure and use dual 15"s up front to cross to the horn
I could Use the 18"s symmetrically in a square around listening position, making the 18"s my rear subs but I just feel strongly that Dual stereo Subs image better. Its possible I am underestimating how well the 4 subs surrounding the listener could work. I think I would only entertain a symmetrical placement even with rear subs. With subs placed facing into the corner the response looks like this below... So I am not sure why rear subs would be an improvement to that, unless worried about multiple seats or something.
Also if I create an MTM, its sort of a bass array in itself, My crossover point is somewhere not far from 200hz. So the MTM would be akin to a type of bass array. Dual 18's below and dual 15's up top.
What is your guys view on multi subs?
I like the idea of physical symmetry in my design when it comes to L vs R channels. So far I have continued to bench race designing towards stereo, corner loaded, mains. I've been entertaining pointing the lower woofers into the corner from the rear of the enclosure and use dual 15"s up front to cross to the horn
I could Use the 18"s symmetrically in a square around listening position, making the 18"s my rear subs but I just feel strongly that Dual stereo Subs image better. Its possible I am underestimating how well the 4 subs surrounding the listener could work. I think I would only entertain a symmetrical placement even with rear subs. With subs placed facing into the corner the response looks like this below... So I am not sure why rear subs would be an improvement to that, unless worried about multiple seats or something.
Also if I create an MTM, its sort of a bass array in itself, My crossover point is somewhere not far from 200hz. So the MTM would be akin to a type of bass array. Dual 18's below and dual 15's up top.
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Imo an intelligently-distributed multi-sub system works very well. I've been using (and selling) them for a little less than two decades, using an early version of Earl Geddes' thinking on the subject with his permission.
The advantage of an asymmetrically-distributed multisub system is the improvement in in-room bass smoothness arising from the summation of multiple dissimilar room-interaction peak-and-dip patterns. And subjectively speaking, "smooth" bass is "fast" bass. Symmetrical configurations result in greater similarity between the room-interaction patterns of the different subs, and therefore less smoothing of the net in-room response.
Le is a tricky topic isn't it? I'm not an expert but I believe Le is sometimes misreported on purpose, matter of fact. Isn't it true that the 10khz result is lower than the 1khz result?
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This is an listening position measurement from one sub. I'd be looking to add the other sub to make a stereo pair... The graphs are not smoothed, very little filtering... how is multi sub going to help me?
Indeed.
Le of the PD.153C002 above isn't particularly low, but the impedance plot looks pretty decent.
More importantly, the 'textbook' (gradually) rising response.
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To the extent that the second sub is placed in an acoustically-dissimilar location from the first sub, there should be worthwhile smoothing of the in-room frequency response. Or conversely, the more acoustically-similar the locations of the two subs, the less net smoothing of the in-room response we can expect from adding a second sub.
Here is one argument for giving a high priority to in-room smoothness in the bass region: Notice how the equal-loudness curves start to bunch up south of 100 Hz. A difference of 6 dB at 40 Hz is subjectively comparable to a difference of 10 dB at 1 kHz. So relatively small improvement in the in-room response in the bass region pay unexpectedly large subjective dividends.
And if you've ever noticed how frustrating it is trying to dial in the perfect level for your subwoofer(s), one reason is because a small change in the SPL makes a disproportionately large change in the perceived bass loudness.
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Correct.
Correct!
And this comparison (posted on audioheritage) is telling:
"I finally got to compare these bassdrivers and want to chare my impressions with you.
Setup:
High+Mid => 2405 + 2440 joined with 2390 driven by a small Toshiba transistor. Passive Crossover with Mundorf-parts.
Low => 2235h vs. E-145 in 5 cubic feet plywood-enclosure, 2235h tuned to 30hz, E-145 tuned to 40hz. Both driven by a Pioneer(~1980) amp with 120w rms @8ohms. Crossover was a simple coil, nothing fancy....
Room => 30m² with carpet, heavy curtains and lots of furniture.... Though I wouldn`t call it overdamped!
Speaker`s and sitting position where placed about ~1meter off the walls.
We have listened to many different genre`s;
classic rock , Dire Straights , ZZ Top
80`s & 90`s Pop , Elton John , Simply Red , Yello
Electro , Malente
Techno , Moonbotica, Trentemoeller
Hip Hop , Afroman
Drums , Charly Antolini
These two drivers perform in a different manner, everybody expected this....
BUT, I expected both have equaliy many pro`s and contra`s. I have to say, the E-145 won in nearly every aspect!
It sounded way more musicaly to our ears. It just apeared to make everything right. Every single instrument sounded as real as it could be. Audio-stage was well lined up, it never sounded blurred!
The 2235h sounded kind of bored. Music just passed by, but it was nothing "special". Not as dynamic as the E-145. By far! However it offered a sovereign presentation. Even midrange sounded nice to my ears, which really impressed me when taking the heavy cone in consideration. 2235h just sounded like a good hifi-speaker. Never got annoying and sounded just flawless.
Nothing was really wrong, but nothing was perfect too.
Talking bass....
Of course, the 2235h gives a little more of that. But it isn`t a big number, really. The E-145`s bass sounds very well staggered, where as the 2235h struggles to distinguish the different bass notes. Get the wrong track and the 2235h tends to sound boomy. It isn`t really boomy, but when it is directly compared to the E-145.... which just plays more precise... I think you got me
I have to admit, the 2235h has more grunt in the very low section. That´s a fact! But we had very very few tracks where we could locate a big loss on the E-145.
With 95% of our music, we did not miss anything with the E-145.
But we got plenty of directivity and a very harmonious reproduction of music."
Correct!
And this comparison (posted on audioheritage) is telling:
"I finally got to compare these bassdrivers and want to chare my impressions with you.
Setup:
High+Mid => 2405 + 2440 joined with 2390 driven by a small Toshiba transistor. Passive Crossover with Mundorf-parts.
Low => 2235h vs. E-145 in 5 cubic feet plywood-enclosure, 2235h tuned to 30hz, E-145 tuned to 40hz. Both driven by a Pioneer(~1980) amp with 120w rms @8ohms. Crossover was a simple coil, nothing fancy....
Room => 30m² with carpet, heavy curtains and lots of furniture.... Though I wouldn`t call it overdamped!
Speaker`s and sitting position where placed about ~1meter off the walls.
We have listened to many different genre`s;
classic rock , Dire Straights , ZZ Top
80`s & 90`s Pop , Elton John , Simply Red , Yello
Electro , Malente
Techno , Moonbotica, Trentemoeller
Hip Hop , Afroman
Drums , Charly Antolini
These two drivers perform in a different manner, everybody expected this....
BUT, I expected both have equaliy many pro`s and contra`s. I have to say, the E-145 won in nearly every aspect!
It sounded way more musicaly to our ears. It just apeared to make everything right. Every single instrument sounded as real as it could be. Audio-stage was well lined up, it never sounded blurred!
The 2235h sounded kind of bored. Music just passed by, but it was nothing "special". Not as dynamic as the E-145. By far! However it offered a sovereign presentation. Even midrange sounded nice to my ears, which really impressed me when taking the heavy cone in consideration. 2235h just sounded like a good hifi-speaker. Never got annoying and sounded just flawless.
Nothing was really wrong, but nothing was perfect too.
Talking bass....
Of course, the 2235h gives a little more of that. But it isn`t a big number, really. The E-145`s bass sounds very well staggered, where as the 2235h struggles to distinguish the different bass notes. Get the wrong track and the 2235h tends to sound boomy. It isn`t really boomy, but when it is directly compared to the E-145.... which just plays more precise... I think you got me
I have to admit, the 2235h has more grunt in the very low section. That´s a fact! But we had very very few tracks where we could locate a big loss on the E-145.
With 95% of our music, we did not miss anything with the E-145.
But we got plenty of directivity and a very harmonious reproduction of music."