DIY MTM driver replacement recommendations

[Richard Ellis]

Hi all:
I have a DIY tower that finally gave up the ghost..the drivers finally rotted out.
I'm looking to rerdrive the system..she has two 6 1/2 "" woofers with a rather generic Piezo for the top end, its' nine inches wide by thirteen inches deep some fourty inches high, VERY well made of one inch thick MDF screwed every five inches with woodglue.
Volume was set at three cubic feet...the system 'was' at .933 Qts.
I would like to keep her a sealed system...porting is not really my thing...but I am open to suggestions...Of course I will need to put an extended baffle "plate' for the slight dimensional differences of the new drivers............Ideas?
______________________________________Rick............

 

[weinstro]

Go to the FRD consortium and download the basic spreadsheet modeling program.

Next, go to Madisound, PartsExpress, and ZaphAudio and download information on available parts. Model and see what might work.

You need to figure out if the design is a 2-way or a 2.5 way.

Also, if you change the drivers, the crossover must be scrapped and redesigned. Madisound can design you one for a few, which might not be optimal, but should be OK.

 

[sreten]

Hi,

3 cuft is the external volume, internally it is ~ 1.8 cuft.
Do some seaching on the loads of 6.5"/ 1" MTM designs available.
Sealed is unlikely with ~ 0.9cuft per 6.5" driver.

/sreten.

 

[dublin78]

The vented floorstander version of this is 2 cubic feet. Near enough? 2x 6.5" MTM. Cheap too.

http://www.zaphaudio.com/BAMTM.html

 

[sdclc126]

The vented floorstander version of this is 2 cubic feet. Near enough? 2x 6.5" MTM. Cheap too.

http://www.zaphaudio.com/BAMTM.html

Cheap AND excellent!

 

[Richard Ellis]

Thanks for the info ya all......I went to measure the dimensions again, and yes I did the rookie error & didn't take into account wall thickness (This was some fifteen years ago!) as the outside dimensions came up 2.9218 cu feet, inside however is 1.7867 cu feet........now take into consideration the "stuffing" and we get about Two cu feet.
I think I will go with the sealed metal woofer setup...cheap & accurate....I'll go sealed as I have a subwoofer to bring up the bottom end & I'll roll off the towers rather low (70 Hz) & redirect the signal to the sub.
I have a Carver TFM-15CB (100W rms per) to run it all.
Thanks again guys/gals?
_________________________________Rick...............

 

[dublin78]

Which drivers and XO will you be using?

 

[Richard Ellis]

I think I will use the specific drivers & x-over as noted in the Zaph link...kinda odd f response with these 'metal' woofers...10K upper end??? Must be character of the beast.
I'll run them full range to start as I have to redo the sub as I disassembled them before moving down here....besides I'll have to really think thru how I'm going to roll-off the towers...I could cheat & simply slap a bi-polar cap at say 60-100 uF...but that isn't right....I'll have to read up on crossovers more before that.
_____________________________________Rick............

 

[sreten]

Hi,

For music I would say no subwoofer required if you vent the boxes.
For AV you could just use the Subwoofer with the LFE channel.

...I could cheat & simply slap a bi-polar cap at say 60-100 uF...but that isn't right...

Too right its not right and it will not work.

/sreten.

 

[SyncTronX]

The vented floorstander version of this is 2 cubic feet. Near enough? 2x 6.5" MTM. Cheap too.

http://www.zaphaudio.com/BAMTM.html

So where do you get the box for it? Or did I miss something
along the way?

Where to get the box, which one, and how much.

thank Guys,

SyncT

 

[Helmuth]

If I got it right you do have 81 liter (3 cubic feet)

For a sealed enclosure I would recommend visaton w170S. 8 ohm 2 parallel. QTC=0,83 near ideal Q. price about 28 euro.
visaton

An externally hosted image should be here but it was not working when we last tested it.

klick here simulation

Do not use any filter with the w170s. and connect a 4uF capacitor in series with the DT300.

Tweeter monacor DT300 8Ohm has a spl of 93 db that's enough in combination with the w170s about 25 euro

An externally hosted image should be here but it was not working when we last tested it.

dt300

A Dutch shop witch ships world wide.
http://www.bmm-electronics.com/

 

[Helmuth]

I also used the W170s once for a TL project. Realy sounded very low THD to me.

 

[Helmuth]

Simulation for 2 cubicfeet. 65 liter with w170s it is not very critical you will see.