Two MTM designs by Helmuth

[Helmuth]

Your results are certainly different than I have seen between particle board and MDF in the past. But, I can see based on your results why you would choose particle board.

I think the influence of wood choice is overrated. As you can see what has really effect is reinforcement. And the last resonances damp with bitumen pads.

Chip wood or MDF , Birch does not really matter to me, good total design right choices in XO with the used drivers is important.

Nothing more to it.

 

[Helmuth]

Interior reinforcement of the bassreflex design with wood

Damping with bitumen.

Tap it to hear it helps your ears are great tools. A extra reinforcement cross is placed.

Damping standing waves

Peak inside.

 

[jimfet]

Those Hivi ribbons in the Fat Boy was a nice selection. I have a set in my MTM speakers. They sound very nice.

 

[AltecDarpa]

good looking work! thanks for posting those.

 

[Helmuth]

Those Hivi ribbons in the Fat Boy was a nice selection. I have a set in my MTM speakers. They sound very nice.

They sound very neutral indeed. I removed them from the MTM because the TI100 from visaton has breakup at 7-8kHz and I wanted to crossover lower.

I now use the DT300 from Monacor a fantastic good 28mm dome for budget price.
I have several good tweeters around I have to say I was surprised by how similar they all sound, so my conclusion not much difference between top of the line tweeters. So one can better concentrate on the 4kHz and lower when you have a normal good dome.
I had a super tweeter of visaton that added something special very light aludome and voice coil horn loaded.

With the HiVi I want to make a OpenBaffle end this year.

Photo of the Monacor DT300

Only BIG sound BIG.

Measurement of my Swans RT1 the bottom grafic, and green line

 

[Helmuth]

Used drivers bandpass.
Monacor DT300 28mm softdome.

http://www.monacor.de/typo3/index.php?id=84&L=0&artid=3260&spr=DE&typ=full

Midrange Visaton TI100 titanium membrane.
http://www.visaton.de/de/chassis_zubehoer/tiefmittelton/ti100_8.html

Low a special type of the PL26. The vent is so big it fit my thumb. Magnesium frame. 10 inch 350Wrms papercone.

 

[Dan ʕ•ᴥ•ʔ]

Seriously nice work Helmuth! :yes:

 

[Helmuth]

I wish I had 1/10 of Helmuth's talent with cabinets! Serious - beautiful speakers.

What I do isn't difficult I only try to be smart when building a Box. I first think what I can make and not only what I like. And what is the cheapest.

Then you have to look for a good woodwork DIY shop with professional saw. When it is accurate sawn and you do it the way i did, then it is ready in a midday and perfect result.


So do not hesitate.

 

[wajobu]

Very nice work and informative thread!

 

[dnewma04]

Do you have full frequency response graphs for each of these speakers?

 

[Helmuth]

Do you have full frequency response graphs for each of these speakers?

yes on 0, 15 , 30, 45 degrees.

Bandpass on 1mtr. I flattened the rise at 8 kHz now these are old measurements.

bassreflex on 2 mtr

 

[Helmuth]

Bandpass measured on listening position.

 

[Helmuth]

Drivers used in the bassreflex.

Double coil carbon cone sub 200Wrms

Huge magnet a few cm bigger than a cd and nice sturdy aluminium frame.

http://www.monacor.de/typo3/index.php?id=75&L=0&act=8&act_sub=25&artid=2071&spr=DE&typ=u

Midrange Mivoc wtp138 and xgh258 ALU

http://www.mivoc.com/mivoc/details-einzel.html?marke=mivoc&artikel=WPT%20138

http://www.mivoc.com/mivoc/details-einzel.html?marke=mivoc&artikel=XGH%20258%20ALU

 

[Helmuth]

Grey doesn't fit

The tweeter is real good and low cost. A test of hobbyhifi measures high end. Very low THD <0.15%

 

[Helmuth]

Finishing the BR cabinets.

The PU glue foams up making a nice airtight finish.

 

[Rome]

Truly a wonderful display of craftsmanship & design integrity.

Rome

 

[Helmuth]

Thanks Rome.

bottomplate

 

[Helmuth]

To optimise air flow the baffle made round with a router. I also glue the nuts with PU because they can fall out whet pushing the bolt in.

To make a perfect fit on the front the frame thickness is cut out with a router.

 

[Helmuth]

Nice sturdy terminals of the BR.(monacor)

silver wire internal wire.

The bandpas is biwired. With special biwire cable a silver copper mix and robust fork clamps.

 

[Helmuth]

The front will covered by a extra baffle.

Fits perfect