Project M2 DIY Thread

[Aaron]

The more I think about it, the more I have to say...there are just so many seemingly small but important tools & techniques!

...I'll start a build thread and go over pretty much everything, that oughta keep me out of trouble.

[Flodstroem]

The more I think about it, the more I have to say...there are just so many seemingly small but important tools & techniques!

...I'll start a build thread and go over pretty much everything, that oughta keep me out of trouble.

Sound very interesting. Im looking forward to your building thread Aaron

[globulegl]

What is the difference between d2430h and d2430k. Lower frequency response for the 2430k?

[srm51555]

So I finally had time to try out the 2450SL-be's on my build and feel they are better suited for my needs. The D2430K's sounded very nice in a bigger room my house, but this room is doing kid duty for the next 18 years and I was never quite able to get the EQ'ing correct on them in my smaller listening room. Also I don't really need the spl capabilities of the D2430K's.Having a $1200 set of diaphragms sitting around doing nothing also played into it.


I'm now to the point of my audio journey where I feel like I have reached the peak of sound vs affordability and have no clue what to do with my audio need but here are some of my thoughts:

1) Sell all unused equipment, Wish I did this before my Mcintosh mc2155 went on the fritz this week. Sending it in for repairs this week hopefully. I'll keep this amp after complete rebuild and hopefully it will last another 10 years.
2) Purchase another set of woofers and be diaphragms for backups.

I also have some thoughts about using the extra set 2216nd's as under 100hz fillers. Although I don't think it needs it but it could be fun to play around with.

My lightly used D2430K's will be for sale if anyone is interested, shoot over a PM.

Thanks,
Scott

[hsosdrum]

I'm now to the point of my audio journey where I feel like I have reached the peak of sound vs affordability and have no clue what to do with my audio need ...

Just sit back and enjoy the music.

[pos]

Hello Scott,

How would you describe the difference between the D2 and 4" Be ?
How did you EQ them? Did you look for an identical response curve between the two?

I also have some thoughts about using the extra set 2216nd's as under 100hz fillers. Although I don't think it needs it but it could be fun to play around with.

This could help with room modes, at least.
Integrating a helper woofer in the M2 design is pretty straightforward if using an identical volume/tuning (~280L total!):

1. change the LF shelving to -2dB instead of -8dB
2. increase the Q/slope of that shelving a bit (IIRC in rephase I had to go from 0.6 to just under 1.0 when doing the simulation)
3. lower gain by 6dB
4. duplicate these LF settings for the helper woofer
5. add a 1st order low pass at 95.5Hz for that helper woofer ( 135Hz/sqrt(2) )

Steps 4 and 5 could probably be replaced by a line-level passive 1st order filter in front of the amplifier for the helper woofer, in order to save a DSP channel (unless you are using crown amps with integrated DSPs that is...)

[srm51555]

Just sit back and enjoy the music.

This is the toughest part, I really enjoy both the music and the equipment side of it.

Hello Scott,

How would you describe the difference between the D2 and 4" Be ?
How did you EQ them? Did you look for an identical response curve between the two?


This could help with room modes, at least.
Integrating a helper woofer in the M2 design is pretty straightforward if using an identical volume/tuning (~280L total!):

1. change the LF shelving to -2dB instead of -8dB
2. increase the Q/slope of that shelving a bit (IIRC in rephase I had to go from 0.6 to just under 1.0 when doing the simulation)
3. lower gain by 6dB
4. duplicate these LF settings for the helper woofer
5. add a 1st order low pass at 95.5Hz for that helper woofer ( 135Hz/sqrt(2) )

Steps 4 and 5 could probably be replaced by a line-level passive 1st order filter in front of the amplifier for the helper woofer, in order to save a DSP channel (unless you are using crown amps with integrated DSPs that is...)

Thanks for the integration notes, I like having the idea of having the extra woofers in a separate box for easier room placement. I'm sure when I get them we will talk further.

As for the difference between the two drivers, I felt the stock M2 is more of a studio tool than speaker. It sounded beautiful on Classical and Jazz music and I also felt it was comparable to the 435al in a friends 1400 array. It was two different rooms and different types of amplification, but they were more similar than different to me. I like the sound of the 4" JBL. It basically beat out everything else I have owned since Widget recommend the 2440 4 years back. Results between the original Sl's vs Be's were not huge, but noticeable. Right now I have a crude EQ and I think it is not too far off still from the original. I need to drag them outside and take some measurements, but that won't happen for a couple of months due to summer family life.

Thanks,
Scott

[pos]

Thanks for the integration notes, I like having the idea of having the extra woofers in a separate box for easier room placement.

Having them side by side, or one directly above the horn will already help with width or height modes. You cannot have them too far away with a 1st order filter, as they will participate up to the lower midrange.

I need to drag them outside and take some measurements, but that won't happen for a couple of months due to summer family life.

No need to go outside: just take a close up measurement (say 10cm away from the throat) with the D2 in place, and then with the 4" Be (mic at the exact same position), and adjust accordingly.
These measurements will not be representative of the absolute response curve, but will be perfect for relative compensation.

[agronk]

I ordered before a New Year at local JBL dealer
Seems they had to sail from USA to my door!

[Mr. Widget]

Congratulations!
Have fun and keep us in the loop so we can share in the fun.


Widget

[srm51555]

Nice pickup. What will you be using for a DSP solution?

[srm51555]

Having them side by side, or one directly above the horn will already help with width or height modes. You cannot have them too far away with a 1st order filter, as they will participate up to the lower midrange.

I've been giving the extra helper woofers idea more thought and although I'd like the sensitivity, my room is too small for an extra set of 5cf of cabinets. Can a smaller cabinet yield similar results, or if you have any other ideas.

Thanks,
Scott

[agronk]

Nice pickup. What will you be using for a DSP solution?

I already bought Bss Blu-50& Blu-Usb
I`m chasing for pwr amp
Did someone tried Crown Xti-2000 with M2?

[srm51555]

I already bought Bss Blu-50& Blu-Usb
I`m chasing for pwr amp
Did someone tried Crown Xti-2000 with M2?

Not that I know of. Some members have gotten good results using the CTS series of amps by Crown though.

[1audiohack]

I don't know how much this matters but on a recent phone call with Crown Audio tech I asked about and was told that the I-Tech HD amps have considerably more DSP power than any of their other amps and that it is also about twice as fast as the previous generation DSP engine.

I also don't know how much of the available process power of the HD amps is used for the M2 program. I should have asked.

Barry.