well, the old story
It sounds terrific, then changed, sounding better, and changed again, unendflessly
Honestly, it looks like a complete frustration to me, and way too expencive to buy, sorry
But good entertainment
0-60 mph in less than 1 ms?
Seriously: its delivers great sound down to approx 30 Hz. I could use all the hifi terms like "dynamic, well defined, punchy" and so on to describe it. I think you know what I mean... its the best bass I've heard so far.
Below 30 Hz I sometimes get excursion problems, so an other pair of 21" H-baffles is what I want for Christmas. 
...
Below 30 Hz I sometimes get excursion problems, so an other pair of 21" H-baffles is what I want for Christmas.
Does that 'sometimes' mean when the dinosaur is coming out?
I found 3-channel configuration helps "filling" the room significantly. I've tried turning off my center sub and boosted the main channels some more dB to level the response. Even with similar measured results, by ears, 3-ch bass is just doing much better than 2-ch. The advantages in senses of room-filling, effortless, extension are very obvious in 3-ch bass.
So, maybe adding another 21" would be helpful enough while the forth would be only marginal by comparison.
Dont sound too far off to me. They can play very loud bass unless there is something happening in the 25 Hz area. If I'm not mistaking, 28 Hz is the "knee" where things starts to go wrong with the cone excursion. If I add two more H-baffles, I will get 6 dB higher max SPL, and that will be enough for me.
Hi,
In my case, I only run my center sub in mono. The other 2 are actually main channels and the woofers are covering higher, so they remain stereo.
I'm not familiar with the music you mentioned, just realize they are electronic music by googling. Oh yes there're very deep bass notes by the synthesizers, no doubts. I've also found there're many 'noises' in the bottom octave in all kinds of live concert records. Sometimes they make the presentations more 'life-like', sometimes troublesome.
In my case, I only run my center sub in mono. The other 2 are actually main channels and the woofers are covering higher, so they remain stereo.
I'm not familiar with the music you mentioned, just realize they are electronic music by googling. Oh yes there're very deep bass notes by the synthesizers, no doubts. I've also found there're many 'noises' in the bottom octave in all kinds of live concert records. Sometimes they make the presentations more 'life-like', sometimes troublesome.
Yes - the only music I have which create problems for the woofers is electronic music.
There's a lot of low frequency enviromental noise on many classical recordings, especially live recordings. A great example is the Gardiner Bach Canatas number 15 from New York. You can really sense that outside the recording venue is one of the worlds largest cities!
Its this one:
Bach Cantata Series
If you dont have it yet, run out and buy it now!!
There's a lot of low frequency enviromental noise on many classical recordings, especially live recordings. A great example is the Gardiner Bach Canatas number 15 from New York. You can really sense that outside the recording venue is one of the worlds largest cities!
Its this one:
Bach Cantata Series
An externally hosted image should be here but it was not working when we last tested it.
If you dont have it yet, run out and buy it now!!
Stig Erik,
That's very innovative work
So, the big problem in the box; acoustical and mechanical resonances
A link, HAUPT
Showing a graph of the acoustic effects on the box
and some techniques to reduce the baffle resonances
**** A speech in the link below
Issues in speaker design - 2
''An early example of a box loudspeaker where a KEF B110 midrange/woofer driver magnet is clamped to a support structure. The clamp can be tightened from the outside of the box. The basket rim is floating.
Often the effects due to driver mounting are deemed to be of secondary importance to the overall sound quality of a loudspeaker. They are usually costly to remedy. They cannot be ignored when the goal is to design a loudspeaker of the highest accuracy.''
**** A Preliminary report about Loudspeaker Driver De-Coupling by A. Jones, Pioneer-TAD
conclusion
The results show a large reduction in cabinet vibration in the de-coupled condition, with improvements in the order of >20dB.
This confirms that the dominant excitation source is mechanical and not acoustical.
Experimental results of de-coupling experiments confirm that
• Diaphragm motion is minimally affected by de-coupling the drive unit from the cabinet
• Magnet motion, the “ground reference” for the cone motion, is better behaved when the drive unit is de-coupled
• Cabinet vibration is substantially reduced with a de-coupled drive unit
• Preliminary listening tests indicate a preference for the de-coupled drive unit
That's very innovative work
So, the big problem in the box; acoustical and mechanical resonances
A link, HAUPT
Showing a graph of the acoustic effects on the box
and some techniques to reduce the baffle resonances
**** A speech in the link below
Issues in speaker design - 2
''An early example of a box loudspeaker where a KEF B110 midrange/woofer driver magnet is clamped to a support structure. The clamp can be tightened from the outside of the box. The basket rim is floating.
Often the effects due to driver mounting are deemed to be of secondary importance to the overall sound quality of a loudspeaker. They are usually costly to remedy. They cannot be ignored when the goal is to design a loudspeaker of the highest accuracy.''
**** A Preliminary report about Loudspeaker Driver De-Coupling by A. Jones, Pioneer-TAD
conclusion
The results show a large reduction in cabinet vibration in the de-coupled condition, with improvements in the order of >20dB.
This confirms that the dominant excitation source is mechanical and not acoustical.
Experimental results of de-coupling experiments confirm that
• Diaphragm motion is minimally affected by de-coupling the drive unit from the cabinet
• Magnet motion, the “ground reference” for the cone motion, is better behaved when the drive unit is de-coupled
• Cabinet vibration is substantially reduced with a de-coupled drive unit
• Preliminary listening tests indicate a preference for the de-coupled drive unit
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Reports from other people I know that have tried decopled/suspended drivers without baffles are that they're totally amazed by the lack of coloration!
I'm quite sure that paying attention to decoupling can improve box speakers as well, but you'll never get rid of the delayed energy inside the box completely. An other thing is that I think its easier to get good off-axis response with a dipole design.
I think I've found the drivers I want to use for the main dipole. The next thing up is to improve a bit on them. The Excel drivers have very stiff, but light magnesium chassi, which rings quite a lot. I will try do damp a little here with bitumen sheets.
For the bass there will be four 21" H-baffles for sure. Two is just not enough!
In time I will build a "finished" version of all this that looks a lot better that the current prototype speaker of course.
Here's a new picture. The only thing new is the amplifiers you can see on the floor behind the main dipoles....
An externally hosted image should be here but it was not working when we last tested it.
Hi Stig,
one quick question. I follow this thread with great interest, because I am open baffle fan, built quite a few of them, but never baffle-less speakers. I am just afraid of too much equalization needed due to too much cancellation.
So here is my question: in order to prevent cancellation, yet not to have speakers mounted on the baffle itself, what if there would be baffle attached to your frame? Just approaching the drivers, not touching them really, maybe some soft suspension between.
one quick question. I follow this thread with great interest, because I am open baffle fan, built quite a few of them, but never baffle-less speakers. I am just afraid of too much equalization needed due to too much cancellation.
So here is my question: in order to prevent cancellation, yet not to have speakers mounted on the baffle itself, what if there would be baffle attached to your frame? Just approaching the drivers, not touching them really, maybe some soft suspension between.
You certainly could give that a try.
Make sure you do your sealing as soft as can be in order to keep the "leakage path" as low energy transmitting as possible
Michael
+30 dB at 25 Hz is insane! .... that's why I am still stuck with closed box woofers, lets forget the woofers for the moment, lets talk about 200Hz up...
I understand your rational about off-axis response and dipole peak and higher crossover points, and no baffle vibration, its all compromises...I am just trying to imagine what the outcome would be if the speaker was mounted on some pole by the magnet, not attached to the baffle, the baffle would be quite large, hence little cancellation, baffle would be softly suspended away from vibration, so clean open baffle sound, baffle peak would be shifted low enough...how would the off-axis response looked like?
.... that's why I am still stuck with closed box woofers, lets forget the woofers for the moment, lets talk about 200Hz up...I understand your rational about off-axis response and dipole peak and higher crossover points, and no baffle vibration, its all compromises...I am just trying to imagine what the outcome would be if the speaker was mounted on some pole by the magnet, not attached to the baffle, the baffle would be quite large, hence little cancellation, baffle would be softly suspended away from vibration, so clean open baffle sound, baffle peak would be shifted low enough...how would the off-axis response looked like?
Reports from other people I know that have tried decopled/suspended drivers without baffles are that they're totally amazed by the lack of coloration!
I totally agree.
The freedom of (additional) coloration simply is second to none.
The concept of suspending a speaker on a swing and omitting any baffle is a wonderful combination
I have done it also with my small NEO3 horn and a nude Peerless 12" as a two way - correcting for the dipole loss with a simple inductor in series with the 12" and it works amazingly well given the extreme low investment.
New AMPs or new housing?
Michael
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I sadly didn't get ready over Christmas, but actually am working on this - If you have some patience I might come up with a comparison for complete nude 12" on a swing and 12" in baffle - both on swing. Most certainly I will cut the hole in the baffle with some play only and not use any sealing
Michael
I've been thinking along these lines as well, specifically an Orion type speaker with a minimal baffle and lower cost drivers than what Erik's using. This would be a four way but bit more accessible due to lower driver cost. Latest concept sketch attached; it starts out as a no baffle at high frequency and transitions to an H frame sub. From the top the drivers would be something like BG Neo3 PDRW, BG Neo8, Peerless 830884 (8" woofer), 830668 (10" sub), and 830669 (12" sub) with crossovers around 2kHz, 700Hz, and 175Hz.
The BG magnetostats are light enough attaching them to the minimal support frame that would hold them above the 8" shouldn't be a problem. The woofers would all be magnet mounted to the blades behind them---it's not clear from the sketch but the 8" would have a separate support from the subwoofers---and the blades isolation mounted to a plinth.
The BG magnetostats are light enough attaching them to the minimal support frame that would hold them above the 8" shouldn't be a problem. The woofers would all be magnet mounted to the blades behind them---it's not clear from the sketch but the 8" would have a separate support from the subwoofers---and the blades isolation mounted to a plinth.
Attachments
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There's approx 12 dB compensation for both the 5" and 8", which is not all that much. Both the 5" and 8" is crossed over below their dipole peak to get a clean off-axis respons, which would not be that good with baffles.
The 21" in H-baffle is EQ'ed a lot more... close to 30 dB @ 25 Hz!
WOW.
That much eq (I'd describe 12dB as quite a lot) sure brings thermal artifacts into question. Everything's a tradeoff, but if thermal issues are audible, then this system would certainly prove it!
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