I know lot has been discussed after this, including waveguide differences between M2s, 4367 etc
I just wanted to know, apart from the size issue, did you find anything lacking in the sound of Summas (and in case you have also heard the NS15s).
as compared to anything you have heard later or a shortcoming with its waveguide design which would need more complex waveguide designs ? Like need for 120 deg horizontal dispersion instead of 90 ?
Maybe it was captured in posts later but I then missed it...
When I bought the Summas, I lived in a 2400' house. I tried them in a number of different rooms.
The thing I started to notice, was that you REALLY had to sit far back for them to sound their best. For instance, I had an "L-Shaped" room on my main floor, where I could listen to them from a distance of about seven meters. That worked well.
Then I moved to San Diego.
The depth of my living room was under three meters. And I could never get them to work well in that room. My issues were:
3) They needed a larger room
2) They're huge and they dominated my small room
1) They're complete overkill for a room that size. Just way more power handling and headroom than I would ever need.
The week that I sold my Summas, I measured them. And found that there's a REALLY deep null when you're off axis, vertically.
So I think that's a big part of the reason I could never get them to work in a small room: when you're seated up close, it's way easier to fall into that off-axis null.
IE, if you have a speaker with sixty degrees of vertical bandwidth, and you're seated four meters away, you're going to be located in it's vertical beam. But if you sit yourself a meter or 1.5 meters away, you can be off axis if you stand up, or if the speakers aren't carefully located.
This problem that I describe, it will be shared by ALL speakers where you have a large center-to-center spacing.
There's a few ways to solve the problem:
1) Squash the waveguide, so that the center-to-center spacing is tighter. JBL did this with the 4367.
2) Use a really low xover point. JBL did this with the M2.
If #1 or #2 aren't viable options, you'll have to arrange the speakers carefully, so that your listeners are in it's vertical beam.
The thing I started to notice, was that you REALLY had to sit far back for them to sound their best. For instance, I had an "L-Shaped" room on my main floor, where I could listen to them from a distance of about seven meters. That worked well.
Then I moved to San Diego.
The depth of my living room was under three meters. And I could never get them to work well in that room. My issues were:
3) They needed a larger room
2) They're huge and they dominated my small room
1) They're complete overkill for a room that size. Just way more power handling and headroom than I would ever need.
The week that I sold my Summas, I measured them. And found that there's a REALLY deep null when you're off axis, vertically.
So I think that's a big part of the reason I could never get them to work in a small room: when you're seated up close, it's way easier to fall into that off-axis null.
IE, if you have a speaker with sixty degrees of vertical bandwidth, and you're seated four meters away, you're going to be located in it's vertical beam. But if you sit yourself a meter or 1.5 meters away, you can be off axis if you stand up, or if the speakers aren't carefully located.
This problem that I describe, it will be shared by ALL speakers where you have a large center-to-center spacing.
There's a few ways to solve the problem:
1) Squash the waveguide, so that the center-to-center spacing is tighter. JBL did this with the 4367.
2) Use a really low xover point. JBL did this with the M2.
If #1 or #2 aren't viable options, you'll have to arrange the speakers carefully, so that your listeners are in it's vertical beam.
According to this: MiniDSP : JBL M2 crossover with the openDRC (1/5)
The D2430K is only down about 6dB at 450hz!
I'm not sure how they keep it from exploding, but that's a brutal xover.
The D2430K is only down about 6dB at 450hz!
I'm not sure how they keep it from exploding, but that's a brutal xover.
Yea, that is.
Jbl 2435hpl 1.4” no eq, 750hz @ 24db LR (you are 6db down there), then swing xover to 1khz when blasting it.
Seemed like it was struggling otherwise.
Maybe the coax compression driver has less garble, being a 2 way, versus running a 3” diaphragm 1.4” hole from 800hz all the way up to 20khz.
Jbl 2435hpl 1.4” no eq, 750hz @ 24db LR (you are 6db down there), then swing xover to 1khz when blasting it.
Seemed like it was struggling otherwise.
Maybe the coax compression driver has less garble, being a 2 way, versus running a 3” diaphragm 1.4” hole from 800hz all the way up to 20khz.
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I cross the BMS 4594 on a SEOS 24 at 450hz as well. No issues with living room listening levels.
The 4367 uses an even lower crossover freq, 700Hz vs M2's 800Hz, though its slope is not known..
@Patrick Bateman
This is one interesting option with same HF driver as JBL 705/8
C211 | JBL Professional Loudspeakers
And the other models in the series 200 Series | JBL Professional Loudspeakers
This is one interesting option with same HF driver as JBL 705/8
C211 | JBL Professional Loudspeakers
And the other models in the series 200 Series | JBL Professional Loudspeakers
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Something I've been curious about; why squash the waveguide so heavily, then leave what appears to be an inch or more of empty baffle between it and the LF driver?
Attachments
I guess one is only "tickling" them even at loud monitoring levels. IIRC its rated power is 200 Watts. In the M2 the coils are wired in series, giving 32 Ohms. And then there is a voltage divider in front of it. I guess it doesn't consume a lot of power even when that beefy crown amp the M2 is usually driven by is run almost at clipping.
I have some 2426 on 2344 horns. I run them down to 1 kHz approximately but I rember that the datatsheet mentioned that the combo could be used down to 500 Hz if power stays below 10 Watts or so.
Regards
Charles
Those blue baffle JBLs are for consumer market, and their cosmetics are at least as important as their sound.
JBL has a new 12" 4349 4349 | 12-inch (300mm) 2-way Studio Monitor Loudspeaker
which again has waveguide like M2 than 4367
They had 8" 4306 4306 | 8-inch (200mm) 2-way Studio Monitor Loudspeaker which seems to have different waveguide from 4367 as well as M2
which again has waveguide like M2 than 4367
They had 8" 4306 4306 | 8-inch (200mm) 2-way Studio Monitor Loudspeaker which seems to have different waveguide from 4367 as well as M2
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This one is interesting. JBL has been sticking to bi-radial based horn for consumer "studio monitor" line for a long time, and this is the first one with M2 like waveguide. It was most probably because average consumer who would buy JBL today want to see more classical "JBL" look, so I'm very curious how this product would success in the market.
In 80's, when JBL released 4425, it took some time the new look of the horn to be accepted by the market. This would be 4425 of 2020, let's see.