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JBL Professional 708P Bi-Amplified 8-Inch Master Reference Monitor

hardisj

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This is copy/pasted from my website. Therefore, there may be some formatting things that go awry when pasted here. Feel free to view the review natively on my site linked below. Otherwise, enjoy it here!
https://www.erinsaudiocorner.com/loudspeakers/jbl_708p/

Yep, Amir measured this. Same exact one, actually. We do show some differences, mainly in the HF IIRC. I believe it was discovered that the speaker in Amir's test was angled a bit down or up... don't recall... and that likely explains the difference. It was discussed in another thread but I don't know where and I don't want to go dig it up. Maybe @MZKM remembers because it was his data that showed the error. Anyway....

JBL Professional 708P Bi-Amplified 8-Inch Master Reference Monitor
  • Sunday, May 23, 2021
DSC01944.JPG


Foreword / YouTube Video Review
The review on this website is a brief overview and summary of the objective performance of this speaker. It is not intended to be a deep dive. Moreso, this is information for those who prefer “just the facts” and prefer to have the data without the filler.
However, for those who want more - a detailed explanation of the objective performance, and my subjective evaluation (what I heard, what I liked, etc.) - please watch the below video where I go more in-depth.
<<coming soon>>


Information and Photos

The JBL 708P is a powered 2-way Studio Monitor featuring the JBL 728G 8-inch woofer and JBL 2409H compression driver in the JBL Image Control Waveguide. It features 1 x XLR-1/4” balanced combination analog audio input and 1 x XLR AES3 format digital input with 1 x XLR pass-through output. The following is from the manufacturer’s website:
JBL 708P is the self-powered reference monitor for critical music recording, film post and broadcast production applications. The 708P leverages new patent-pending driver technologies and JBL’s renowned Image Control Waveguide to deliver extraordinary output, stunning detail, an expansive soundstage, and greater accuracy in a broad range of rooms. 708P delivers several times the output of other comparably-sized studio monitors, providing significantly greater dynamic range and greater working distances. 708P features analog and digital inputs and sample rate converters. AES/EBU digital inputs allow connectivity with a broad range of production hardware, including digital audio workstations (DAW), mixing consoles and digital playback hardware with sample rates of up to 192 kHz.
MSRP is about $1800 USD for a single speaker.
DSC01943.JPG

DSC01948.JPG




CTA-2034 (SPINORAMA) and Accompanying Data
All data collected using Klippel’s Near-Field Scanner. The Near-Field-Scanner 3D (NFS) offers a fully automated acoustic measurement of direct sound radiated from the source under test. The radiated sound is determined in any desired distance and angle in the 3D space outside the scanning surface. Directivity, sound power, SPL response and many more key figures are obtained for any kind of loudspeaker and audio system in near field applications (e.g. studio monitors, mobile devices) as well as far field applications (e.g. professional audio systems). Utilizing a minimum of measurement points, a comprehensive data set is generated containing the loudspeaker’s high resolution, free field sound radiation in the near and far field. For a detailed explanation of how the NFS works and the science behind it, please watch the below discussion with designer Christian Bellmann:



The reference plane in this test is at tweeter per the manual.

Measurements are provided in a format in accordance with the Standard Method of Measurement for In-Home Loudspeakers (ANSI/CTA-2034-A R-2020). For more information, please see this link.

CTA-2034 / SPINORAMA:
CEA2034%20--%20JBL%20708P.png

Early Reflections Breakout:
Early%20Reflections.png

Estimated In-Room Response:
Estimated%20In-Room%20Response.png

Horizontal Frequency Response (0° to ±90°):
SPL%20Horizontal.png

Vertical Frequency Response (0° to ±40°):
SPL%20Vertical.png

Horizontal Contour Plot (not normalized):
JBL%20708P_Horizontal_Spectrogram_Full.png

Horizontal Contour Plot (normalized):
JBL%20708P%20Beamwidth_Horizontal.png

Vertical Contour Plot (not normalized):
JBL%20708P_Vertical_Spectrogram_Full.png

Vertical Contour Plot (normalized):
JBL%20708P%20Beamwidth_Vertical.png



Additional Measurements

On-Axis Response Linearity
JBL%20708P%20FR_Linearity.png
“Globe” Plots
These plots are generated from exporting the Klippel data to text files. I then process that data with my own MATLAB script to provide what you see. These are not part of any software packages and are unique to my tests.
Horizontal Polar (Globe) Plot:
This represents the sound field at 2 meters - above 200Hz - per the legend in the upper left.
JBL%20708P_360_Horizontal_Polar.png


Vertical Polar (Globe) Plot:
This represents the sound field at 2 meters - above 200Hz - per the legend in the upper left.
JBL%20708P_360_Vertical_Polar.png


Harmonic Distortion
Harmonic Distortion at 86dB @ 1m:
JBL%20708P%20--%20Harmonic%20Distortion%2086dB%20%40%201m.png

Harmonic Distortion at 96dB @ 1m:
JBL%20708P%20--%20Harmonic%20Distortion%2096dB%20%40%201m.png

Dynamic Range (Instantaneous Compression Test)
The below graphic indicates just how much SPL is lost (compression) or gained (enhancement; usually due to distortion) when the speaker is played at higher output volumes instantly via a 2.7 second logarithmic sine sweep referenced to 76dB at 1 meter. The signals are played consecutively without any additional stimulus applied. Then normalized against the 76dB result.
The tests are conducted in this fashion:
  1. 76dB at 1 meter (baseline; black)
  2. 86dB at 1 meter (red)
  3. 96dB at 1 meter (blue)
  4. 102dB at 1 meter (purple)
The purpose of this test is to illustrate how much (if at all) the output changes as a speaker’s components temperature increases (i.e., voice coils, crossover components) instantaneously.
JBL%20708P_Compression.png

Long Term Compression Tests
The below graphics indicate how much SPL is lost or gained in the long-term as a speaker plays at the same output level for 2 minutes, in intervals. Each graphic represents a different SPL: 86dB and 96dB both at 1 meter.
The purpose of this test is to illustrate how much (if at all) the output changes as a speaker’s components temperature increases (i.e., voice coils, crossover components).
The tests are conducted in this fashion:
  1. “Cold” logarithmic sine sweep (no stimulus applied beforehand)
  2. Multitone stimulus played at desired SPL/distance for 2 minutes; intended to represent music signal
  3. Interim logarithmic sine sweep (no stimulus applied beforehand) (Red in graphic)
  4. Multitone stimulus played at desired SPL/distance for 2 minutes; intended to represent music signal
  5. Final logarithmic sine sweep (no stimulus applied beforehand) (Blue in graphic)
The red and blue lines represent changes in the output compared to the initial “cold” test.
JBL%20708P_Long_Term_86_Compression.png
JBL%20708P_Long_Term_96_Compression.png




Parting / Random Thoughts
If you want to see the music I use for evaluating speakers subjectively, see my Spotify playlist.
  • Subjective listening varied between the nearfield at 1 meter and the midfield from 1-2 meters. Subjective listening was conducted at 80-95dB at these distances. Higher volumes were done simply to test the output capability in case one wants to try to sit further away. Since I only have one unit on hand for testing, listening was done in mono only (mixed stereo to mono through PC). Speaker was out in the open area of my living room, about 1 meter from the wall behind it and multiple meters from any other adjacent walls.
  • Higher Love - the bass is incredibly potent from a speaker this size. Looking at the data, the f10 shows as 35Hz and with this track containing such a thumping kickdrum it makes sense that what I heard translated so well with these speakers as even the f3 is below the 50-60Hz area of kickdrums. I did feel like the cymbal crash was missing just a touch of air. Looking at the data, maybe this is attributed to the 10kHz dip. Maybe it’s just my imagination.
  • Lauryn Hill’s “Doo Wop”… first “bookshelf” sized speaker I’ve had that can play this song at 90dB+ without exhibiting issues (mechanical or distortion/compression). I was sitting at 2 meters registering peaks of 105dB with average of 90dB. This is much higher than I would ever listen to for extended periods of time. And the clipping indicator would only occasionally flash. This passes my ‘stress test’ for a speaker of this type and use (bookshelf, nearfield/midfield) without issue and bests every other similar-sized speaker I have tested to date with this track.
  • In line with the output capability, the distortion even at 96dB @ 1m is within 1% THD above 100Hz and less than 3% below 100Hz.
  • Long-term compression testing is impeccable. At 86dB this speaker exhibits the ideal performance; no deviation from “cold” to even 4 minutes of continuous output of 86dB. And even at 96dB the difference is less than 0.10dB from cold to 4 minutes!
  • Tell Yer Mama - this track typically gives many speakers problems because it highlights cabinet resonance very well (it is one reason I use this track, other than just liking it). Listening to this on the 708P, however, made me go back to my trusty headphones to make sure I wasn’t missing something. There is no resonance. I have grown so accustomed to hearing resonance with various speakers that it actually threw me for a loop and prompted me to make a sanity check.
  • No audible hiss even when sitting right in front of the tweeter with the input sensitivity set to max.

All in all, I have zero issue recommending these speakers. They perform excellently (as they should at $3600/pair). The frequency response isn’t completely flat - though mostly within ±1.5dB - and exhibits a couple resonances at ~700Hz and 900Hz. However, these didn’t seem to be troublesome to me in my listening. It may be that the level is relatively low (~1dB above the mean) or maybe I am just not “tuned” for these frequencies as well as I am other issues. Aside from this, I do think the HF could use a single PEQ with a very wide Q at about 6.5kHz and knocked down about 0.5dB to take a little edge off.

Back to the price, I have to say that $3600/pair seems very steep. And I would expect to not see the resonances I mentioned. That said, with the built-in EQ, one could knock these down.

As stated in the Foreword, this written review is purposely a cliff’s notes version. For more details about the performance (objectively and subjectively) please watch the YouTube video.



Support / Donate

If you like what you see here and want to help me keep it going, please consider donating via the PayPal Contribute link here. Donations help me pay for new items to test, hardware, miscellaneous items and costs of the site’s server space and bandwidth. All of which I otherwise pay out of pocket. And, truthfully speaking, help me buy lunch and maybe take my wife and kid out for dinner now and again in an effort to “apologize” for spending so much time in the garage testing all these speakers. So, if you can help chip in a few bucks, know that it is very much appreciated. Alternatively, you can use the affiliate link on my site if you want to purchase these.

You can also join my Facebook and YouTube pages if you would like to follow along with updates.
 

richard12511

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MZKM

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Much lower score than I was expecting. We need a new score that incorporates this compression data ;). Both this and the DIY design do very well in that regard, but the Olive scores cares not.
One could make a dynamic ranking system for speakers Erin has measured in regards to compression. Not a scoring system though as no work has been done (have audiences compare identical speaker but one has an amp whose max wattage is limited).
 
Last edited:

napilopez

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Much lower score than I was expecting. We need a new score that incorporates this compression data ;). Both this and the DIY design do very well in that regard, but the Olive scores cares not.

Yeah,it's just directivity in this case. Speaker shows constant DI/flat PIR above 2K when the score wants to see a dip. All the points are lost in the SM_PIR, which continues to be the biggest issue with the preference formula aside from SPL-related things.

Edit: Well, mostly just directivity related. The speaker does have a slight overall rising response.
 
Last edited:

Maiky76

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This is copy/pasted from my website. Therefore, there may be some formatting things that go awry when pasted here. Feel free to view the review natively on my site linked below. Otherwise, enjoy it here!
https://www.erinsaudiocorner.com/loudspeakers/jbl_708p/

Yep, Amir measured this. Same exact one, actually. We do show some differences, mainly in the HF IIRC. I believe it was discovered that the speaker in Amir's test was angled a bit down or up... don't recall... and that likely explains the difference. It was discussed in another thread but I don't know where and I don't want to go dig it up. Maybe @MZKM remembers because it was his data that showed the error. Anyway....

JBL Professional 708P Bi-Amplified 8-Inch Master Reference Monitor
  • Sunday, May 23, 2021
DSC01944.JPG


Foreword / YouTube Video Review
The review on this website is a brief overview and summary of the objective performance of this speaker. It is not intended to be a deep dive. Moreso, this is information for those who prefer “just the facts” and prefer to have the data without the filler.
However, for those who want more - a detailed explanation of the objective performance, and my subjective evaluation (what I heard, what I liked, etc.) - please watch the below video where I go more in-depth.
<<coming soon>>


Information and Photos

The JBL 708P is a powered 2-way Studio Monitor featuring the JBL 728G 8-inch woofer and JBL 2409H compression driver in the JBL Image Control Waveguide. It features 1 x XLR-1/4” balanced combination analog audio input and 1 x XLR AES3 format digital input with 1 x XLR pass-through output. The following is from the manufacturer’s website:
JBL 708P is the self-powered reference monitor for critical music recording, film post and broadcast production applications. The 708P leverages new patent-pending driver technologies and JBL’s renowned Image Control Waveguide to deliver extraordinary output, stunning detail, an expansive soundstage, and greater accuracy in a broad range of rooms. 708P delivers several times the output of other comparably-sized studio monitors, providing significantly greater dynamic range and greater working distances. 708P features analog and digital inputs and sample rate converters. AES/EBU digital inputs allow connectivity with a broad range of production hardware, including digital audio workstations (DAW), mixing consoles and digital playback hardware with sample rates of up to 192 kHz.
MSRP is about $1800 USD for a single speaker.
DSC01943.JPG


DSC01948.JPG





CTA-2034 (SPINORAMA) and Accompanying Data
All data collected using Klippel’s Near-Field Scanner. The Near-Field-Scanner 3D (NFS) offers a fully automated acoustic measurement of direct sound radiated from the source under test. The radiated sound is determined in any desired distance and angle in the 3D space outside the scanning surface. Directivity, sound power, SPL response and many more key figures are obtained for any kind of loudspeaker and audio system in near field applications (e.g. studio monitors, mobile devices) as well as far field applications (e.g. professional audio systems). Utilizing a minimum of measurement points, a comprehensive data set is generated containing the loudspeaker’s high resolution, free field sound radiation in the near and far field. For a detailed explanation of how the NFS works and the science behind it, please watch the below discussion with designer Christian Bellmann:



The reference plane in this test is at tweeter per the manual.

Measurements are provided in a format in accordance with the Standard Method of Measurement for In-Home Loudspeakers (ANSI/CTA-2034-A R-2020). For more information, please see this link.

CTA-2034 / SPINORAMA:
CEA2034%20--%20JBL%20708P.png


Early Reflections Breakout:
Early%20Reflections.png


Estimated In-Room Response:
Estimated%20In-Room%20Response.png


Horizontal Frequency Response (0° to ±90°):
SPL%20Horizontal.png


Vertical Frequency Response (0° to ±40°):
SPL%20Vertical.png


Horizontal Contour Plot (not normalized):
JBL%20708P_Horizontal_Spectrogram_Full.png


Horizontal Contour Plot (normalized):
JBL%20708P%20Beamwidth_Horizontal.png


Vertical Contour Plot (not normalized):
JBL%20708P_Vertical_Spectrogram_Full.png


Vertical Contour Plot (normalized):
JBL%20708P%20Beamwidth_Vertical.png




Additional Measurements

On-Axis Response Linearity
JBL%20708P%20FR_Linearity.png

“Globe” Plots
These plots are generated from exporting the Klippel data to text files. I then process that data with my own MATLAB script to provide what you see. These are not part of any software packages and are unique to my tests.
Horizontal Polar (Globe) Plot:
This represents the sound field at 2 meters - above 200Hz - per the legend in the upper left.
JBL%20708P_360_Horizontal_Polar.png



Vertical Polar (Globe) Plot:
This represents the sound field at 2 meters - above 200Hz - per the legend in the upper left.
JBL%20708P_360_Vertical_Polar.png



Harmonic Distortion
Harmonic Distortion at 86dB @ 1m:
JBL%20708P%20--%20Harmonic%20Distortion%2086dB%20%40%201m.png


Harmonic Distortion at 96dB @ 1m:
JBL%20708P%20--%20Harmonic%20Distortion%2096dB%20%40%201m.png


Dynamic Range (Instantaneous Compression Test)
The below graphic indicates just how much SPL is lost (compression) or gained (enhancement; usually due to distortion) when the speaker is played at higher output volumes instantly via a 2.7 second logarithmic sine sweep referenced to 76dB at 1 meter. The signals are played consecutively without any additional stimulus applied. Then normalized against the 76dB result.
The tests are conducted in this fashion:
  1. 76dB at 1 meter (baseline; black)
  2. 86dB at 1 meter (red)
  3. 96dB at 1 meter (blue)
  4. 102dB at 1 meter (purple)
The purpose of this test is to illustrate how much (if at all) the output changes as a speaker’s components temperature increases (i.e., voice coils, crossover components) instantaneously.
JBL%20708P_Compression.png


Long Term Compression Tests
The below graphics indicate how much SPL is lost or gained in the long-term as a speaker plays at the same output level for 2 minutes, in intervals. Each graphic represents a different SPL: 86dB and 96dB both at 1 meter.
The purpose of this test is to illustrate how much (if at all) the output changes as a speaker’s components temperature increases (i.e., voice coils, crossover components).
The tests are conducted in this fashion:
  1. “Cold” logarithmic sine sweep (no stimulus applied beforehand)
  2. Multitone stimulus played at desired SPL/distance for 2 minutes; intended to represent music signal
  3. Interim logarithmic sine sweep (no stimulus applied beforehand) (Red in graphic)
  4. Multitone stimulus played at desired SPL/distance for 2 minutes; intended to represent music signal
  5. Final logarithmic sine sweep (no stimulus applied beforehand) (Blue in graphic)
The red and blue lines represent changes in the output compared to the initial “cold” test.
JBL%20708P_Long_Term_86_Compression.png

JBL%20708P_Long_Term_96_Compression.png





Parting / Random Thoughts
If you want to see the music I use for evaluating speakers subjectively, see my Spotify playlist.
  • Subjective listening varied between the nearfield at 1 meter and the midfield from 1-2 meters. Subjective listening was conducted at 80-95dB at these distances. Higher volumes were done simply to test the output capability in case one wants to try to sit further away. Since I only have one unit on hand for testing, listening was done in mono only (mixed stereo to mono through PC). Speaker was out in the open area of my living room, about 1 meter from the wall behind it and multiple meters from any other adjacent walls.
  • Higher Love - the bass is incredibly potent from a speaker this size. Looking at the data, the f10 shows as 35Hz and with this track containing such a thumping kickdrum it makes sense that what I heard translated so well with these speakers as even the f3 is below the 50-60Hz area of kickdrums. I did feel like the cymbal crash was missing just a touch of air. Looking at the data, maybe this is attributed to the 10kHz dip. Maybe it’s just my imagination.
  • Lauryn Hill’s “Doo Wop”… first “bookshelf” sized speaker I’ve had that can play this song at 90dB+ without exhibiting issues (mechanical or distortion/compression). I was sitting at 2 meters registering peaks of 105dB with average of 90dB. This is much higher than I would ever listen to for extended periods of time. And the clipping indicator would only occasionally flash. This passes my ‘stress test’ for a speaker of this type and use (bookshelf, nearfield/midfield) without issue and bests every other similar-sized speaker I have tested to date with this track.
  • In line with the output capability, the distortion even at 96dB @ 1m is within 1% THD above 100Hz and less than 3% below 100Hz.
  • Long-term compression testing is impeccable. At 86dB this speaker exhibits the ideal performance; no deviation from “cold” to even 4 minutes of continuous output of 86dB. And even at 96dB the difference is less than 0.10dB from cold to 4 minutes!
  • Tell Yer Mama - this track typically gives many speakers problems because it highlights cabinet resonance very well (it is one reason I use this track, other than just liking it). Listening to this on the 708P, however, made me go back to my trusty headphones to make sure I wasn’t missing something. There is no resonance. I have grown so accustomed to hearing resonance with various speakers that it actually threw me for a loop and prompted me to make a sanity check.
  • No audible hiss even when sitting right in front of the tweeter with the input sensitivity set to max.

All in all, I have zero issue recommending these speakers. They perform excellently (as they should at $3600/pair). The frequency response isn’t completely flat - though mostly within ±1.5dB - and exhibits a couple resonances at ~700Hz and 900Hz. However, these didn’t seem to be troublesome to me in my listening. It may be that the level is relatively low (~1dB above the mean) or maybe I am just not “tuned” for these frequencies as well as I am other issues. Aside from this, I do think the HF could use a single PEQ with a very wide Q at about 6.5kHz and knocked down about 0.5dB to take a little edge off.

Back to the price, I have to say that $3600/pair seems very steep. And I would expect to not see the resonances I mentioned. That said, with the built-in EQ, one could knock these down.

As stated in the Foreword, this written review is purposely a cliff’s notes version. For more details about the performance (objectively and subjectively) please watch the YouTube video.



Support / Donate

If you like what you see here and want to help me keep it going, please consider donating via the PayPal Contribute link here. Donations help me pay for new items to test, hardware, miscellaneous items and costs of the site’s server space and bandwidth. All of which I otherwise pay out of pocket. And, truthfully speaking, help me buy lunch and maybe take my wife and kid out for dinner now and again in an effort to “apologize” for spending so much time in the garage testing all these speakers. So, if you can help chip in a few bucks, know that it is very much appreciated. Alternatively, you can use the affiliate link on my site if you want to purchase these.

You can also join my Facebook and YouTube pages if you would like to follow along with updates.

Hi,

Here is my take on the EQ.
The raw data with corrected ER and PIR:

Score no EQ: 4.9
With Sub: 6.7

Spinorama with no EQ:
  • Quite few resonances
  • Great horizontal directivity
JBL 708P No EQ Spinorama.png


Directivity:

Better stay at tweeter height
Horizontally, better toe-in the speakers by 10/20deg and have the axis crossing in front of the listening location, might help dosing the upper range.
JBL 708P 2D surface Directivity Contour Only Data.png


JBL 708P LW Better data.png


EQ design:

I have generated One EQs. The APO config file is attached.
  • The LW and Score EQ are for intent and purpose identical (wave guide)
  • Quite a bit of work
Score EQ : 6.5
with sub: 8.2

Code:
JBL 708P APO EQ LW-Score 96000Hz
May242021-112640

Preamp: -1 dB

Filter 1: ON HPQ Fc 35.5 Hz Gain 0 dB Q 1.23
Filter 2: ON PK Fc 64 Hz Gain -1.55 dB Q 0.88
Filter 3: ON PK Fc 104 Hz Gain -1.18 dB Q 0.39
Filter 4: ON PK Fc 627.6 Hz Gain 1.5 dB Q 1.74
Filter 5: ON PK Fc 672.6 Hz Gain -2.4 dB Q 10.7
Filter 6: ON PK Fc 912 Hz Gain -2.79 dB Q 5.15
Filter 7: ON PK Fc 1308 Hz Gain 1 dB Q 2.5
Filter 8: ON PK Fc 3580 Hz Gain -1.37 dB Q 3.66
Filter 9: ON PK Fc 5209 Hz Gain -0.83 dB Q 6.78
Filter 10: ON PK Fc 7101 Hz Gain -1.8 dB Q 2.6
Filter 11: ON PK Fc 13792 Hz Gain -3.46 dB Q 3.6

JBL 708P EQ Design.png


Spinorama EQ
JBL 708P EQ Spinorama.png


Zoom PIR-LW-ON
JBL 708P Zoom.png


Regression - Tonal
JBL 708P Regression - Tonal.png


Radar no EQ vs EQ score
Nice improvements
JBL 708P Radar.png


The rest of the plots is attached.
 

Attachments

  • JBL 708P APO EQ LW-Score 96000Hz.txt
    581 bytes · Views: 22
  • JBL 708P Vertical 3D Directivity data.png
    JBL 708P Vertical 3D Directivity data.png
    601.5 KB · Views: 25
  • JBL 708P Horizontal 3D Directivity data.png
    JBL 708P Horizontal 3D Directivity data.png
    588.4 KB · Views: 18
  • JBL 708P Normalized Directivity data.png
    JBL 708P Normalized Directivity data.png
    463.9 KB · Views: 17
  • JBL 708P Raw Directivity data.png
    JBL 708P Raw Directivity data.png
    797.3 KB · Views: 21
  • JBL 708P Reflexion data.png
    JBL 708P Reflexion data.png
    253 KB · Views: 24
  • JBL 708P LW data.png
    JBL 708P LW data.png
    257.3 KB · Views: 29
  • JBL 708P 2D surface Directivity Contour Data.png
    JBL 708P 2D surface Directivity Contour Data.png
    286.9 KB · Views: 24
  • JBL 708P 3D surface Vertical Directivity Data.png
    JBL 708P 3D surface Vertical Directivity Data.png
    449.1 KB · Views: 26
  • JBL 708P 3D surface Horizontal Directivity Data.png
    JBL 708P 3D surface Horizontal Directivity Data.png
    437.2 KB · Views: 22

MZKM

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Erin, could you try to indulge me and try find the minimum distance for far-field conditions of this speaker?

My understanding is:
Look at the Radiated Sound Power graph and see at what frequency the monopole nature (N=0) is most reduced, likely around the crossover frequency (but could be around port tuning).
Then look at the Apparent Sound Power for that frequency, see at what distance Total Power becomes 0.5dB away from monopole (N=0).
 
Last edited:
OP
hardisj

hardisj

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The Youtube video seems to be MIA.
That's because Erin releases the spinorama before he makes a video review.
I'm guessing the link is a placeholder.

Yep. @sweetchaos got it. I rarely release the video first. In some cases I release the reviews at the same time. Most of the time, however, I release the data first. I do this for a few reasons:
1) Time. I figure people want to see the data and I don't want to sit on the data for a week while I wait until I have the time to make the video.
2) Feedback. It helps to put the data out there and get some feedback/questions about it that I hadn't considered and then I can address it in my video.

Hopefully I'll have the video up this week. I've got three to make. Along with a few DIYSG speakers to measure (1099 towers and center, volt-6 and volt-8).

And, yet, I still manage to find time to do the dishes and fold the laundry even with a regular full-time job. :D :D :D lol

#nosleep
 
OP
hardisj

hardisj

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Erin, could you try to indulge me and try find the minimum distance for far-field conditions of this speaker?

My understanding is:
Look at the Radiated Sound Power graph and see at what frequency the monopole nature (N=0) is most reduced, likely around the crossover frequency (but could be around port tuning).
Then look at the Apparent Sound Power for that frequency, see at what distance Total Power becomes 0.5dB away from monopole (N=0).

I'll need to go back and watch my interview with Christian again to see if that's the correct interpretation. If I have time for that - not that I will - then yes, I'll see if I can find the minimum distance.

I also have another way of doing this, I think, but I'll reserve that method for later. :)
 

Jim Matthews

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This speaker and early discussions of it drew me to ASR.

Not mentioned in the review is that the internal amplification has no "character" or identifiable noise profile. The only way I can tell they're on without music playing is the status LED on the front.
 
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hardisj

hardisj

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Not mentioned in the review is that the internal amplification has no "character" or identifiable noise profile.

That is precisely why it wasn't mentioned in the video.


Though, I did mention it in the written review:
No audible hiss even when sitting right in front of the tweeter with the input sensitivity set to max.
 

io53

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Thanks for another review!
I noticed that the first graphs are done at 85db, while the fives was done at ~96db, 305p at 92db.
Is there any reason for that? Maybe it does not make sense for bigger speakers, but for small speakers, especially with DSP that could affect the response quite a bit.
 
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MZKM

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Thanks for another review!
I noticed that the first graphs are done at 85db, while the fives was done at ~96db, 305p at 92db.
Is there any reason for that? Maybe it does not make sense for bigger speakers, but for small speakers, especially with DSP that could affect the response quite a bit.
Unless Erin compensates for it, the NFS doesn’t record the actual SPL of powered speakers, as I guess it doesn’t know the gain of their amplifiers. Amir notes this in his more recent powered speaker reviews.
 
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hardisj

hardisj

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Yep.

With passive speakers, you set it up for 2.83v input and go. That's it.

But active speakers are a different animal. The real issue is this: how do you know that ndB isn't too high? Speakers are linear until they aren't. As you can see in my compression testing with other speakers of late, you could be in the non-linear range of FR even in the mid-80's SPL. What do you do? Well, you use engineering judgement, make sure you aren't clipping inputs and provide the best data you can with the experience and said judgement. Per the CTA-2034 spec (quoted below), I usually shoot for around 80dB at 2m (equivalent) or lower, as long as I can keep the SNR low (using 4x averaging helps with this). I spend a fair bit of time, sometimes, fiddling with the "volume knob" on them to get the correct ratio of input/output voltage through the system to the actual speakers themselves (on the out end of the built-in amplifier). It's a balancing act.



1622431765137.png



After all of this testing, my Klippel script is set to provide output SPL referenced to 0.30v.
 
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