[jimbones]

Hi,

Looking for a high quality midrange driver to be used for open baffle 140 hz to 1800hz. 88 db eff.  Cost not an issue right now. Can anyone suggest?
Note: I do not want to use DSP to boost!!

Thanks

[JohnH12]

Looks like you would have to use a wide baffle and operate above the first dipole null to make that range work. 

[jimbones]

John, yea Im thinking a baffle of about 25 inches maybe even 30 inch

[JohnR]

Cost no object, if you can raise the lower crossover frequency then something like 4 x Neo10 as used by Danny Richie in the Super 7 would be interesting.

Otherwise, perhaps a cone driver like the AE Dipole10 or TD12M.

[jimbones]

Cost no object, if you can raise the lower crossover frequency then something like 4 x Neo10 as used by Danny Richie in the Super 7 would be interesting.

Otherwise, perhaps a cone driver like the AE Dipole10 or TD12M.

John, I can not raise the lower cutoff frequency. Do you think there is an 6,7, or 8 inch driver that will work? I will consider the NEO 10. Is that 4 per side? or 2 per?

[jimbones]

Do you think a Scan-Speak 18M/4631T Revelator 7" Midrange would go to 150hz?  It has a fairly high Q of 0.6.

[AJinFLA]

John, yea Im thinking a baffle of about 25 inches maybe even 30 inch

That's IB, not OB 

[jimbones]

That's IB, not OB 

ha ha yep. theres a graph floating around that gives baffle dim vs low cutoff frequency. It says 22 inch for 150hz

[AJinFLA]

ha ha yep. theres a graph floating around that gives baffle dim vs low cutoff frequency. It says 22 inch for 150hz

Dunno about all that, but for less guesswork, you could try the program I linked here http://www.audiocircle.com/index.php?topic=149607.0
Which allows you to enter not just the baffle size, but the relevant T/S parameters of the specific driver, so you see the roll off.
It's straightforward enough (just an Excel spreadsheet) that even dummies like me can use it. 

[AJinFLA]

Btw, doesn't Danny GR make an OB specific midbass?

[jimbones]

Dunno about all that, but for less guesswork, you could try the program I linked here http://www.audiocircle.com/index.php?topic=149607.0
Which allows you to enter not just the baffle size, but the relevant T/S parameters of the specific driver, so you see the roll off.
It's straightforward enough (just an Excel spreadsheet) that even dummies like me can use it. 

I did use it and it comes fairly to what I measured in my current set up. It is -6db at 185 hz. The GR subs go up to about 140-150 hz. I have a small gap 150 to 180 hz. I have a sizeable dip in that area.

[JeffB]

There are lots of old threads on this forum using the Visaton B200 in open baffle.
I built an open baffle experiment a long time ago using an 18" flat baffle (no wings) with
a 15" woofer.  For the top I had two drivers that I experimented with.
The Visaton B200 and the TangBand w3-871.
I have a surround receiver allowing me to vary the low-pass filter to the 15".
The 15" sounded best with lower cross-over points, but the system as a whole worked best with a 200Hz cross-over point.
I had no other corrective circuitry, and the system does not quite work without some added filter, although it came very close.
The Visaton B200 has something magical going on in the midrange.  However, the higher frequencies were too bright for me.
Perhaps the right filter could have made this work.
It has been a long time since I listened, but my recollection is that it blended fine with the 15".
I spent most of my time listening with the TangBand w3-871.
The upper frequencies were better than the B200.  I believe the w3-871 was not quite playing low enough to integrate with the 15".
The sound was a tiny bit bright with a small whole in response before integration with the 15".
The non flat frequency response eventually made me put these away until I have a solution.  I am really lazy about this.
That being said this combination still sounds better than maybe any speaker I have ever heard, and I have been to the audio shows to hear all the expensive speakers.
The Visaton sounded better than the Tang Band in the lower midrange, but the Tang Band was better in the upper midrange.
One day maybe I will buy mini-dsp and try to get all 3 drivers working together and flatten the frequency response.
I just fear an inability to tune this by ear and an inability to measure the response accurately.
A good tweeter will play the really high frequencies better than a w3-871.  Everything is a compromise, but the incredible mids were worth giving up the highs.
I am really intrigued by the Tang Band w5-2143.  I have never heard it, but it seems like a nice compromise between the above two drivers.  Its Qts is perhaps too low though.

[JeffB]

Looking again at your requirements again.
140 hz to 1800hz. 88 db eff

I think the Visaton B200 will need a corrective circuit to tame frequencies between 900-1800hz.
Since your baffle is going to be wider, I think you might be able to make something like the Tang Band w3-871 work.  Sadly it is not made anymore.
The frequency response on the w5-2143 looks great, better than the w4.  Don't know if it lies.
https://www.parts-express.com/pedocs/specs/264-958--w5-2143-spec-sheet.pdf
https://www.parts-express.com/pedocs/specs/264-957--w4-2142-spec-sheet.pdf

[Dmason]

Any of the older, Alnico, Isophons will offer up midrange magic in spades.  Great upper range, easy tweet implementation.

[jimbones]

Ok so let me share this: I am currently using a Satori MW16P. It has wonderful sound quality. I just find that it is strange that I can not get it to play down to 150hz (-6db). 

[JohnR]

You are trying to "get it to play down to 150hz" without using any EQ?

[jimbones]

You are trying to "get it to play down to 150hz" without using any EQ?

Correct. Although an option Im trying to see if I can do it without active DSP.

[Tyson]

If you want decent lower midrange/bass, you'll need a bigger mid/woofer.  Like 12 inches, and something that is built for OB, not a driver designed for a box speaker. 

Even with that, the driver will have a rising response - as frequency increases, so does the output.  So you'll have to shelve the top end response of the speaker in order to get a flat FR.  That's important to understand, because when you try to match it to a tweeter or to another midrange driver, you have to look at the sensitivity of the driver AFTER the shelving has been done. 

For example, the 12 inch driver might play a 800hz note at 97db with 1 watt, but play a 100hz note at 90db with one watt.  You have to shelve the top end response down to 90db so it matches the output at 100hz (ie, you now have a flat frequency response).  That's important, because if you have a tweeter that's 95db, it will need to be shelved down to 90db as well. 

OR, you could just buy one of the OB kits from a reputable dealer (like GR Research!) and all this stuff is already worked out for you, and you only need to assemble and finish it. 

But saying "I have a driver (Satori) that I really like already that I want to turn into an OB speaker" is generally not going to work out very well.  Just sayin'.

[jimbones]

Making sense now, thanks Tyson for the explanation. So although i prefer to not use my minidsp, i will bring it out to see just how much boost i need and if it works.then ill consider my options.

[Danny Richie]

Btw, doesn't Danny GR make an OB specific midbass?

Yes we do. The M165NQ and M165NQ/16's are designed for that application. You can see them here: http://gr-research.com/m165xwoofer-2-1.aspx