microTower bipolar ML-TL for CHR-70 or EL70

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#63
A snapshot of the collage from the above document

microTower.jpg


dave
 
#66
doorman said:
Wow! Nice work Dave (& Chris) What are you powering them with?
Any comments on presentation vis a vis the Frugels? (level 1 build)
Don
Click to expand...

Don - thanks for the kind words - the Cinnamon Cherry Castle with CSS paper cone EL70 marked a big improvement over a pair of Buschhorn MkI /FE108E Sigmas in my wife's living room. They are being powered by some too bland for words Sony stereo receiver (25-30wpc is my best guess).


They sounded gorgeous on Bottlehead 2A3 Paramours, and surprisingly didn't run out of headroom at my modest listening levels in a 340 sq ft room, but a lot of folks would probably like to have about 10dB more power than that.

As for presentation vis a vis the Frugels with FE126E, you'd probably realize a bit more sensitivity than either EL70 or CHR70. The castle (one driving firing upwards) has less room placement issues than the true bipole variant, or any of the small rear mouthed BLHs that I've heard (Frugel, Buschhorn I & II,and Hornshoppe). Soundstage is wide, tall and ambient, but in my rooms at least, sacrifices the imaging specificity and depth that the horns, or most particularly the Fonken127 (probably still my favorite) can deliver.
 
#67
Dave and Chrisb, many thanks for the designs. I'm really liking the idea of the castle driver and I think it'd be a great topper for a FAST. I had been struggling with how to deal with the baffle step on the full-range driver(s) without losing output/sensitivity. This should do the trick.
 
#69
Inspired by DaveD (Planet10) microTower variants I was going to build a pair the 'Castle' variant until I was offered the plans for a prototype Mass Loaded Quarter Wave Air Coupler for twin Mark Audio CHR70.

The driver configuration is inspired by Castle Harlech and Howard S3 design, from the 90’s.

I have only had around 4-hours listen through my 300b monoblocs and they are rather impressive. I like this configutation.

Bass I suspect may be a little lower than the stock MicroTower with the added volume and the port is tuned down to 40Hz.

For those wanting to check out the build thread: http://www.audio-talk.co.uk/phpBB2/viewtopic.php?t=1742

The latest change I have made to the speakers is to install some spikes. This has tightened up the whole sound. Next up is to make some bespoke bases.
 

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#70
Toppsy said:
Inspired by DaveD (Planet10) microTower variants I was going to build a pair the 'Castle' variant until I was offered the plans for a prototype Mass Loaded Quarter Wave Air Coupler for twin Mark Audio CHR70.

The driver configuration is inspired by Castle Harlech and Howard S3 design, from the 90’s.

I have only had around 4-hours listen through my 300b monoblocs and they are rather impressive. I like this configutation.

Bass I suspect may be a little lower than the stock MicroTower with the added volume and the port is tuned down to 40Hz.

For those wanting to check out the build thread: http://www.audio-talk.co.uk/phpBB2/viewtopic.php?t=1742

The latest change I have made to the speakers is to install some spikes. This has tightened up the whole sound. Next up is to make some bespoke bases.
Click to expand...
Very nice work, Toppsy!
They look to have loads of that all important WAF!
Don
 
#73
Did you discuss moving the top driver to closer proximity to the front driver for less "bipole" dip?
Click to expand...

To be honest Dave, No. I built them to the design sketch I was given, other than changing the port to downward firing rather than the front firing port drawn.

Me thinks perhaps a MkII version may be on the cards. I'll check with the designer for his comments. At the moment he wishes to remain anonymous. But I'm sure you can guess who it is.

I must say that as built they sound very, very good. What I like is no loss of the large soundstage or ambience when you stand to listen.

This is the smallest sized driver I have built into cabinets and I was always sceptical on the performance claims of these smaller drivers. For big WAF these have changed my perspective.

I will add though that for personnal taste I much prefer your Fonken167's. But that's probably because of the larger driver?

Now what I would like is a Fonken design for the new Alpair12. That would suit me down to the ground.
 
#74
Humin.Bin,

Yes indeed it is the original build prototype MJK designed BLH for the Alpair10.

Not really fair to compare the sounds as they are not like for like.

The BLH has deeper bass, a bit too much in it's original design cabs and I had to add some serious damping to tame it. They are prone to room position and originally designed for corner placement. As you can see from the photo my room layout doesn't lend itself to corner loaded horns. But having siad that they give greater weight to the sound than the CHR70 MLTLs. My mate who until recent did not like single driver speakers simply loves the BLH's. So that says something of there performance.
 
#76
Toppsy said:
Yes indeed it is the original build prototype MJK designed BLH for the Alpair10.
Click to expand...

Actually we built the original. From that feedback and a suggestion by Scottmoose, Colin's build was revved and a further version was down with terminus at the front instead of the back.

Hopefully all the feedback will help Martin tune the design and he'll release it.

dave
 
#77
Actually we built the original.
Click to expand...

Arh! Yes I'd forgot that your build was ahead of mine. Sorry about that Dave.

As regards the the front terminus version this of the two is my preference as it is not so room position sensative and there is less bass gain. I have suggested to Martin that a smaller cabinet would help in the over bass issue. But apart from that it is a fine performer with the mods I did and passed on to Martin. I'm sure a MkII or would that be MkIII version will be penned sometime.
 
#78
I don't know how these are designed, but I do have on hand a nice cabinet of about 30L and with internal diminutions of 7"x10"x29". Can I make it into a nice CSS EL70 duel front back speaker? Unibox shows about f3 of 39hz with a 3" vent 6.5" long. Don't know what I would miss from MK mathcad sheets.

Bob Howell
 
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#79
Bob,
I'm not really qualified to answer your question I'm not really a designer I just build um. But for interest the ones I built are 36L cabinets (I make yours 33L). Without doing the maths on the Planet10 MicroTower I would suspect yours are about in the middle of the three. So I would have thought yes should work. I think your port length may be a little too long. Mine with a 3" dia x 3" long port the design specs are:

Anechoic
Fp = 45Hz
F3 = 40Hz
F10 = 35Hz

I'm sure DaveD at Planet10 or other able fellows on this forum will be more qualified to answer you.
 
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