AudioCircle
Audio/Video Gear and Systems => Open Baffle Speakers => Topic started by: Horizons on 20 Oct 2014, 08:33 pm
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I never stayed with my various OBs because I couldn't get the detail I wanted with compression drivers. However, I have been listening to Heil AMTs crossed over at 24 db/octave at 1 K and these are truly amazing dipole tweets.
So, I am thinking about an AMT based OB with either 2 15 Alphas crossed at 1K or two 12s. 12s might work better crossed that high. Any recs on a pair of 12s that give you that magic live OB sound and are clean to 1 kHz? I like and have used the Alphas but I already have two subs (ML sealed) and thinking that maybe there is something better to mate with the AMTs.
Or twin Betsy's??
TIA
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If you are going to invest in a set of Heil AMT's and plan to cross that high, take a look at some of the LF Altec Lansing drivers reworked by Great Plains Audio. Your woofers will be reproducing some very critical fundamentals and you will want something that is very articulate to match the speed and clarity. http://www.greatplainsaudio.com/woofers.html
As an alternative, you may want to contemplate a 3-way design, using a small midrange coupler between the LF and HF sections. The Hestia V is an example which uses the Dayton AMT and a mid-coupler, albeit crossed much higher.
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If you are going to invest in a set of Heil AMT's and plan to cross that high, take a look at some of the LF Altec Lansing drivers reworked by Great Plains Audio. Your woofers will be reproducing some very critical fundamentals and you will want something that is very articulate to match the speed and clarity. http://www.greatplainsaudio.com/woofers.html
As an alternative, you may want to contemplate a 3-way design, using a small midrange coupler between the LF and HF sections. The Hestia V is an example which uses the Dayton AMT and a mid-coupler, albeit crossed much higher.
Matevana,
where would you think the best place would be, to cross over the Heil AMT's ?
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You are going to need a mid bass coupler of some sort. There is going to be too big of a frequency hole between the Heil and the Alpha. Just for grins, take a look at Ed Schilling's Horns. He uses a Fostex for the mid bass. The AMT is series wired to the mid. I know this combo works well. All you would have to do is figure out where to bring in the Alphas. A starting point anyway.
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Start reading here.
http://www.hawthorneaudio.us/forums/viewtopic.php?f=2&t=5002&start=15
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Matevana,
where would you think the best place would be, to cross over the Heil AMT's ?
In all fairness I have only worked with the Dayton AMTPro (dipoles) which are licensed by Heil but have different properties. I preferred them crossed much higher, in the area of 6-7k with a more shallow slope (6-12dB per octave). I use a Seas MU10 (4' midrange) which couples the AMT to the LF driver. Crossing higher will typically yield more balanced waterfall plots, so it also depends what your overall design goals might be. Hope this helps.
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Thanks for the info. The Hawthorne thread is interesting with an Alpha 15 crossed to the AMT at 5K. I already own a pair of AMTs and a pair of Ed's horns. Its a great match but I miss the OB sound of my old Emerald Physics clones. Those had an OB pair of Alphas with a compression driver crossed at 1K. I have heard the Alpha's crossed at 1 K and never had a problem with them. My current AMT/horns use Ed's series xover and are roughly crossed around 1K too. I'm very tempted to just try 2 15-inch Alphas on a simple OB and electronically crossed to the AMT around 1 K. I don't think you get the magic of the AMT if crossed at 5KHz.
Very helpful responses.
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Wild Burro Audio Betsy 8" with bass help?
http://www.randallrash.com/New_Loudspeakers_part9.html
http://www.wildburroaudio.com/speakers.php
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Wild Burro Audio Betsy 8" with bass help?
http://www.randallrash.com/New_Loudspeakers_part9.html
http://www.wildburroaudio.com/speakers.php
Like that set up...!
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If you are going to invest in a set of Heil AMT's and plan to cross that high, take a look at some of the LF Altec Lansing drivers reworked by Great Plains Audio. Your woofers will be reproducing some very critical fundamentals and you will want something that is very articulate to match the speed and clarity. http://www.greatplainsaudio.com/woofers.html
That is exactly what I did. Altec 416s reworked by GPA.
I cross 1st order @ 1,000Hz 500Hz on the woofers, 3rd order @ 1,200Hz to the Heils.
Big cabinets ~10 cu/ft made of Baltic Birch plywood
Edit: Sorry, didn't realize this is the OB forum.
(http://i1161.photobucket.com/albums/q506/sebrof2000/IMG_2836_zpscb2b6596.jpg)
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That is exactly what I did. Altec 416s reworked by GPA.
I cross 1st order @ 1,000Hz on the woofers, 3rd order @ 1,200Hz to the Heils.
Big cabinets ~10 cu/ft made of Baltic Birch plywood
Edit: Sorry, didn't realize this is the OB forum.
(http://i1161.photobucket.com/albums/q506/sebrof2000/IMG_2836_zpscb2b6596.jpg)
sebrof,
I have always wondered how your set up sounds. looks really interesting...!
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Here is an application correction for using Heil AMT drivers. As Ed is banned, and I don't recall why, he contacted me via email.
Quote from Ed Schilling of the Horn Shoppe:
Hey Steve, I saw a post at AC by Horizons that is in error. Since I have been banned I can not correct it. The xover on the Horn/Heils is around ~4k not 1k. A 6 db slope @1K with a Heil will result in thermal runaway and melted diaphragms. At that freq. in order to have any semblance of power handling and low distortion at least 18db must be used. I could care less who believes this......but I hate to see my buddies melt a set of diaphragms due to misinformation. Now, if one listens to "little girls and guitars" at very low volumes it may be possible to avoid melt down BUT.....even then they can be damaged if played long enough at what most consider "normal volume".
I just would like to add that properly used, the Heil is an excellent driver. I have not found any of the newer AMT drivers to be in the same league
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I've never tried these drivers/brand, but it almost looks like you could use one or two of these with a Heil AMT.
Crossover at 3.5k...not sure. But, the price is right.
http://www.mcmelectronics.com/product/MCM-AUDIO-SELECT-55-2981-/55-2981
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You are going to need a mid bass coupler of some sort. There is going to be too big of a frequency hole between the Heil and the Alpha. Just for grins, take a look at Ed Schilling's Horns. He uses a Fostex for the mid bass. The AMT is series wired to the mid. I know this combo works well. All you would have to do is figure out where to bring in the Alphas. A starting point anyway.
[/quote
Where do I go to see Ed Shillings horns ?
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I appreciate Ed setting the record straight on his crossover frequency.
Just for fun, I tried Randy's approach on Hawthorne Audio with an OB with the Alpha and ATM with a 5 KHz, 6 db passive XO. I was stunned with how good this sounds, especially with the Alpha running that high. I was intending on going active around 1KHz/24 db but this passive first order approach sounds like live music.
My next question is whether or not to baffle mount the AMT or just stack on top like I am currently doing. That AMT is just an amazing driver.
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I, who has owned a pr. of the original ESS heil units for 30+ years and I'm still using them. I don't
buy Ed S. advise as to what they can handle as far as X-over points. I use them in a active/ triamp
system crossed at 1000hz/18db and have never melted them. Don't know where he is coming up
with his numbers.
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I, who has owned a pr. of the original ESS heil units for 30+ years and I'm still using them. I don't
buy Ed S. advise as to what they can handle as far as X-over points. I use them in a active/ triamp
system crossed at 1000hz/18db and have never melted them. Don't know where he is coming up
with his numbers.
The way I read Ed's information he is saying 1,000 Hz with 18db slope is fine, which is what you say you are using. So I think you and Ed agree, actually.
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I believe the manufacturer, ESS, recommends a 1K crossover.
(Heil AMT is licensed exclusively to ESS, not sure if it is made in house or not.)
I also believe they sell a set of two way speakers that they manufacturer, and they cross them at 1K. And I've not heard any issues from the owners of there manufactured speakers. :dunno:
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I never stayed with my various OBs because I couldn't get the detail I wanted with compression drivers. However, I have been listening to Heil AMTs crossed over at 24 db/octave at 1 K and these are truly amazing dipole tweets.
So, I am thinking about an AMT based OB with either 2 15 Alphas crossed at 1K or two 12s. 12s might work better crossed that high. Any recs on a pair of 12s that give you that magic live OB sound and are clean to 1 kHz? I like and have used the Alphas but I already have two subs (ML sealed) and thinking that maybe there is something better to mate with the AMTs.
Or twin Betsy's??
TIA
I've researched this extensively. Because it was something I wanted to try myself. The Alphas are perfect, qt's, OB, etc, etc, but one thing I don't see right. Heil recommends an 8 ohm woofer in a two way set up. If you could get the same speaker (2, 15" Alphas) in 4 ohms, it would work great. In series. Or use just one 15" Alpha.
I wanted to do a WTW set up using the Heil AMT. But, can't find the right 12 or 15 inch, 4 ohm woofer that has the higher QT rating for an OB setup.
:scratch:
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For various reasons, I settled on the following for my latest OB experiment:
One Alpha 15A
One Dayton AMTPRO-4
Baffles are ~ 20" wide, 42 inches tall. They are tapered so they are ~12 inches wide at the top of the panel.
Currently using a simple coil/cap arrangement with the drivers rolling in/out around 4-5 KHz.
With this arrangement, I guess I just got lucky with the efficiency/xover points/slopes and the drivers match well with no need for padding down the AMT.
I can post pix if anyone is interested but so far, I am very impressed with how good these sound. I am still using a sealed ML sub for < 50 Hz. Setting up a local listening panel soon to A/B these with Maggies, Logans, and a few other single driver setups. You really need to discount the pride factor when you build your own. But right now I would say that these are Maggie killers. All of the open and boxless sound of Maggies with much more bass, efficiency, depth, dynamics, and better and more extended highs.
I have also been trying to determine if the AMTPRO driver is as good as the great Heil AMT. I'm still not sure, but it is close.
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For various reasons, I settled on the following for my latest OB experiment:
One Alpha 15A
One Dayton AMTPRO-4
Baffles are ~ 20" wide, 42 inches tall. They are tapered so they are ~12 inches wide at the top of the panel.
Currently using a simple coil/cap arrangement with the drivers rolling in/out around 4-5 KHz.
With this arrangement, I guess I just got lucky with the efficiency/xover points/slopes and the drivers match well with no need for padding down the AMT.
I can post pix if anyone is interested but so far, I am very impressed with how good these sound. I am still using a sealed ML sub for < 50 Hz. Setting up a local listening panel soon to A/B these with Maggies, Logans, and a few other single driver setups. You really need to discount the pride factor when you build your own. But right now I would say that these are Maggie killers. All of the open and boxless sound of Maggies with much more bass, efficiency, depth, dynamics, and better and more extended highs.
I have also been trying to determine if the AMTPRO driver is as good as the great Heil AMT. I'm still not sure, but it is close.
I've heard very good things about the AMT-PRO.
I am thinking about a similar setup, just narrowing my decision down on which drivers to get. I was thinking about a WTW or TWW set up. I'm almost there.
Pics, if you have any...?
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For various reasons, I settled on the following for my latest OB experiment:
One Alpha 15A
One Dayton AMTPRO-4
Baffles are ~ 20" wide, 42 inches tall. They are tapered so they are ~12 inches wide at the top of the panel.
Currently using a simple coil/cap arrangement with the drivers rolling in/out around 4-5 KHz.
With this arrangement, I guess I just got lucky with the efficiency/xover points/slopes and the drivers match well with no need for padding down the AMT.
I can post pix if anyone is interested but so far, I am very impressed with how good these sound. I am still using a sealed ML sub for < 50 Hz. Setting up a local listening panel soon to A/B these with Maggies, Logans, and a few other single driver setups. You really need to discount the pride factor when you build your own. But right now I would say that these are Maggie killers. All of the open and boxless sound of Maggies with much more bass, efficiency, depth, dynamics, and better and more extended highs.
I have also been trying to determine if the AMTPRO driver is as good as the great Heil AMT. I'm still not sure, but it is close.
From what I have researched and what I know about that AMTPRO and those Alpha 15A's. That simple design is going to sound very nice. I wouldn't be surprised if they sound incredible. I am just completely surprised how well OB speakers sound.
OB speakers are just one of those things that you have to hear for your self to believe. And from my own experimenting/experience, I won't go back to a box speaker, ever. :D
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My "all Hawthorne" setup has the Hawthorne AMT-500 crossed at 500 Hz and two 15" Hawthorne SSI mid-drivers in MTM configuration and two 15" Hawthorne Augies biamped on separate towers PER side. Sounds sublime...
The AMT dipole is a wonderful choice.
(http://www.audiocircle.com/image.php?id=117708)
John
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Hi John,
may I know with what amplifiers you drive those nice Hawthorn speakers?
Guy 13
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Guy,
Thanks for the question. I used to use either a modified Bottlehead Stereomour 2A3 amp (3.5 watts) or modified Bottlehead Paramount 300B mono blocks (8 watts) when I had it "not" MTM (just MT) but after making the move to MTM, I find I have a difficult load...the efficiency is still nearly 100 dB but the load is complex. The picture shows the BH 300B amps. I have two different crossovers, one for the MT and one for the MTM configuration. The drivers stay in the baffles, just the crossovers switch (the crossovers are mounted on nice plinths that are separate from the speakers and are pre-wired with Grover Huffman "umbilicals" to connect to the drivers).
With the MTM configuration, I have Quicksilver Silver 88 mono blocks and a Pass Labs XA-30.5 amp. Both are excellent but I find the Pass Labs XA-30.5 is in the rig nearly all the time these days.
John
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Guy,
Thanks for the question. I used to use either a modified Bottlehead Stereomour 2A3 amp (3.5 watts) or modified Bottlehead Paramount 300B mono blocks (8 watts) when I had it "not" MTM (just MT) but after making the move to MTM, I find I have a difficult load...the efficiency is still nearly 100 dB but the load is complex.
So I have Quicksilver Silver 88 mono blocks and a Pass Labs XA-30.5 amp. Both are excellent but I find the Pass Labs XA-30.5 is in the rig nearly all the time these days.
John
Thanks John.
Guy 13
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Guy,
I modified my post a little to give more detail...
I really enjoy your posts, by the way. I just wanted to tell you that since we have not spoken with each other much.
John
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John,
The discussion about open baffle speakers is pretty controversial and well debated. I have tried a Eminence Delta 15FLA speaker in a flat baffle. (No H/U/wings, etc, etc.) And it produces wonderful low end, I'm not sure how, but it sounds wonderful.
I also wanted to complement you on your finish, the rich darker finish looks great.
V....
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OB low end is not boomy...so what it misses in the lowest octave and in pressure, it makes up for in musicality, in my opinion. There is a different loading of the room than with a box sub. I've posted this link recently elsewhere but I think it covers the "why" as well as anything I've read.
http://www.linkwitzlab.com/rooms.htm (http://www.linkwitzlab.com/rooms.htm)
By far the perceptually most uniform response in the range below 200 Hz is obtained with an open-baffle, dipole or figure-of-eight radiating source. Because of its directionality, the dipole excites far fewer room resonances than an omni-directional source. The measured room response is not necessarily any smoother than that for an omni-directional source. But the perceived difference in bass reproduction is startling at first, because we are so used to hearing the irregular and booming bass of the typical box speaker in acoustically small rooms. Quickly one learns to recognize the distortion of this combination and it becomes intolerable.
Thank you for the nice comment on the finish. Mike (Woodsage) in Seattle made those for me out of solid Sapele. They are quite thick. The photo does not do them justice...
John
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Well, I finally gave up on the AMTPRO. It is a really nice driver but the Heil AMT has a more extended top end and just sounds more real. I am also back to biamping, using dbx analog LR4 at ~1400 Hz. Sounds wonderful. I will probably use the AMTPRO for a pair of rear channels.
I can't imagine ever going back to a box speaker. And there is no longer the need to compromise the bass with a planer driver like the Maggie. Cones free of boxes sound much better than Maggies IMO.
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Thanks for the info. The Hawthorne thread is interesting with an Alpha 15 crossed to the AMT at 5K. I already own a pair of AMTs and a pair of Ed's horns. Its a great match but I miss the OB sound of my old Emerald Physics clones. Those had an OB pair of Alphas with a compression driver crossed at 1K. I have heard the Alpha's crossed at 1 K and never had a problem with them. My current AMT/horns use Ed's series xover and are roughly crossed around 1K too. I'm very tempted to just try 2 15-inch Alphas on a simple OB and electronically crossed to the AMT around 1 K. I don't think you get the magic of the AMT if crossed at 5KHz.
Very helpful responses.
After researching and working on a set of OB speakers myself, I would say that your set up would work nicely.
I am using a ribbon tweeter (G1 Aurum Cantus) crossed at 2000hz, with a 10" Morel woofer. Those Morels (made in Israel.) are the same model that www.pureaudioproject.com uses, and they are hard working and very nice. I use one amp for the G1/Morel and I have another amp driving an Eminence Delta 15FLA woofer to support the low end. (The 15FLA has a low pass filter of 180hz.)
My system isn't exactly like yours, but you get the idea. I experimented with a x-over at 1600hz, because the Morel has a bit of a spike at that frequency, but it just worked/sounded better at 2khz. Both drivers, G1/Morel have very accurate specs available, unlike some manufacturers.
Did you end up trying two woofers or did you stay with one ?
V....
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After researching and working on a set of OB speakers myself, I would say that your set up would work nicely.
I am using a ribbon tweeter (G1 Aurum Cantus) crossed at 2000hz, with a 10" Morel woofer. Those Morels (made in Israel.) are the same model that www.pureaudioproject.com uses, and they are hard working and very nice. I use one amp for the G1/Morel and I have another amp driving an Eminence Delta 15FLA woofer to support the low end. (The 15FLA has a low pass filter of 180hz.)
My system isn't exactly like yours, but you get the idea. I experimented with a x-over at 1600hz, because the Morel has a bit of a spike at that frequency, but it just worked/sounded better at 2khz. Both drivers, G1/Morel have very accurate specs available, unlike some manufacturers.
Did you end up trying two woofers or did you stay with one ?
V....
Hi Bladesmith and everybody,
I just joined AudioCircle, after our Trio10 MundorfAMT made it to AudioCircle 'Best of RMAF 2015' and saw this thread... so this is my first post here...
The Morel 10" you have do look the same but have different parameters from our PAP1075. These were modified by Morel specifically for Open Baffle, e.g. Qts-1.14, Xmax: +/-4.75mm, see compete spec:https://drive.google.com/open?id=0B36Kyv2xZFCtYWhmVjA0a0M4Z1U (https://drive.google.com/open?id=0B36Kyv2xZFCtYWhmVjA0a0M4Z1U).
These woofers play powerful, fast and clean deep bass and at the same time are sweet mid performers that can be taken up to 6.5khz and they are used by us in all our Trio10 models.
quote: "these speakers had it all – superb soundstage, perfect tonality, super open spacious sound that just destroys the walls in the room, all things that great open baffle speakers give you. But, what set this system apart was the laser like focus and lack of “misty” presentation almost every OB speaker has. Plus BASS SLAM. I know you never thought you’d see the words bass slam and Open Baffle ever uttered together. But there it is. I am an OB lover, it’s what I’ve run in my home system for years and years and so I’m a bit jaded about them. But this room raised the bar substantially over every other available OB system I’ve heard. Massive congrats to them for this achievement.”, Audio Circle, PEZ, Best of RMAF 2015, http://www.audiocircle.com/index.php?topic=137753.0
Trio10 MundorfAMT with PAP1075, OB 10" woofers and Mundorf AMT23D6.1
(http://www.audiocircle.com/image.php?id=130386) (http://www.audiocircle.com/image.php?id=130387)
(http://www.audiocircle.com/image.php?id=130390)
Trio10 MundorfAMT Crossovers
These woofers easily integrate with Heil AMT but we didn't design the XO for this particular configuration yet. Bi amping is no issue though !
Trio10 HeilAMT Configuration
(http://www.audiocircle.com/image.php?id=130391)
Re the thread title: 'OB with Twin Alphas and Heil AMT'.
We integrated the Heil AMT with our OB-A15neo woofers, that are our custom Eminence upgrades to the Alpha15a http://www.pureaudioproject.com/product/15inch-open-baffle-bass-woofers/ (http://www.pureaudioproject.com/product/15inch-open-baffle-bass-woofers/), since these upgraded drivers sound and play well up to 1khz (and even a bit more). We offer the Trio15 HeilAMT as a complete product and offer DIYers the OB-A15neo woofers, the Frames and woodwork plans. see our web www.pureaudioproject.com
Trio15 HeilAMT
(http://www.audiocircle.com/image.php?id=130385)
(http://www.audiocircle.com/image.php?id=130389) (http://www.audiocircle.com/image.php?id=130388)
(http://www.audiocircle.com/image.php?id=130384)