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-   -   Dynamics, brute force and resolution with tiny feet. (http://www.diyaudio.com/forums/multi-way/220601-dynamics-brute-force-resolution-tiny-feet.html)

ingvar ahlberg 28th September 2012 05:51 PM

Dynamics, brute force and resolution with tiny feet.
 
For those here that donīt know me: i donīt like small speakers.

I donīt care about WAF, maybe because my wife never has objected to stuff like these in the livingroom:

http://www.seaside.se/~manoviia/moc11.jpg

I design and build mostly large speakers and i normally regard a driver with a sensitivity below 95dB as defective.

A couple of months ago fate or chance or whatever intervened and there was a sound reason for me to try to design something using Morel drivers.

Very reluctantly from start, i after a while, reading specs over and over, decided to do the best i could, starting at the budget end of those rater expensive drivers.

After a few days with the slideruler, paper and pen, WinIsd etc, i ended up with this.

https://lh5.googleusercontent.com/-F...070_resize.JPG


Having lived with those for some weeks now iīm still stunned by what they do, donīt understand how they can, but will recomend any one who wants something really small but likes the sound of really big speakers, try this design.

Drawings up here soon.

Ingvar

ingvar ahlberg 28th September 2012 08:39 PM

So, what is this then?

The two sligtly larger round parts are Morel CAW638, the smaller one in between is Morel CAT408.

These reside in something i would call a rather large aperiodic box.

During design i eventually ended in this box that had a teoretical f3 at 34Hz, decent for two 6 1/2", in reality, after breaking in, f3 is far lower.

First measurment, in my livingroom, no mike damping, just quick and dirty, no smoothing at all, still looks pretty decent.

http://i872.photobucket.com/albums/a...yonaxisraw.png


Ingvar

ingvar ahlberg 28th September 2012 08:58 PM

This is measuremnt from speaker in above picture, after about 1 hour listening, itīs pretty obvious that the f3 calculation was decently ok, which proves the old proverb, "even a blind hen".

With industry standard smoothing:

http://i872.photobucket.com/albums/a...axissmooth.png

Linear behaviour might be good, dont know if it is important, but dynamic capabilities is, i beleive, the most important part in a speakers way of reproducing recorded music in a lifelike and enjoyable way.

IG81 28th September 2012 09:10 PM

It looks like you have a kind of MLTL, with that vent at the bottom. Do you call it aperiodic because you heavily damped the line?

IG

ingvar ahlberg 28th September 2012 09:28 PM

No, its not any kind of qw related pipe or tl, itīs a quite large box, for 2x6,5" drivers, around 55 litres if i remember correctly, but vented, tuned to slightly above 30hz.

All inner surfaces are lined with heavy felt, except the entrance area of the rather long vent which is where the flow resistance material is placed, which is done at place of use, tuning them to the listening room.

Dufus 28th September 2012 09:47 PM

Interesting. How do they sound? By big do you mean they reach low or they have really big soundstage?

tuxedocivic 28th September 2012 10:09 PM

Is your cross over at 2khz? Looks like you have a polarity issue. There's a 10db droop right there.

sreten 28th September 2012 10:30 PM

Hi,

No doubt though you can probably do better with better value drivers
in similar cabinets. Morel drivers although expensive, have never stood
up as value for their cost, in all the comparative DIY testing I've seen.
(Or do similar for quite a bit less.)

rgds, sreten.

Aperiodic loading is very different to tuned vented (damped or not) loading.

ingvar ahlberg 28th September 2012 10:50 PM

X-over at measurment time was suposed to be around 3k, after rework and fiddling with components that works, still a litte dip, 4dB or so, around 2,5k.

How they sound?
Now we are entering the subjecteve realm, ok with me, music is as far from objective anything can be. Bear in mind, i designed these speakers, i dont write about them here with a comercial interest, all drawings will be published here and availlable in pdf file for anyone who wants them.

I think:
LF extension is really astonishing with impact or force like very much larger drivers more associated with pro or studio use, still very tonaly corect, You allways hear the note the baseman plays, not just a rumble.

Voices are lifelike and present, maybe lacking in the sense of actual presence and force as a really good 12".

Soundstage is ridicously good, and separation/resolution of unison voices is the best iīve ever heard.

Drawbacks?

None.

Hullo! There we caught the liar!

Major drawback is very poor sensitivity, measured after a few hours of use, gives 2,83v @ 100Hz 1M = 92dB , as it is a 4ohm load it also needs an amp with decent power and current capacity.

My tiny ML11 amp gladly produces 120dB with these speakers and a simple EL84PP (Edison12) has no trouble playing music at fairly realistic levels through these speakers

ingvar ahlberg 28th September 2012 11:10 PM

Quote:

No doubt though you can probably do better with better value drivers
in similar cabinets.
Suppose Youīve allready tested.

[QUOTE][ Morel drivers although expensive, have never stood
up as value for their cost, in all the comparative DIY testing I've seen./QUOTE]

Hearsay or experience?

Quote:

Aperiodic loading is very different to tuned vented (damped or not) loading.
And?


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