John Krutke's MTM (Vifa XG18 / Seas 27TDFC)

[scone]

I'm looking at perhaps building these this winter. I can't find any information on them other than the stuff that John posted on his own site . Has anyone built or heard these?

How do they sound in the low-end? I saw the response curves on John's site, but they don't mean all that much to my relatively untrained ear.

Also, I'd like to build my own cabinets instead of using the pre-built one's the speaker is designed around. I'd also like to build a wooden outer shell that will house the MDF box inside of it. Something like what andrikos did to his line-array (3/4'' birch glued to 3/4'' MDF with a 2mm layer of dynamat in between). This is entirely for aesthetic reasons (great speakers btw Andrikos, they look amazing). However, I'm wondering if it will change the way the speaker sounds since the drivers would be mounted in a birch baffle of sorts, and driver would 'see' a thicker overall shell. Is this a feasible idea, or should I stick to building them the way they were designed and veneering the outside?

-tony

[Zaph]

These were presented at DIY Chicago yesterday. See Paul Hilgeman's writeup here:

http://www.madisound.com/cgi-bin/dis...gi?read=324578

Pictures are here:

http://webpages.charter.net/tjt123/C...004/index.html

What a great bunch of guys and some seriously good speakers. There wasn't a bad sounding speaker in the house.

John

ps. A thicker baffle is fine, just be sure to allow sufficient breathing room behind the speaker. You may have to seriously angle and enlarge the inside diameter.

[scone]

Thanks John

ps. A thicker baffle is fine, just be sure to allow sufficient breathing room behind the speaker. You may have to seriously angle and enlarge the inside diameter.

Is it also alright if the baffle is a little bit wider and a little bit taller than in your original design? If I add a 3/4 in. wooden shell around the outside of the cabinet, the baffle will be approx. 1.5 inches wider and 1.5 inches taller than before. I don't pretend to know anything about how the size and shape of a baffle changes the sound of a speaker so I'm not sure if it's ok to do this.

Out of curiosity, where in the cabinet did you mount the crossover?

[cjd]

First off, I can say that these truly sound awesome.

Bass response is excellent, and I'm not sure it's reasonable to expect more out of what is in this design.

On a tangent, maybe John will discover that orchestra stuff really has more depth once he gets his new sub running. I really should have had Paul play the last movement of the Mahler, not the first. Whooo! 16hz pedal tones on the organ really *do* change the sound.

Changing the dimensions of the baffle can impact sound. How much and whether you'll hear it is a bit up in the air perhaps - depends on the extent to which you change the dimensions. However, you could build the box a bit deeper to keep the correct volume and keep the baffle dimension as designed.

C

[scone]

Changing the dimensions of the baffle can impact sound. How much and whether you'll hear it is a bit up in the air perhaps - depends on the extent to which you change the dimensions.

So upon reconsideration (and a few more hours of searching the forums ) I realize there is no reason to make the outer 'shell' out of solid wood. I think i'll use something like 1/4'' finnish or birch plywood. That way the baffle dimensions remain close to the original (now growing by 1/4'' extra on all sides, so 1/2'' total wider and taller). I'm assuming the such a minor change shouldn't impact the sound quality in any audible way?

I like the idea of using real wood on the outside (vs. veneer) because that way i can round the corners slightly and sand and stain them. I don't think i'd do too well with veneer as I've never tried, plus nice veneer is pretty expensive and at that rate i might as well use real wood.

[Cruiser]

Scone.....where did you find the Seas tweeters....i'm looking at these as well, but it doesn't look like PE carries them?

[bhg41088]

www.madisound.com

[sbolin]

Originally posted by Zaph
These were presented at DIY Chicago yesterday. See Paul Hilgeman's writeup here:

http://www.madisound.com/cgi-bin/dis...gi?read=324578

Pictures are here:

http://webpages.charter.net/tjt123/C...004/index.html

What a great bunch of guys and some seriously good speakers. There wasn't a bad sounding speaker in the house.

John

ps. A thicker baffle is fine, just be sure to allow sufficient breathing room behind the speaker. You may have to seriously angle and enlarge the inside diameter.

John-
In another post (your summary) you had some good things to say about the Vifa XT. How do you rate the Vifa XT/XG and the Seas L18s? All these interest me, along with the Peerless HDS (can't think of the number off the top of my head, and too lazy to look it up).

Paul H. had good things to say about your speakers, and the L18s really look pretty good, nice work.

[Zaph]

Originally posted by scone
Out of curiosity, where in the cabinet did you mount the crossover?

I mounted on the bottom, near the back. The crossover was simple enough that I could fit it all on one board.

Originally posted by cjd
Whooo! 16hz pedal tones on the organ really *do* change the sound.

Heheh, your house rattling apart changes the sound too.

Originally posted by sbolin
In another post (your summary) you had some good things to say about the Vifa XT. How do you rate the Vifa XT/XG and the Seas L18s? All these interest me, along with the Peerless HDS (can't think of the number off the top of my head, and too lazy to look it up).

Hmmm. Of all those, I think I'd personally pick the Seas L18's. (H1224) Last Saturday was the first time I heard the XT and it did sound good, but given the price, I sure can't say it sounded 110% better than the XG. These are all great drivers however. I think which one you like might depend on your cone material preferences and/or your music preferences.

On my web site, I wrote this article about cone material which might help people decide which speaker to pick.

John

[lowHz]

I also heard these speakers at DIY Chicago. I think that they sounded fantastic. As John noted at the event, they have a relatively low crossover point and avoid the lobing problems that MTM's typically exhibit. I thought they had a nice sense of space and ambience. All of John's crossovers sounded first rate.

I'll have that subwoofer out to you soon enough John. I can't wait for you to give it a run for its money.

Chad