A garage style M2 build?

[grey]

I've acquired the basics of what it would take to do very loose assembly for an M2 monitor. A custom enclosure is possible, but I don't do wood. I can do metal, but no wood yet.

What is all of the official hardware to mount the driver to the horn and the horn to the cabinet? I do have the adapter rings. This is my big question so far.

I will initially be using the 4507 cabinets. All input good or bad is welcome on this idea. This is what I have and would prefer an open mind. A crossver at 80Hz to subs is defintely there.

 

[grey]

 

[SaturationPt]

Why would you cross a 20Hz speaker over at 80Hz to a subwoofer?

 

[grey]

Why would you cross a 20Hz speaker over at 80Hz to a subwoofer?

The plan is to mount the 2216 in the 4507 cabinet that is tuned to 40Hz.

 

[grey]

Even if I could play around below 40Hz, I would rather have a channel dedicated to doing great vocals, etc. between 80-800Hz. I've been doing fully active for many years and it's a good question. A tremendous amount of power is required in the lower frequencies. Does this make sense so far?

I have an array of subwoofers that will do just fine up to 80Hz and they really need tweaking to do their best. I don't have the expertise to fine tune this array, but that's going to be part of the fun.

 

[SaturationPt]

More complexity = more fun!

 

[jmpsmash]

Unless you have some specific room nodes between 50-80Hz, 80Hz is still directional despite being below Schroeder. I have tried it in my room. YMMV.

 

[Riley Casey]

Unless you have some specific room nodes between 50-80Hz, 80Hz is still directional despite being below Schroeder. I have tried it in my room. YMMV.

14ft wavelength says what? Of course I wouldn't completely discount being able to be control directivity at 80hz as I do it routinely in large venues with a truck load of large PA subwoofers but not sure that's likely to be an issue in home audio.

 

[grey]

Unless you have some specific room nodes between 50-80Hz, 80Hz is still directional despite being below Schroeder. I have tried it in my room. YMMV.

I had the B460 and BX63A. The crossover is 63Hz. I remember reading about how they arrived at that frequency and I can't recall the details. This was before the later popularity of 80Hz.

There is a dsp calibration for the M2 to integrate with the SUB18 at 55Hz, 24dB. Not sure how anyone arrived at this frequency either. That should be high enough to keep me out of trouble. Maybe I will drop that in work from there.

 

[grey]

Working through some of the hardware. There seems to be some good mojo so far. Most of it just needed attention or a few inexpensive parts. It all passes music.

 

[grey]

All of the expensive little bits are here from Redco and Mouser. These things add up and I already had half of it on the shelf. This is my first experience with Redco for all of the custom cabling parts and they are top notch. I will be soldering up my own sauce, but they have a service to build anything you want with high quality parts.

It may be early on to think about building some cabinets that are correct. If it turns out that I like these, I would be interested in finding a cabinet maker. Preferably in the major Texas cities on in to Louisiana. I had a plan to contract a good friend and artisan woodworker to sort this out. He didn't have a large CNC table and was working with him to get that capability into his shop. Unfortunately he is no longer able to walk the earth with us. Not looking to violate AK policies, so shoot me a PM and we will go barter town if necessary.

Btw, is a "pulse-rated" capacitor preferred in a passive crossover component? Mouser didn't have a pulse-rated version in stock and digi-key does.

 

[tarior]

Why would you cross a 20Hz speaker over at 80Hz to a subwoofer?

I would say to get away from the low frequency excursion of the speaker modulating the mid-bass.

 

[SaturationPt]

I would say to get away from the low frequency excursion of the speaker modulating the mid-bass.

I used to think that way also, until I realized that every significantly different frequency “modulates” another range of music, ... and in a mic’ed recording that’s also true on the recording side. There is no escaping it.

 

[tarior]

I used to think that way also, until I realized that every significantly different frequency “modulates” another range of music, ... and in a mic’ed recording that’s also true on the recording side. There is no escaping it.

That's certainly true. However, it's only the woofer producing low bass that's moving back and forth a half inch or more. Is it a big deal? Maybe? Maybe not.

 

[SaturationPt]

That's certainly true. However, it's only the woofer producing low bass that's moving back and forth a half inch or more. Is it a big deal? Maybe? Maybe not.

I’ve struggled with that question for years. Does the more specific frequency requirement of a 3-way plus subwoofer reduce doppler distortion, is a full-range better because it doesn’t suffer from crossover phase-shifts and other artifacts of multi-source sound, somewhere in-between, ... is a recording that’s made on a microphone, the diaphragm of which does exactly the opposite of the full-range speaker driver cause full cancellation of this doppler-distortion / IM-distortion? Speakers are imperfect, as are microphones, as is air, so I don’t believe that there is a single completely correct solution.

Personally I love the M2, and that much music (and movie audio) was mastered using them as a reference certainly adds credibility to the 2-way design.

 

[tarior]

I would love to check out a pair of M2. If they are as good as they are reputed, I'd be sorely tempted to dump a ton of vintage to finance a pair.
As an aside, every time I've ever run a sub, with the mains on a high pass, I have always noted that the midbass seemed cleaner and more defined. Was it from cutting back on that doppler effect, or was it just from gaining some headroom?

 

[grey]

I'm very close to qualifying the audio chain before the amplifiers. It will look something like this:

Lyrion server>LAN/WLAN>Squeezelite>BSS blu-usb>BSS-160>4x digital out cards>Lynx Aurora 16



Almost all of this hardware was dumpster rescues with no power up. Had some some fun over the winter with repairing them and learning how they work. Still have several questions on proper clocking, sample rate conversion, optional cards, etc.

 

[grey]

This winter has seen some delays on the project. I was not confident with my old external sound card for measurements. A Motu M2 sound card is a another recent dumpster pick. There is also a couple of LinearX measurement mics. I want to do my best on a budget to have repeatable and useful measurements.

A small update on custom cabinets. I've found someone with a cnc router that is willing to take in small projects like this. When I did car audio some time ago, I had brilliant cabinet designer on speed dial that could read woofer parameters and precision cut MDF.

The 4507 cabinets have a cross brace that interferes with the 2216 frame. This can be easily clearanced with an oscillating blade. These are nice looking AE finished cabs, so I've been apprehensive with knifing them up.

Most of the suggested plastic tapping seems to be an M6 thread. I will probably just focus on building a tap guide and getting this part done for now.