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JBL LSR 308 in the house

RayDunzl

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#82
Data point:

Alright, here is what tonight's pondering got me:

I DRC'd both the ML and JBL to the same "flat" level, and did an overlay of the Waterfall display in REW.

But the JBL (green) waterfall obscured the overlay of the ML (gold) waterfall.

I had to reduce the level of the JBL SPL by 9dB to get the body of the waterfalls to match up and poke through each other some.

The key point to me is that the ML has about a 9dB "direct sound" advantage over the JBL in the room, rather, narrow vs wide dispersion, since the brands don't mean anything here.

upload_2016-12-23_2-49-19.png


Mathematically adjusted relative levels to get the waterfall more aligned:

upload_2016-12-23_2-51-32.png


Original "matched" levels:

upload_2016-12-23_3-1-1.png



Original Waterfall, matched "direct" levels, JBL (green) overlaid with ML (gold)

upload_2016-12-23_3-3-32.png


Compare original using Impulse Response:

upload_2016-12-23_3-4-28.png
 

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watchnerd

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#83
Data point:

Alright, here is what tonight's pondering got me:

I DRC'd both the ML and JBL to the same "flat" level, and did an overlay of the Waterfall display in REW.

But the JBL (green) waterfall obscured the overlay of the ML (gold) waterfall.

I had to reduce the level of the JBL SPL by 9dB to get the body of the waterfalls to match up and poke through each other some.

The key point to me is that the ML has about a 9dB "direct sound" advantage over the JBL in the room, rather, narrow vs wide dispersion, since the brands don't mean anything here.

View attachment 4122

Mathematically adjusted relative levels to get the waterfall more aligned:

View attachment 4123

Original "matched" levels:

View attachment 4125


Original Waterfall, matched "direct" levels, JBL (green) overlaid with ML (gold)

View attachment 4126

Compare original using Impulse Response:

View attachment 4127
I applaud the effort.

But I have to admit I find the overlayed waterfalls hard to digest.

I think I'd find it easier to just look at them separately side by side.

Interesting that the room-induced suckout at 40-50 Hz seems worse on the ReQuests.

FWIW, I have 2 pairs of MLs at home, a vintage set of Sequel II and a newish pair of Electromotions. Plus I have my 305s.
 

RayDunzl

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#85
Interesting that the room-induced suckout at 40-50 Hz seems worse on the ReQuests.
The left rear corner of my room is open to the kitchen and beyond.

For reasons I can't calculate the phase of the bass around 50Hz goes anti-phase at the listening position.

Either speaker is much flatter, but together they create a steep phase-induced drop at the Listening/measuring point.

Right now, the woofer of the JBLS are 50" off the floor, the reQuest (can't see the woofer easily) about 18" up, and latest measuring include two Cheezewoofer Wattless 15" subs (stacked under the JBL).

Here's a left/right/combined 1/12 octave smoothed DRC'd to flat reQuest + subs in outboard stereo position measurement.

upload_2016-12-23_13-52-28.png


Unsmoothed Bass Phase detail of left/right. 180 degree phase difference at 48Hz and around it.

upload_2016-12-23_13-57-21.png



It's not noticeable on music, I wouldn't have known it was there without measuring. It's still rather academic, it seems. Someday I'll disperse the subs and see where it goes.
 

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RayDunzl

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#86
FWIW, I have 2 pairs of MLs at home, a vintage set of Sequel II and a newish pair of Electromotions. Plus I have my 305s.
I have a pair of SL3 in the bedroom, myself.
 

Blumlein 88

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#88
Data point:

Alright, here is what tonight's pondering got me:

I DRC'd both the ML and JBL to the same "flat" level, and did an overlay of the Waterfall display in REW.

But the JBL (green) waterfall obscured the overlay of the ML (gold) waterfall.

I had to reduce the level of the JBL SPL by 9dB to get the body of the waterfalls to match up and poke through each other some.

The key point to me is that the ML has about a 9dB "direct sound" advantage over the JBL in the room, rather, narrow vs wide dispersion, since the brands don't mean anything here.

View attachment 4122

Mathematically adjusted relative levels to get the waterfall more aligned:

View attachment 4123

Original "matched" levels:

View attachment 4125


Original Waterfall, matched "direct" levels, JBL (green) overlaid with ML (gold)

View attachment 4126

Compare original using Impulse Response:

View attachment 4127

Doesn't the waterfall comparison mainly show that the ML decays much further in the first few milliseconds vs the JBL. So for the bulk of the undecayed sound you need to lower the JBL so it doesn't obscure the remaining decay levels of the ML. I suppose this is a round about way of saying what you are. The direct sound of the more directional MLs has a 9 db advantage over the more dispersive JBL speakers.

Looks like the first 8 or 10 milliseconds is where that difference lies. I take it the distance to your walls and such would somewhat fit that idea.
 
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watchnerd

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#89
Doesn't the waterfall comparison mainly show that the ML decays much further in the first few milliseconds vs the JBL. So for the bulk of the undecayed sound you need to lower the JBL so it doesn't obscure the remaining decay levels of the ML. I suppose this is a round about way of saying what you are. The direct sound of the more directional MLs has a 9 db advantage over the more dispersive JBL speakers.
It's also energy storage -- electrostats have much less energy storage than dynamic speakers.
 

Blumlein 88

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#90
I also have the same gear as do many others.
How about doing a tutorial on doing some of these basic measurements you post
Amir did a basic step-up tutorial of REW but the promised followup still await.
http://audiosciencereview.com/forum...om-measurement-tutorial-for-dummies-part-1.4/
I find the REW help files a bit (lot) confusing and hard to follow.
I agree with Ray on this Sal. Start a thread on it. Would be good for people in the future to learn from. I use REW some though not as often as Ray does. Ray and I and others could help you figure it out. I do remember when I first used it the software was a bit baffling. Some ways it works are still less than ideal from a UI standpoint. Also the help files were not of great benefit to me either. A common failing of free or open source software. I learned more just running it and playing with things to see what did what. Also like much open source software other users are where the real help comes from in the end.
 
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Blumlein 88

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#91
It's also energy storage -- electrostats have much less energy storage than dynamic speakers.

Yes I know. The density of the mylar is not too different than air. So it gets quickly damped and stores very little energy. Ray's plots would make me lean toward the main difference being dispersion however.
 

Thomas savage

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#92
I agree with Ray on this Sal. Start a thread on it. Would be good for people in the future to learn from. I use REW some though not as often as Ray does. Ray and I and others could help you figure it out. I do remember when I first used it the software was a bit baffling. Some ways it works are still less than ideal from a UI standpoint. Also the help files were not of great benefit to me either. A common failing of free or open source software. I learned more just running it and playing with things to see what did what. Also like much open source software other users are the where the real help comes from in the end.
Keith was saying he was bit baffled by the new version of REW I seem to remember so a REW thread would be great.
 

RayDunzl

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#93
From listening position, first 5 ms in .5 ms slices, 1/3 smoothing, 2ms rise time:

JBL
upload_2016-12-23_15-34-23.png


MartinLogan
upload_2016-12-23_15-35-18.png
 
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RayDunzl

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#96
The room is 18 x 14 x 9

Listening is 10 feet.

Left rear corner is open to kitchen etc.
 

watchnerd

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#97
The room is 18 x 14 x 9

Listening is 10 feet.

Left rear corner is open to kitchen etc.
Thanks.

What sort of SPLs do you typically listen at?

I think I saw earlier where you had 95 dB at 1 m / 70 dB at listening position? Or did I read that wrong?
 

RayDunzl

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#98
Softly about 70 or so with 90 or so peaks, and rather loudly 85 or so with 105 peaks, Z weighted, at the listening position.

My measured extreme was a somewhat calibrated drum solo (first couple of seconds) that peaked at 116.9dBz, it sounded like Terry Boxxio had come to visit but also felt a bit dangerous...

Here's right now with the JBL:

upload_2017-1-6_2-5-30.png
 
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watchnerd

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#99
Softly about 75 or so with 95 or so peaks, and loudly 85 or so with 105 peaks, Z weighted, at the listening position.

My measured extreme was a somewhat calibrated drum solo (first couple of seconds) that peaked at 116.9dBz, it sounded like Terry Boxxio had come to visit but also felt a bit dangerous...
116 dB?!

I don't think I've ever played that loud at home.
 

RayDunzl

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116 dB?!

I don't think I've ever played that loud at home.
It was quite loud, imagine someone pounding on your speakers with a baseball bat.

So, it was only a Momentary Lapse of Reason.

Krell FPB 350 mcx - 350/700/1400W 8/4/2 ohms. It's the little one in the series.

Speakers claim 500w so, I wasn't too far off the mark, but it isn't something I do.

110dB peak might show when extra loud sometimes, but that's like on Beer Saturdays with dynamic combos so the sustained is not 110dB.

That was with the Martin Logans, not the JBLs, which I haven't tortured yet. They would seem to have their own limits (protections available in the amplifier chip), so, ?

---

I tried to calculate the power based on 87dB 2W sensitivity and got 1965W, so, I'm not sure if I'm mixing RMS and Peak or what, in that little exercise.
 
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