M2 waveguided system

Hello,

I'm looking into moving to a M2 waveguide for my 2452sl driver and came across this thread on doing similar.

http://www.audioheritage.org/vbullet...monitor/page11

The members inbox is full, so I cannot ask advice on it.

I noticed he put the crossover point for the compression driver at 540hz and the bass driver at 800hz. I was surprised it was so low for the M2 waveguide!

Can you offer any advice opinions on crossing to either a 2226, 2265 or AETD10m+ 2242 as a 3 way?

It's an in wall flush mounted system

Thanks.

Are you going passive or active?? I used the M2 with a 476Mg same driver family and crossed at 700Hz to the M2 waveguide. Have you taken measurements with your drivers??

Rob:)

Quote:

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Originally Posted by lbstyling

Hello,

I'm looking into moving to a M2 waveguide for my 2452sl driver and came across this thread on doing similar.

http://www.audioheritage.org/vbullet...monitor/page11

The members inbox is full, so I cannot ask advice on it.

I noticed he put the crossover point for the compression driver at 540hz and the bass driver at 800hz. I was surprised it was so low for the M2 waveguide!

Can you offer any advice opinions on crossing to either a 2226, 2265 or AETD10m+ 2242 as a 3 way?

It's an in wall flush mounted system

Thanks.

---

Hi lbstyling,

As can be seen from the mentioned link, it can be concluded that the horn loading under say 1300Hz is not so good, so I can suggest You to to use something round that frequency as crossover frequency for the mentioned driver connected to the M2 horn.
2226Nd can be used as a very good "low mid-bass" driver, but concerning to its size, a problem of its higher frequencies (say over 800Hz) dispersion. Some tricks have been applied on some JBL pro boxes ( JBL EON 615 Woofer Cover Plate 5039904 )

https://reconingspeakers.com/product/jbl-eon-615-woofer-cover-plate-5039904/

in order to improve 2226Nd dispersion of the higher frequencies.
A kind of lower bass driver such as 18" driver (2269, 2245, 2242...) , I think, would be welcome. Crossover round 250Hz, I think would be quite acceptable (such as 4345, as an example).

Regards Ivica

Quote:

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Originally Posted by Robh3606

Are you going passive or active?? I used the M2 with a 476Mg same driver family and crossed at 700Hz to the M2 waveguide. Have you taken measurements with your drivers??

Rob:)

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Active -Hypex NCore 3 way plate amps.

I have taken measurements with my driver's in a JMLC 350hz horn, not that that helps much!

Speaker width can be quite wide for me 800/900 mm is ok, so I looked at the 2384 horn, but it is not as CD as the M2. Price is similar.

Ivica, I did not know the woofer plates were available to buy! I assume they trade off distortion for pattern matching the bass driver to the horn... If they are cheap, it's worth a go!

Quote:

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Originally Posted by lbstyling

Active -Hypex NCore 3 way plate amps.

I have taken measurements with my driver's in a JMLC 350hz horn, not that that helps much!

Speaker width can be quite wide for me 800/900 mm is ok, so I looked at the 2384 horn, but it is not as CD as the M2. Price is similar.

Ivica, I did not know the woofer plates were available to buy! I assume they trade off distortion for pattern matching the bass driver to the horn... If they are cheap, it's worth a go!

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slot defusers can be used on all sorts of drivers. The BBC used slot defusers on some of their in house designed studio monitors. Depending on the shape and size they can alter dispersion. If taken too far it's possible to introduce coloration to the sound. Try cupping your hands around your mouth at different distances while speaking to hear the effect.

Quote:

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Originally Posted by Epplerd

slot defusers can be used on all sorts of drivers. The BBC used slot defusers on some of their in house designed studio monitors. Depending on the shape and size they can alter dispersion. If taken too far it's possible to introduce coloration to the sound. Try cupping your hands around your mouth at different distances while speaking to hear the effect.

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I suppose the thing I'm concerned about is that they didn't use it on the M2, so what are the trade offs? I'm guessing distortion through turbulence.

The bass driver used in the M2 is expensive and rather special I understand. I assume it has a particularly high breakup frequency, giving me pause to check the 2226 is appropriate.

I have a pair of AE TD10m (10inch) drivers that I could use, and a pair of 2206h 12 inch ones. The 2206 drivers have been reconed with what I assume is not OEM JBL cones, so I'm hesitant on this also.

Obviously the SPL for these is limited compared to a 15 inch, but the TD10m in particular can go very high in frequency cleanly. If the M2 horn is limited to above 800hz, the question is will we have a reasonable pattern match between a TD10m and the M2 horn.

The M2 horn has a pattern width of about 110 degrees, but I don't know how much this is lost at 800hz and below. I guess JBL may have relied on the beaming of a 15 inch driver as a feature to match the pattern of the horn?

Quote:

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Originally Posted by Robh3606

Are you going passive or active?? I used the M2 with a 476Mg same driver family and crossed at 700Hz to the M2 waveguide. Have you taken measurements with your drivers??

Rob:)

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How steep did you go with the crossover? And what driver did you crossover to?

Quote:

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Originally Posted by lbstyling

I suppose the thing I'm concerned about is that they didn't use it on the M2, so what are the trade offs? I'm guessing distortion through turbulence.

The bass driver used in the M2 is expensive and rather special I understand. I assume it has a particularly high breakup frequency, giving me pause to check the 2226 is appropriate.

I have a pair of AE TD10m (10inch) drivers that I could use, and a pair of 2206h 12 inch ones. The 2206 drivers have been reconed with what I assume is not OEM JBL cones, so I'm hesitant on this also.

Obviously the SPL for these is limited compared to a 15 inch, but the TD10m in particular can go very high in frequency cleanly. If the M2 horn is limited to above 800hz, the question is will we have a reasonable pattern match between a TD10m and the M2 horn.

The M2 horn has a pattern width of about 110 degrees, but I don't know how much this is lost at 800hz and below. I guess JBL may have relied on the beaming of a 15 inch driver as a feature to match the pattern of the horn?

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The diameter of a transducer will determine the frequency at which it becomes more and more directional. Depending on the design of the transducer it also might be suffering from breakup before or after it becomes directional. If you are able to match the directivity patterns of the drivers at the crossover point, you also need to take into account their acoustic centres, ( which can vary with frequency). If the acoustic centres are aligned at the crossover frequency, the in phase sum of the drivers should be on axis . If not the axis can tilt up or down. For example JBL 4430 tilted the axis slightly above the horizontal. It's a complex subject requiring knowledge and the requisite test equipment to achieve the desired results.

Quote:

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Originally Posted by lbstyling

How steep did you go with the crossover? And what driver did you crossover to?

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18db electrical on both the high and low pass. Using a 2216Nd and 476Mg CD.

Rob:)