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IK Multimedia iLoud Precision MTM Spinorama

abdo123

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How, please explain?

The Genelecs 8351B uses the MTM cancellations to effectively increase its vertical directivity.

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Please explain how you compare this speaker’s off-axis and band limited dip to Genelec One series?

I didn't mean to do a direct comparison. just that when designed properly it is quite effective. the post right above mine shows that there is a fairly decent amount of control in the vertical radiation. Narrow, but controlled.
There’s no such thing as insensitivity to vertical directivity. Any off-axis FR irregularity will affect the FR in the room. Just look at any speaker tested on ASR. Maybe you can show us another speaker that has a 40dB lope, which is “fine”? If you think in the near field that’s not the case, look at the studio picture I posted above: How will the reflection FR from the desk surface will be when there’s a 40dB lope in the FR?

It is very very common knowledge that we're much less sensitive to vertical directivity, it is why every 2-way design out there is usually placed with the tweeter facing up or down but never with the speaker on its sides.

Even all of Harman's preference research heavily favors horizontal directivity. For example, Listening window only includes +/- 10 degrees vertically, while horizontally it includes +/- 10, 20 and 30 degrees. For Early Reflections it gets even more interesting, we get +/- 90 degrees horizontally, and 40 degrees below the tweeter and 60 degrees above it. No idea why there is a mismatch there, you're the expert here so maybe you have an idea?

As for ''Speakers with 40 dB nulls'' being fine. Here is the Genelec S360 vertical directivity showing a very sharp -20 db null. I could probably find a worse example with something like the JBL M2 with an even larger mismatch (big horn + big woofer) but I will leave that for you incase you're curious. Honestly for me -20dB is just as bad acoustically as -40 dB.

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sarumbear

sarumbear

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The Genelecs 8351B uses the MTM cancellations to effectively increase its vertical directivity.
It is a 3-way speaker, what is MTM about it?

I could probably find a worse example with something like the JBL M2 with an even larger mismatch (big horn + big woofer) but I will leave that for you incase you're curious.
Where do you see a similar dip in the JBL M2?

Honestly for me -20dB is just as bad acoustically as -40 dB.
I agree with you that 20dB is pretty bad. However, I will not call such speakers as "fine" either. They are simply bad designs. Smooth spinorama can be done and was achieved a long time ago. I have a pair at home. Size, nor number of drivers is not a major limitation either.
 

TimW

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I have a pair of MTM speakers that sound very good to me. Here is the Vertical Directivity showing a 40+dB dip at 30 degrees off axis:
1672181012746.png


And here is the Spinorama which looks much better:
CEA2034.jpg


If I stand near the speakers there is a clear suck-out in mid frequencies but at all of my seating positions it sounds just fine. In fact it sounds better to me than my tweeter-mid JBL Studio 530s or the coaxial KEF LS50s I owned. I listened to all three speakers using EQ based on Klippel data along with subwoofers and room EQ. I just don't hear the vertical directivity issue, or if I do It doesn't bother me.
 

Berwhale

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It is a 3-way speaker, what is MTM about it?

Twin bass drivers above and below the co-axial midrange and treble drivers...

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AnalogSteph

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That's more of a WCW, or WMTW if you insist. Making it a 3-way means that the woofers can be crossed over low enough to eliminate the issues that make MTMs so problematic (320 Hz in this case), and average distance is further reduced by making the woofers a racetrack design. With the hidden slot-firing woofers, they could also eliminate all kinds of protrusions on the baffle and thus the associated diffraction effects. Very smart design. It goes without saying that for full benefits they should ideally be mounted suspended in thin air or something not very far from it anyway (e.g. hanging on a treated wall), well clear of any obstacles to the sides.
 

abdo123

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It is a 3-way speaker, what is MTM about it?


Where do you see a similar dip in the JBL M2?


I agree with you that 20dB is pretty bad. However, I will not call such speakers as "fine" either. They are simply bad designs. Smooth spinorama can be done and was achieved a long time ago. I have a pair at home. Size, nor number of drivers is not a major limitation either.

There seem to be a misunderstanding, every speaker on this earth will have these dips except for point source designs.

1672211029509.png
 
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thewas

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There seem to be a misunderstanding, every speaker on this earth will have these dips except for point source designs.
Yes, even his own designed Silver 5L. On the other hand vertical dips are not luckily usually not very audible, especially when the crossover has high slopes which results in narrow off-axis slopes. Personally though I prefer point source designs especially for nearfield/desktop monitoring also due to the console/table reflection.
 
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sarumbear

sarumbear

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Twin bass drivers above and below the co-axial midrange and treble drivers...

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The bass drivers cut off at 490Hz which has a wavelength of 70cm? There’s no geometric impact on the FR with the positioning of the drivers like with a MTM layout.
 
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sarumbear

sarumbear

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Yes, even his own designed Silver 5L.
I guess so though vertical dispersion was never measured. The crossover is LR 4th order.

On the other hand vertical dips are not luckily usually not very audible, especially when the crossover has high slopes which results in narrow off-axis slopes.
I agree. You see the narrow dip in Erin’s graph because he didn’t seem to apply proper smoothing. If you look at Harman’s chart you won’t see that dip.

In Erin’s graph the dip of M2 is 50Hz (1/12 octave) wide at -20dB and 200Hz (1/3 octave) wide at -10dB.

Whereas the dip of this speaker is 500Hz (1/2 octave) wide at -20dB and a huge 2200Hz (2+ octaves) wide at -10dB.

If you cannot understand the importance of the difference I pointed you above then I failed and shouldn’t continue further.
 

thewas

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I agree. You see the narrow dip in Erin’s graph because he didn’t seem to apply proper smoothing. If you look at Harman’s chart you won’t see that dip.

In Erin’s graph the dip of M2 is 50Hz (1/12 octave) wide at -20dB and 200Hz (1/3 octave) wide at -10dB.

Whereas the dip of this speaker is 500Hz (1/2 octave) wide at -20dB and a huge 2200Hz (2+ octaves) wide at -10dB.

If you cannot understand the importance of the difference I pointed you above then I failed and shouldn’t continue further.
You are confusing me with someone else (guess for Abdo123?) as this was my first and only post/comment in this thread.
 
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sarumbear

sarumbear

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You are confusing me with someone else (guess for Abdo123?) as this was my first and only post/comment in this thread.
I was replying to your post though, haven’t I?
 

thewas

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I was replying to your post though, haven’t I?
You wrote though "I pointed you above" which doesn't make sense, also my post wasn't in contradiction to what you replied to me as I had written that the width of the dip is important.
 
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sarumbear

sarumbear

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You wrote though "I pointed you above" which doesn't make sense, also my post wasn't in contradiction to what you replied to me as I had written that the width of the dip is important.
Then we are in agreement aren’t we? You has two modes, singular and plural :)
 

thewas

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Then we are in agreement aren’t we? You has two modes, singular and plural :)
Why do write your reply than trying to correct me on something I didn't write and claiming that I am the one who didn't understand? Not a nice style.
 
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sarumbear

sarumbear

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Why do write your reply than trying to correct me on something I didn't write and claiming that I am the one who didn't understand? Not a nice style.
I’m sorry if that’s how you interpreted my words. It was not intentional. I was replying to you and the members in general on the same post. I did say that I agree…
 

napilopez

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Sorry to be pedantic, but with all due respect those handful of measurements aren't a spinorama @sarumbear. I would just call the thread "iloud measurements" since I was expeting something a bit more thorough =]. It takes 72 angles processed in a particular way, not just 3. One can't just look at an on-axis graph a couple of vertical off-axis points and make a reliable prediction of the in-room sound from that -- only the direct sound at those specific angles.

As others have mentioned, these vertical dips are common for any non-point-source speakers. It's just that most readers don't look so closely at the vertical data so closely around these parts. For some more context, here's the lobing of some good-performing speakers on ASR. (Revel M106 in Red, Revel F328Be in Blue, Focal Solo6 Be in Yellow, Genelec 8030C in Purple).

iLoud precision lobing comparison.png


All that being said, I do think the width and depth of the dip measured by soundonsound for the iLoud Precision looks particularly bad. Here it is plotted against the above speakers at the same scale for comparison:

iLoud compared.png


However, I wouldn't draw too much of a conclusion from a measurement source that hasn't been compared to the typical NFS and anechoic standard, nor would I make broader conclusions about in-room sound from so few angles measured.

On some speakers I've measured, the vertical dip remains present over a wide range of vertical angles, on others the lobing is only found at a few specific angles. On some speakers, the lobing balances out somewhat over a wide frequency range over multiple angles, on others it's concentrated at a specific frequency. Anecdotally, most harman speakers show some big lobing, but it's usually concentrated to a handful of angles and narrow range of frequencies (especially on JBL horns). The Focal Solo6 Be above on the other hand, has that lobe stretched out over a wide variety of angles.

Moreover, I would argue that nearfield studio speakers are indeed less sensitive to vertical issues than typical home speakers (aside from initial positioning). The closer you are to a speaker, the less effect the off-axis sounds have on you because reflections will be quieter relative to the direct sound. This is evident in the measured in-room response as the further you are from the speaker, the less the graph looks like in the on-axis, and the more it looks like the predicted-in-room response of the spinorama.

All this is to say the Precision MTM's lobing could be a big audible issue, or it might not be that big of a deal. We'd really have to see more data on it.
 
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sarumbear

sarumbear

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All that being said, I do think the width and depth of the dip measured by soundonsound for the iLoud Precision looks particularly bad. Here it is plotted against the above speakers at the same scale for comparison:

View attachment 253015
All I can say is thank you for your work that shows the point I was trying to make clearly. Whether anyone can live with such an anomaly or not is the buyers decision. I was only pointing out to the anomaly, which you clearly displayed.

Comparing different test results are indeed problematic but when there’s such a huge anomaly can you ignore what you see? Especially when the reviewer has mentioned the expected audible result.
 

Spocko

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Below are the measurements before and after using iLoud's ARC 3 software with photos of my room. Green is before, Orange is after (in the X-Monitor image: #1 is left speaker, #2 is right speaker).
Notice the HUGE dip between 90Hz and 120Hz for both speakers. Although both speakers are only 8" from the front wall, the right speaker is only 24" from the right wall but the left speaker is near the center of the room which creates huge broad spikes between 100Hz and 7KHz. The room correction DEFINITELY minimized my left speaker issues whereas the right speaker only needed the to have corrections done below 500Hz.

Screenshot 2023-03-08 at 9.05.55 AM.png
Screenshot 2023-03-08 at 9.05.43 AM.png



And you can customize the post-calibration corrections

Screenshot 2023-03-08 at 9.56.49 AM.png

I also included images of my room (10'L x 9'W x 9'H) and the speaker placement relative to MLP (foam base is to point them 5 degrees downward)

room1.png



Notice behind me is a large GIK Monster Bass Trap (24" x 48" x 7" thick) next to the giant wood panel scatter plate, and to my right is GIK Polyfusor absorber/diffuser. Since my room is so small, I have to control echo and other direct reflections above 400Hz. I still need to add nice thick 6' x 6' carpeting because I'm also recording my voiceovers and talking head videos in this room (it actually sounds pretty good already, but there's always room to tighten up my voice resonances!).

room2.png
 
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Spocko

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Below are the measurements before and after using iLoud's ARC 3 software with photos of my room. Green is before, Orange is after. #1 is left speaker, #2 is right speaker.
Notice the HUGE dip between 90Hz and 120Hz for both speakers. Although both speakers are only 8" from the front wall, the right speaker is only 24" from the right wall but the left speaker is near the center of the room which creates huge broad spikes between 100Hz and 7KHz. The room correction DEFINITELY minimized my left speaker issues whereas the right speaker only needed the to have corrections done below 500Hz.

View attachment 270277View attachment 270279



I also included images of my room (10'L x 9'W x 9'H) and the speaker placement relative to MLP (foam base is to point them 5 degrees downward)

View attachment 270281


Notice behind me is a large GIK Monster Bass Trap (24" x 48" x 7" thick) and giant wood panel scatter plate, and to my right is GIK Polyfusor absorber/diffuser. Since my room is so small, I have to control echo and other direct reflections above 400Hz. I still need to add nice thick 6' x 6' carpeting because I'm also recording my voiceovers and talking head videos in this room (it actually sounds pretty good already, but there's always room to tighten things up my voice resonances!).

View attachment 270282
Quick commentary to the measurements I posted: my room has such a BIG effect on speaker performance such that I can't imagine reviewing any speaker in my room fairly without effective DSP to minimize room interaction but then ultimately it's the review of the hardware/software package. So ultimately, speakers designed to be used with DSP correction needs to be reviewed with that context in mind. Personally, I just love this DSP because as I click on different EQ settings, you can hear the changes instantly and quickly choose the frequency you want emphasized on the fly - this level of convenience for mixing/mastering is invaluable.
 
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