You got it.
Basically the same little Vifa driver, same crossover and a 15" GRS woofer instead of the 12" Peerless. Much larger baffle, tho. It's a 1/4 sheet of plywood with 6" wings.
John should have details and photos here soon. There may be some slight changes in the crossover. You should be able to build a pair for about $260, complete (in the USA).
Or under just $100 per side for drivers and all crossover parts. Wood, screws, glue are extra.
Has anyone evaluated the MCM Audio Select 21'' Die Cast Professional Woofer - 800W RMS | 55-2985 (552985) | MCM Audio Select
21" ?
the datasheet lends it to be a possible candidate. holy swept area batman
21" ?
the datasheet lends it to be a possible candidate. holy swept area batman
So disappointing!!!
Yes I did and the driver's measured T/S parameters via WT3 were so far off as to make the driver near useless!! QT over 2 and true efficiency of about 89 DBW. Huge QE like the magnent is made from defective materials or not properly charged. Physically the driver is beautiful, 125 oz magnet, 1/2" top plate, nice cast aluminum frame and all the rest. Really a shame. I passed along my measurements to MCM with some technical notes. They said they would look into the situation, but have heard nothing since.
As far as I can tell what I received is typical, at least of the initial production run. IF, MCM were to deliver a driver remotely close to the published specs, it could be a game changer. I did try to use it, need to post a picture. Will forward one to Pano and he will post.
Bottom line is you can spend less money for a couple of cheap 15's and do way better. You can use a plate amp and get it to work well, but after spending $160 you have to spend an additional $125 to get it to perform. Not a good deal. Plus the added complexity and weight.
Yes I did and the driver's measured T/S parameters via WT3 were so far off as to make the driver near useless!! QT over 2 and true efficiency of about 89 DBW. Huge QE like the magnent is made from defective materials or not properly charged. Physically the driver is beautiful, 125 oz magnet, 1/2" top plate, nice cast aluminum frame and all the rest. Really a shame. I passed along my measurements to MCM with some technical notes. They said they would look into the situation, but have heard nothing since.
As far as I can tell what I received is typical, at least of the initial production run. IF, MCM were to deliver a driver remotely close to the published specs, it could be a game changer. I did try to use it, need to post a picture. Will forward one to Pano and he will post.
Bottom line is you can spend less money for a couple of cheap 15's and do way better. You can use a plate amp and get it to work well, but after spending $160 you have to spend an additional $125 to get it to perform. Not a good deal. Plus the added complexity and weight.
Attachments
Should we consider 2 GRS per side to increase efficiency and power handling? Perhaps the increased cost of the extra driver can be offset by the lower inductor?
Thanks,
Duc
Dual GRS 15
I have mocked up a dual 15 version. And as you point out, the added cost of the second 15" is partially offset buy the lower cost of the smaller inductor.
However, there is still about a $ 30 cost increase per pair of speakers and you have a 4. 6 ohm load which is not as amplifier friendly. Also, integration of the Vifa is not quite as good. There is a marginal efficiency increase and added power handling in the very low end. The biggest positive difference for the dual woofer version seems to be a bit more dynamics but at the cost of some degrading of lower midrange performance because of the distance between the lower woofer and Vifa. This can be corrected with crossover modifications, but this adds to cost and complexity. Over all the dual woofer system will not play any louder as you are limited by the Vifa's displacement.
I have mocked up a dual 15 version. And as you point out, the added cost of the second 15" is partially offset buy the lower cost of the smaller inductor.
However, there is still about a $ 30 cost increase per pair of speakers and you have a 4. 6 ohm load which is not as amplifier friendly. Also, integration of the Vifa is not quite as good. There is a marginal efficiency increase and added power handling in the very low end. The biggest positive difference for the dual woofer version seems to be a bit more dynamics but at the cost of some degrading of lower midrange performance because of the distance between the lower woofer and Vifa. This can be corrected with crossover modifications, but this adds to cost and complexity. Over all the dual woofer system will not play any louder as you are limited by the Vifa's displacement.
Anyone ever though about cheating? I use a reciever that has microphone calibration. It's called Audyssey MultEQ. It allows me to using cheap magnepan mmgw's on a baffle to get a perfect response from 120-20k with almost perfect integration with a 12" subwoofer even though the two mags are horribly matched. They sound so different with the calibration turned off the magnepan should be slapped in the face for selling them to me, but turn the calibration on and the system goes from crap to hi end. Seems like this may be the way to go for dipoles. Then again I might be losing a lot with all that processing. No passive crossover components though.
John I think your design is very cool because it's cheap and plug and play with it's crossover and yet it's a simple crossover design. Keep up the good work.
John I think your design is very cool because it's cheap and plug and play with it's crossover and yet it's a simple crossover design. Keep up the good work.
John .... really slick design.
I own a pair of the large heil amt's. Could a guy drop these into your original design (first pg of this thread) as a mid/tweet keeping everything else "as-is" (baffle size, passive xo, etc.)?
Thing is, I must use these heils in OB. You have demonstrated that finding the appropriate woofer, one that plays well up to 1.5khz, could be just the ticket for me (a simple 2-way solution).
Please list other woofers, regardless of size, you've found to have the "right stuff" as far as playing well into the 1.5k range. I wouldn't be opposed to having a pair of woofers per channel ... even if that meant a wide elevated panel (on stands as you've shown). I have the room and like max SPL at times. (marantz 2285B receiver would be driving it).
Thanks and GL with the commercial side of your designs!!
I own a pair of the large heil amt's. Could a guy drop these into your original design (first pg of this thread) as a mid/tweet keeping everything else "as-is" (baffle size, passive xo, etc.)?
Thing is, I must use these heils in OB.
You have demonstrated that finding the appropriate woofer, one that plays well up to 1.5khz, could be just the ticket for me (a simple 2-way solution). Please list other woofers, regardless of size, you've found to have the "right stuff" as far as playing well into the 1.5k range. I wouldn't be opposed to having a pair of woofers per channel ... even if that meant a wide elevated panel (on stands as you've shown). I have the room and like max SPL at times. (marantz 2285B receiver would be driving it).
Thanks and GL with the commercial side of your designs!!
AMT - OB thoughts
Thank you for your positive comments.
As for using the Heil AMT in a 2 way OB design, similar to the Manzanita? Yes this could be done, however it would require considerable crossover work. The original two versions of the Manzanita used monopole dome tweeters. So, the only rear (dipole) radiation was from the Peerless and it diminished rapidly above 1K or so. This, in combination with the crossover required for woofer OB Bass correction, created a broad droop in the forward midrange radiation. However, there was enough reflected energy and lower midrange output from the tweeters, when combined with the Peerless limited forward radiation, to fill things in at a typical listening distance. This provided a relaxed sound quality many like.
The latest version of the Manzanita using the Vifa TC9FD radiating in a dipole configuration is much closer to your design situation. Like the Vifa however, the AMT will need to be treated like a band pass driver to yield a flat response at the listening position. I remember when the Heil two way floor standing speakers came out. I was a dealer for them at the time. I never quite liked the presentation. Parts of the spectrum were very clear, others VERY congested. I now know why.
Heil used a reverse polarity crossover set up trying to fix an excess upper midrange issue. Didn't really work. The excess was coming via reflected rear wall energy. I heard and measured the same issue with the Vifa and Seas H-1597-08 8" full range. So like the Vifa, a crossover has to create a broad upper midrange, lower treble droop to sum acoustically flat at the listening position as well as provide a balanced power response. And, the AMT needs to be able to play flat down to around 500-800 Hz to be effective in a two way set up using large woofers. Then there is setting the output levels and all the rest to end up with a crossover - system configuration that would perform up to the Heil's ability.
As for woofers with the right combo of displacement and clean response up to and above 1.5 Khz, these are rare. Other than the Peerless, the only other woofer that comes to mind is the Seas H-1411 10". However, it would take 2 or 4 per channel and the H-1411 has become rather expensive at $140 each. This driver plays flat to 2Khz and has a near perfect 2nd order roll off. Excellent mid range too. What would be a neat design would to put the H-1411 in a sealed .8 QTC alignment and set the AMT on top with a midrange corrective crossover. Do what Heil tried to do 40 years ago, but correctly this time!!!
Thank you for your positive comments.
As for using the Heil AMT in a 2 way OB design, similar to the Manzanita? Yes this could be done, however it would require considerable crossover work. The original two versions of the Manzanita used monopole dome tweeters. So, the only rear (dipole) radiation was from the Peerless and it diminished rapidly above 1K or so. This, in combination with the crossover required for woofer OB Bass correction, created a broad droop in the forward midrange radiation. However, there was enough reflected energy and lower midrange output from the tweeters, when combined with the Peerless limited forward radiation, to fill things in at a typical listening distance. This provided a relaxed sound quality many like.
The latest version of the Manzanita using the Vifa TC9FD radiating in a dipole configuration is much closer to your design situation. Like the Vifa however, the AMT will need to be treated like a band pass driver to yield a flat response at the listening position. I remember when the Heil two way floor standing speakers came out. I was a dealer for them at the time. I never quite liked the presentation. Parts of the spectrum were very clear, others VERY congested. I now know why.
Heil used a reverse polarity crossover set up trying to fix an excess upper midrange issue. Didn't really work. The excess was coming via reflected rear wall energy. I heard and measured the same issue with the Vifa and Seas H-1597-08 8" full range. So like the Vifa, a crossover has to create a broad upper midrange, lower treble droop to sum acoustically flat at the listening position as well as provide a balanced power response. And, the AMT needs to be able to play flat down to around 500-800 Hz to be effective in a two way set up using large woofers. Then there is setting the output levels and all the rest to end up with a crossover - system configuration that would perform up to the Heil's ability.
As for woofers with the right combo of displacement and clean response up to and above 1.5 Khz, these are rare. Other than the Peerless, the only other woofer that comes to mind is the Seas H-1411 10". However, it would take 2 or 4 per channel and the H-1411 has become rather expensive at $140 each. This driver plays flat to 2Khz and has a near perfect 2nd order roll off. Excellent mid range too. What would be a neat design would to put the H-1411 in a sealed .8 QTC alignment and set the AMT on top with a midrange corrective crossover. Do what Heil tried to do 40 years ago, but correctly this time!!!
For those Interested in the Ultra OB project
I have posted the base schematic for this project here:
The best affordable DIY open baffle loudspeaker I've listened to so far.
John
I have posted the base schematic for this project here:
The best affordable DIY open baffle loudspeaker I've listened to so far.
John
Unsolicited mini-review:
I've had my original Manzanitas running for a few years now.
I love them.
Right now, they are hanging from the ceiling, tilted and angled to point
to the listening position;
the rear radiation is damped by heavy window drapes.
The room that the Manzanitas play in is our small bedroom... about
15' by 20', in our log cabin.
My dipoles are very inefficient, yes they are, but they are more than
adequate in this small space.
My musical taste?
Try everything!
These speakers do very well on all my music, save for dubstep,
classical organ recitals and the like.
(I have other, more efficient speakers for the bass-heavy concert-level material.)
I'm temped to wax rhapsodic, to lapse into cliche-speak.
But I won't.
If you love dipoles and have a space that's friendly for their sound,
then you ought to consider this design.
I'm very happy that I built these.
Thank you, Mr. Bsuch.
----
-Steve
I've had my original Manzanitas running for a few years now.
I love them.
Right now, they are hanging from the ceiling, tilted and angled to point
to the listening position;
the rear radiation is damped by heavy window drapes.
The room that the Manzanitas play in is our small bedroom... about
15' by 20', in our log cabin.
My dipoles are very inefficient, yes they are, but they are more than
adequate in this small space.
My musical taste?
Try everything!
These speakers do very well on all my music, save for dubstep,
classical organ recitals and the like.
(I have other, more efficient speakers for the bass-heavy concert-level material.)
I'm temped to wax rhapsodic, to lapse into cliche-speak.
But I won't.
If you love dipoles and have a space that's friendly for their sound,
then you ought to consider this design.
I'm very happy that I built these.
Thank you, Mr. Bsuch.
----
-Steve
This is really special, so simple, so cheap. LOVE the XO design. I don't even need to hear it to know it's awesome. You should clone yourself John, the world needs more of this kind of thing.
I'm not ready to build these yet because I'm in the middle of a Pensil 10.2 build but I'm getting a pair of those Vifa's before PE stops selling them.