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JBL LSR 308 in the house

RayDunzl

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#1
I have Christmassed myself with a pair of powered monitors.

http://www.jblpro.com/www/products/recording-broadcast/3-series/lsr308

upload_2016-12-12_22-34-6.png


Oops... Measurements aren't true below 200Hz - see post #5 below

Here are some initial measurements. They are on barstools directly in front of my main speakers. The microphone is located at the center of my brain between my ears at the listening position.

Sweep and Pink Noise, both speakers playing - 1/6 octave smoothing on the sweep, 1/48 on the pink:

upload_2016-12-12_22-35-43.png


Left, right, and both sweep at 1/12th octave smoothing:

upload_2016-12-12_22-40-4.png


Impulse (not normalized) for left, right, and both:

upload_2016-12-12_22-47-43.png


Step (not normalized) and Inverted for left, right, and both:

upload_2016-12-12_22-49-9.png


Distortion for both speakers - numbers at 1kHz:

upload_2016-12-12_22-53-14.png


Distortion for both speakers, normalized to fundamental, displayed as percent with 80dB fundamental:

upload_2016-12-12_22-59-2.png


Distortion for both speakers, normalized to fundamental, displayed as dB relative:

upload_2016-12-12_22-59-59.png


Waterfall, both speakers, 1/6 averaging, dropping into the ambient/measurement noise floor:

upload_2016-12-12_23-4-8.png


Impulse Response both speakers, dBFS setting, 350ms:

upload_2016-12-12_23-9-28.png
 
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iridium

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#2
Merry, merry Christmas.

iridium
 

Sal1950

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#3
Here are some initial measurements. They are on barstools directly in front of my main speakers. The microphone is located at the center of my brain between my ears at the listening position.
Quite impressive really.
 

RayDunzl

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#5
Phase:

Totally insane vs what I'm used to seeing, so I don't know what to think, except it is similar to the other cone /dome speakers I have (Infinity P-363)

upload_2016-12-12_23-22-26.png


With Music:

Hiromi - Alive - but on CD

FR trace bumped up 10dB to get it out of the way.

I compare the in-room with the left/right coming out of the CD player, and at approximately the same in room decibel level as what's on the CD.

The port is tuned to 38Hz, so anything below that is missing in action, a little soft in the 40-50Hz range, which is my room and mic position. A little soft at 60-75Hz. there's a hole around 150Hz that I'm not used to seeing, may be just the slight difference in position - about 16 inches in front of the other speakers.

Here's an hour of aggregated measurement in a style I'm used to looking at:

Top - in room FR sweep for reference (bumped up 10dB on the display) - red is prior peaks, black the current instantaneous RTA that moves and makes the peaks.
Middle, the left channel of the CD, Bottom, the right.

SPL Meters are somewhat carefully calibrated, despite the red numbers on the CD SPL that indicate they aren't. This version of Multi REW forgets you calibrated it. Maybe the newer one doesn't, haven't tried it yet.

upload_2016-12-13_0-28-30.png


The little peaks at 16 18 21 kHz in-room might be chair squeak, didn't notice them before I sat down again. Maybe not, didn't reproduce them.
 
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RayDunzl

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#6
So what does it sound like for Pete's sake?
Gosh, I don't know.

There aren't any trained listeners, professional audio reviewers, or randomly selected college students here for me to statistically sample and work up a result on that subject for peer review.

I can say I'm not noting any unusual scientifically acceptable and footnoted dictionary-defined emotional response aberrations, if that helps.



As usual, none of the above.

Maybe one not listed:

Relief. While amateurishly researching others opinions of these devices many of them were not happy with a little hiss they make. I haven't measured it yet, but it isn't a problem with my deaf ears.

Putting my ear up to the waveguide I could hear a little "sea-shell" sound, not sure if it's the reflection of the ambient room noise or something new coming from the tweeter dome. It will be scrutinized.
 

Blumlein 88

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#7
Well I have their little brothers the LSR305. Used as center and surrounds in vid setup or monitors for recordings I make. Pretty awesome to get this level of performance this cheap. If only Harman would make some electrostats for like $1000 or something.

So using the MP3 emotional chart (which I think all subjective review mags should implement immediately) :p I had the following reactions with the little brothers monitoring my recordings.

Comic, because I was laughing at how good they were.
Scary, because I thought I must be off my rocker to get this much for so little money.
Angry, because I knew people who spent twice as much for basically garbage sound.
then finally...............

Happy.

BTW, I got about the same kind of goofy phase graph as you with REW. I need to dig up where I did those measurements.
 

RayDunzl

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#8
En route to the Moon, approximately 200,000 miles (320,000 km) from Earth, Mission Control asked John Swigert to turn on the hydrogen and oxygen tank stirring fans, which were designed to destratify the cryogenic contents and increase the accuracy of their quantity readings.

(Service Module explodes)

55:55:20 - Swigert: "Okay, Houston, we've had a problem here."
55:55:28 - Lousma: "This is Houston. Say again please."
55:55:35 - Lovell: "Houston, we've had a problem. We've had a main B bus undervolt."
55:55:42 - Lousma: "Roger. Main B undervolt."


At least I'm not four fifths of the way to the Moon.

The graphs above have some lies in them... So, I'll have to take a mulligan and replace them...

There was still some external EQ applied... this partly curvy red line here is supposed to be flat, and look! It's not...

upload_2016-12-13_1-23-14.png


I was wondering why they didn't exhibit the usual "We think this is best and so should you" tubby boom-boom bass curve. However, it does show they'll be good down to 30Hz without any boost. I was beginning to miss my 31.5Hz low string on the 5 string electric bass.

It's not too bad, the hump is correctible here in the Simulator. It's only about 10dB hot. This is an example of what it really looks like here - "flat" firing into the room vs the CD source:

upload_2016-12-13_1-37-17.png
 

RayDunzl

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#11
They're on sale ($50 off each one) till the end of the year here.
 

RayDunzl

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#12
Here's the hiss - microphone 1" from the tweeter:

upload_2016-12-13_4-19-48.png


And with the speaker powered off:

upload_2016-12-13_4-22-1.png


And back at listening position, about 10 feet away, speakers on:

upload_2016-12-13_4-26-18.png
 

RayDunzl

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#13
Distortion levels are higher than my panels.

JBL

upload_2016-12-16_16-6-5.png


Martin Logan

upload_2016-12-16_16-9-2.png



Trouble with cheap speakers normally is that their suspensions are not too brilliant - unless you thrash them, the suspensions never loosen up properly, they will sound dull and lacking in detail.
The rubber surrounds on these are very soft, just a light touch and they fully deform, like an inflated but unpressurized bicycle tire tube.

It's difficult for me to imagine there is much loosening up to be had there... Might happen... Stiff, as in limiting excursion, would contribute to the 3rd harmonic distortion measurement...

Fundamental sine wave 100Hz, third harmonic 300Hz at -20dB, and combined.

upload_2016-12-16_16-44-33.png


I can't see or touch the spider.

 

RayDunzl

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#14
Power consumption: 3W idle.

Power Factor: 0.27, rising a little (.30) with volume.

Plus whatever you are sending to the speakers.
 

fas42

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#15
The rubber surrounds on these are very soft, just a light touch and they fully deform, like an inflated but unpressurized bicycle tire tube.

It's difficult for me to imagine there is much loosening up to be had there... Might happen... Stiff, as in limiting excursion, would contribute to the 3rd harmonic distortion measurement...

Fundamental sine wave 100Hz, third harmonic 300Hz at -20dB, and combined.

View attachment 4049

I can't see or touch the spider.

It may be the spider, and there's also the suspension of the treble unit to consider. The term I've heard being used to describe this behaviour is https://en.wikipedia.org/wiki/Stiction - to my mind it's the reason why panels, like your MLs, always have an intrinsic advantage ...
 

RayDunzl

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#16
Treble.

JBL - Crossover 1800Hz. Still throws that 3rd in there.

upload_2016-12-16_17-18-15.png


Martin Logan - Crossover 180Hz.

upload_2016-12-16_17-14-13.png
 

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fas42

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#17
Looks like the sort of distortion figures they've been getting for decades - reasonable cones do in the range 4o to 60 dB down, a better panel can push below 60dB.
 

fas42

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#18
Of course, the real question is, how different do your normal rig, and the JBLs "sound" from each other with different music, at different levels? Pass the blindfold test, that sort of thing ...
 

RayDunzl

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#19
I feel confident to tell them apart on these criteria at the listening position:

Spatial
Deep Bass

Maybe less able to do so off axis, not that I've tried, but just using the "forgot which I was listening to while casually listening" criteria.

They're not far off from each other. Listening position FR, normalized at 1kHz, no DRC, 1/3 octave smoothing.

Gold - JBL Green - reQuest

upload_2016-12-16_19-0-50.png
 

fas42

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#20
What do you mean by "spatial" - the sense of how the recording playback and room interact to create a sense of space, hearing the acoustic cues on the recording, ... ?
 

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