DIY mtm tower SEAS beryllium tweeter and 7 inch Nextel drivers.

  • Thread starter Thegenuinearticle
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Thegenuinearticle

Audiophyte
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16
#1
I built these towers with in mind to see what was possible with a given budget to try and meet or exceed the performance of other turn key speakers that cost 3-5 times as much as my total expense in components and materials. The result is a very unique sound signature that is revealing and engaging. Hope you enjoy the build pictures! BTW the table is solid walnut which I made as well and additionally I built the subwoofer cabinet also. I have many more build pictures including a very capable and large 3 way center channel. Thanks for viewing...
 

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KEW

KEW

Audioholic Warlord
Ratings
5,014 22 9
#3
I built these towers with in mind to see what was possible with a given budget to try and meet or exceed the performance of other turn key speakers that cost 3-5 times as much as my total expense in components and materials. The result is a very unique sound signature that is revealing and engaging. Hope you enjoy the build pictures! BTW the table is solid walnut which I made as well and additionally I built the subwoofer cabinet also. I have many more build pictures including a very capable and large 3 way center channel. Thanks for viewing...
Looking good!
But I want more specifics!:)
So what was your "given budget"?
Will you get a chance to A-B against the turn key speakers costing 3-5 times more?
Did you have a specific speaker or two you were targeting to meet/beat?
Which ones?
 
Swerd

Swerd

Audioholic Spartan
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4,890 11 6
#4
Thanks for all the nice pictures. Yes, we want more specifics :).
  • Your cabinets look like an MDF layer inside of plywood. Are they each ¾" thick? With all the cross bracing you included, why did you go for the double thickness?
  • Are your cabinets designed for standard ported bass alignment, or something else like mass-loaded transmission line? What is the tuning frequency?
  • What is your crossover frequency and design – schematic diagram, photos?
  • Please tell us more about why you chose those particular drivers.
 
speakerman39

speakerman39

Audioholic Overlord
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3,028 6 4
#5
Very nice work! I would give anything to be able to do something like this. Very much interested in the crossover topology. Who did the crossover design work? Very impressive congrats! :)


Cheers,


Phil
 
T

Thegenuinearticle

Audiophyte
Ratings
16
#6
Thanks for the welcoming reception and interest in the speaker. I hope some answers can be given for a few questions.

-I wanted to add some mass to the 0.75 inch plywood to keep any ringing or resonances down so I laminated the insides with .5 inch mdf.

-Crossover is a passive LR second order 12 db @ just under 2kh. Jantzen capacitors and wax coil inductors largely make it up.Passive units are mounted externally which in my opinion is the best route because they can easily be serviced or conversely the speaker can be switched to an active. No matter what the textbooks say about mtm's I can never get the desired result they suggest be used with them regarding 3rd order filters. Maybe with smaller drivers and closer center to center spacing of the drivers that can work,but with this setup 2nd order whether BW or LR was the clear winner.

- Port tuning is 38 hz at 3 inch diameter just a touch over 9 inches in length. With the foam lining I think the drivers are responding to a bit larger of an enclosure other than the 1.44 cubic feet. They actually extend down into high 20 hz territory with very respectable output. I run them fullrange and it allows me to cross my subwoofer fairly low at 40 hz 24db. With the right gain balance there is little if any localization of the subwoofer and with about 75-100 watts being driven to the towers the healthy motors of the woofers allow for some ability to withstand unloading beyond port tuning with no real signs of stress. I highly recommend the precision port products if one wants to DIY port a speaker. They have a massively tapered flange opening which I really do feel eliminate distortion and port chuffing.

-I chose the drivers based on previous experience with SEAS products but wanted a speaker that straddled the line of some warmth with the treated paper cones and also have some nice extension and detail in the upper octaves. Additionally this SEAS beryllium tweeter virtually had no reviews or feedback from other enthusiasts for the most part and honestly curiosity set in. Yes it's expensive but it is very nice to listen to.

-Here is a response graph of the speaker. Below 200 hz you see my nasty room modes . Its a lively room so even though it is a nice measurement I also roll off some 4,8,12 kh by about 1.5 db to what my ears seems more natural and relaxed. Measurements are of course one thing and voicing, imaging, and timbre are only really things that listening reveals.

-All in all I spent around $3,000 on total materials. I would say I definitely ended up getting my money worth and would have been unlikely to yield the same performance/ value if I had spent 1-2 times as much on a turn key speaker. It certainly would not have been as rewarding and satisfying as the build process was so in a way inherent value is there that can be hard to gauge.
 

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2channel lover

Audioholic General
Ratings
599
#8
Looks great...the drivers, are top shelf.

Far too much work for my patience, and skill set, but I'm sure they are very rewarding.
 

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