Looking for HiFi High SPL Project

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yet another pic

where its at now.
 

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Konnichiwa,

DrumDude said:
would the mids be unaffected by lack of an enclosure?

Due to the delayed reflection of the woofer cone, which should be damped by paking the area behind the midrange with sound absorbing/delaying fibers and maybe some foam/felt on the woofers dustcap) the midrange becomes in effect cardiode in dispersion pattern.

DrumDude said:
also would this design have good dispersion?

Depends on how you define "good dispersion".

The speaker will display considerable off-axis attenuation, but much more evenly with frequency than most speakers.

I recently listened to the original in the picture and it is an absolutely outstanding speaker. Drivers are made all in-house by MEG, they use a 5.25" Midrange and 1" Dome in the 90db/w/m sensitivity range, backed by around 100W each and double that on the woofer, woofer is also cardiode by virtue of a variation of the U-Frame with flow resistances and EQ.

Crossover to the Midrange is at 550Hz & 2.8KHz. Should be non too hard to replicate DIY, except maybe the wwoofer loading. I personally would bulk the Midrange up and try crossing over lower....

The Speakers sailed effortlessly through one of my extreme tests (St Saen's #3 finale, no compression) in a large studio equipment shop (larger than your space) with only the very low organ pedal notes a little light, not bad at all for an 18"Cube without passive resonator, reflex et al.... ;-)

I suspect a sealed sub for the 16 - 32Hz range would be good, maybe a dual 21"...24" mono one or an EV 30W or Fostex FW800....

Sayonara
 
Looking for largest Sweet Spot

In the dark grey area is where most critical listening will be done. Thats where I would like good imaging. The lighter grey area my main concern would be frequency response and fairly even volume. I realize I am trying to balance 2 opposing ideals. Just trying to learn and striving to create the largest "Sweet Spot"
An externally hosted image should be here but it was not working when we last tested it.
 
Re: last pic for now

DrumDude said:
Computer generated pic of possible speaker layout. the white panels on the wall hide IB subs. Yes thats a huge mirror on the wall, I know its sonicly bad but needed for dance studio. I plan on doing some room treatment afater its done. right now it echoes bad.

Idea! A big curtain to hang in front of the mirror... then later on you can put a projector in the room. This looks like a super project :)

Don't forget to check the max SPL of those bass drivers- I ran the numbers for two 15"s at 20hz, and it didn't reach your SPL goal with 14mm xmax. I recommended the four Dayton IB 15"s based on the volume displacement required for your bass goals.
 
Re: Looking for largest Sweet Spot

Konnichiwa,

DrumDude said:
In the dark grey area is where most critical listening will be done.

Given that this is at a rather large distance, you want a very controlled directivity (in other words good and narrow beaming) while for the light grey area the off axis response flatness needs to be good....

I would definitly suggest dipole with absorbed/diffused rearwave or horns for the upper bass way into the upper midrange, from there horn or ribbon on waveguide (or at least with felt strips on the sides to limit horizontal dispersion) or a dome tweeter with a waveguide (there are some ready build ones by Vifa (now Peerless V-Line) and Peerless, also Morel IIRC, alternatively mount a 1" dome into a modified commercial pro audio waveguide (see discussion elsewhere here).

I suspect that the option of an 18" Cube as modified U-Frame loaded with an "upper bass and lower midrange" pro audio woofer (I hear good things about the Eminence Omega Pro 15) for the upper bass and lower midrange, with an Audax PR170Z0 placed on a suitable baffle as semi-coax would bring good SPL from maybe 80Hz or so upwards for large spaces and "dancefloor" SPL's, at slightly saner levels you can probably EQ the U-Frame to around 50Hz and all the way to maube 4KHz or so.

Then fit a treble unit with suitable matched directivity, let the monster IB take care of the rest and you are done.

Sayonara
 
Re: Re: last pic for now

joe carrow said:


Idea! A big curtain to hang in front of the mirror... then later on you can put a projector in the room. This looks like a super project :)


I did think to pull a flex conduit in the ceiling with that in mind down the road.

Don't forget to check the max SPL of those bass drivers- I ran the numbers for two 15"s at 20hz, and it didn't reach your SPL goal with 14mm xmax. I recommended the four Dayton IB 15"s based on the volume displacement required for your bass goals.

I have 22" between truss uprights. I was planning on trying to shoehorn 2 15's per side something like this. I don't have a feel for how much of a compromise this will be in terms of SQ.

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