Hi Mike,
I'll probably just end up designing something, both THAT Corp and Analog Devices make suitable mic amplifier chips with very good performance.
I used a number of these in MI amplifier balanced mic inputs with phantom power, even got the pop when enabling the phantom power down to something tolerable - depends on really good cmr in the input stage, and nothing to unbalance it.
I used to design electronics for a crummy little MI company hereabouts..
Pretty cool bunch of pix.. I think I have only seen one other pair of A7 with the "wings" installed.
Ali Baba and the den of horns....
I'll probably just end up designing something, both THAT Corp and Analog Devices make suitable mic amplifier chips with very good performance.
I used a number of these in MI amplifier balanced mic inputs with phantom power, even got the pop when enabling the phantom power down to something tolerable - depends on really good cmr in the input stage, and nothing to unbalance it.
I used to design electronics for a crummy little MI company hereabouts..
Pretty cool bunch of pix.. I think I have only seen one other pair of A7 with the "wings" installed.
Ali Baba and the den of horns....
Kevin,
Give some serious consideration to another way to get dispersion from your horns other than those nasty diffraction "venetian blinds". They almost always impart some sort of unpleasantness and it is also almost impossible to damp the metal itself... imho.
Consider ferrofluid in the diaphragms of both HF drivers.
Nice job on the Onkens.
Don't forget that with that placement in such a small room, you are doubtless getting some nice "room lift" and "corner gain"!
_-_-bear
Give some serious consideration to another way to get dispersion from your horns other than those nasty diffraction "venetian blinds". They almost always impart some sort of unpleasantness and it is also almost impossible to damp the metal itself... imho.
Consider ferrofluid in the diaphragms of both HF drivers.
Nice job on the Onkens.
Don't forget that with that placement in such a small room, you are doubtless getting some nice "room lift" and "corner gain"!
_-_-bear
Hi Bear,
The "venetian blinds" I am using are actually made of a heavy, non-resonant plastic, (they're 2308 clones, not the real thing) and using them is in my limited experience infinitely better sounding than not using them. Definitely something to think about though.
I can't imagine why I would want to use ferrofluid in my horn driver gaps, perhaps you can elaborate as to why I would want to? Their power handling is an order or two of magnitude higher than they will ever see, and I suspect that such a modification would destroy their resale value should I decide that I like something else better.
Thoughtful suggestions though..
The "venetian blinds" I am using are actually made of a heavy, non-resonant plastic, (they're 2308 clones, not the real thing) and using them is in my limited experience infinitely better sounding than not using them. Definitely something to think about though.
I can't imagine why I would want to use ferrofluid in my horn driver gaps, perhaps you can elaborate as to why I would want to? Their power handling is an order or two of magnitude higher than they will ever see, and I suspect that such a modification would destroy their resale value should I decide that I like something else better.
Thoughtful suggestions though..
Umm, I just re-read the Bear's post, he called my room "small"
Perhaps it's small by some standards, but the actual dimensions are 11.5 feet by 18 feet or 24 feet depending on which part of the back of the room you measure to. The ceiling height is a little under 7 feet which is the only real problem with this room.
The speakers aren't quite in the corners of the room despite appearances, and are themselves nearly 30" wide.
Treatment is minimal, just the carpet and acoustic tile on the ceiling, at the spls I usually listen at the room is lively, but not excessively reverberant. (There's a lot of cr*p in the way..LOL)
The woofers are breaking in as I write this, loud Depeche Mode. Sounds good..
Perhaps it's small by some standards, but the actual dimensions are 11.5 feet by 18 feet or 24 feet depending on which part of the back of the room you measure to. The ceiling height is a little under 7 feet which is the only real problem with this room.
The speakers aren't quite in the corners of the room despite appearances, and are themselves nearly 30" wide.
Treatment is minimal, just the carpet and acoustic tile on the ceiling, at the spls I usually listen at the room is lively, but not excessively reverberant. (There's a lot of cr*p in the way..LOL)
The woofers are breaking in as I write this, loud Depeche Mode. Sounds good..
kevinkr said:
Ferrofluid:
- reduced distortion
- smoother freq response
- usually improved high end extension & flatness
- better damping
No other reasons I can think of?
It will have no effect on the resale value, since you can wick it out and clean off any residue. That is, if you are careful and have a degree of skill...
Plastic, being "non resonant" seems better, but then it is less stiff... another issue. I don't like this type of diffraction lens...
I'm merely relating my personal experience on these matters... as always: ymmv.
_-_-bear
Hi Bear,
Points well taken. Do you have any suggestions for a different type of diffraction lens I could try or an alternate approach to improving dispersion short of changing to a different style horn?
Early on I did try them without the diffraction lens and they were extremely beamy without them. Very, very obvious.
I'm always willing to try something different in the quest for better sound.
Points well taken. Do you have any suggestions for a different type of diffraction lens I could try or an alternate approach to improving dispersion short of changing to a different style horn?
Early on I did try them without the diffraction lens and they were extremely beamy without them. Very, very obvious.
I'm always willing to try something different in the quest for better sound.
Kevin,
Can't say what sort of lens might be better.
I don't favor lenses for HF horns in general.
Consider a larger horn, a multicell, or larger single cell tractrix or similar expansion?
Some have been pushing the "conical" horn lately, but I remain quite skeptical regarding their performance and claims. That could change if I heard one that was simply terrific. And, ya gotta admit they don't require "rocket science" to build!
Personally, I use ~250-300hz horns and large format drivers. I don't like to xover @ 500Hz and up at all.
There are some tradeoffs with multicells, but I feel that the sound is mostly a function of the driver over the geometry... getting a great driver is non-trivial though.
At present, I think that the best sound is likely to come from a single cell horn over a multicell...
...it is always worth looking at what Western Electric did for their theater horns, and looking at the WE555 driver - back to the original specs and published articles... there are examples of this stuff on the web too.
One expects that with a single cell horn that you'd get a "problem" with the on axis vs. off axis response - and there is one to some extent, but I think that a little bit of clever thought and application in the design can overcome a whole lot of that issue - IF one finds it objectionable, which is usually not the case... (keep in mind your horn is *designed* to have a diffraction lens on it - it's a foreshortened horn!)
Also look at the Geddes and Peavey "eliptical waveguide" designs - they point the way to some newer expansions that change the polar response concerns too...
_-_-bear
Can't say what sort of lens might be better.
I don't favor lenses for HF horns in general.
Consider a larger horn, a multicell, or larger single cell tractrix or similar expansion?
Some have been pushing the "conical" horn lately, but I remain quite skeptical regarding their performance and claims. That could change if I heard one that was simply terrific. And, ya gotta admit they don't require "rocket science" to build!
Personally, I use ~250-300hz horns and large format drivers. I don't like to xover @ 500Hz and up at all.
There are some tradeoffs with multicells, but I feel that the sound is mostly a function of the driver over the geometry... getting a great driver is non-trivial though.
At present, I think that the best sound is likely to come from a single cell horn over a multicell...
...it is always worth looking at what Western Electric did for their theater horns, and looking at the WE555 driver - back to the original specs and published articles... there are examples of this stuff on the web too.
One expects that with a single cell horn that you'd get a "problem" with the on axis vs. off axis response - and there is one to some extent, but I think that a little bit of clever thought and application in the design can overcome a whole lot of that issue - IF one finds it objectionable, which is usually not the case... (keep in mind your horn is *designed* to have a diffraction lens on it - it's a foreshortened horn!)
Also look at the Geddes and Peavey "eliptical waveguide" designs - they point the way to some newer expansions that change the polar response concerns too...
_-_-bear
I am sorry that I have to disturb the Onken praising. My personal conclusion about this enclosure type is very negative, at least for the Ciare HX201. I got FAR better results (more bass, no comb filtering) with an old-school short-port BR of the same size (1/4 Sd port crossectional area, 2" port length). I didn`t expect this performance from a fullranger.
Bye bye slow FAST bass.
Bye bye slow FAST bass.
You're entitled to your opinion, but blanket statements such as yours aren't that helpful and can be somewhat insulting to someone like me who has invested heavily in the approach. You might have also noticed that I amongst others have invested considerable time, effort, and money in building these things. While not perfect they are a pretty big improvement in performance over the reflex speakers they replaced, and with continued tuning they just get... better.
There are a whole lot of reasons yours may not have worked well, port tuning, box volume, and pretty critically the damping factor / series source impedance driving the woofers.
Perhaps the qts of your driver was outside of the optimum range for this configuration, perhaps there were issues with the box tuning, all sorts of things that could be wrong.
I have plenty of bass, in far more in fact than the reflex based system they replaced.
I still have some work to do, but in general I am pleased with the results.
More later when I have time to respond.
There are a whole lot of reasons yours may not have worked well, port tuning, box volume, and pretty critically the damping factor / series source impedance driving the woofers.
Perhaps the qts of your driver was outside of the optimum range for this configuration, perhaps there were issues with the box tuning, all sorts of things that could be wrong.
I have plenty of bass, in far more in fact than the reflex based system they replaced.
I still have some work to do, but in general I am pleased with the results.
More later when I have time to respond.
Well Kevin, to be fair to el'OL he did say
"My personal conclusion about this enclosure type is very negative, at least for the Ciare HX201".
I would guess that the Onken type box is a difficult box to get right. Even a normal BR box is hard enough, heaven knows. It may be that the Onken is more sensitive to driver type.
My personal expierance with the Onken (done right) is that is sounds better than any moderately sized BR box.
The only bass boxes I ever heard that sonded better then the Onken were very large, many of them horn loaded. Like big Altec and JBL stuff or even the Onken W. Massive boxes. In a more reasonable size, the Onken always sounded best, to me.
"My personal conclusion about this enclosure type is very negative, at least for the Ciare HX201".
I would guess that the Onken type box is a difficult box to get right. Even a normal BR box is hard enough, heaven knows. It may be that the Onken is more sensitive to driver type.
My personal expierance with the Onken (done right) is that is sounds better than any moderately sized BR box.
The only bass boxes I ever heard that sonded better then the Onken were very large, many of them horn loaded. Like big Altec and JBL stuff or even the Onken W. Massive boxes. In a more reasonable size, the Onken always sounded best, to me.
el 'Ol, I did notice that you mentioned your experience as relating to the specific ciare driver. I've heard these are excellent drivers and I would have expected better performance than you experienced. Panomaniac had a good point in regards to your post. Building the Onken was the culmination of a 5 yr dream - I actually never thought I would do it. The driver was chosen for its excellent match to my desired enclosure size and for the fact that should I end up hating the Onken I would have a fall back configuration. (Those drivers were expensive.. LOL)
The driver I choose, the Iconic 165-8G was designed for horn loading and also had TS parameters that made it pretty ideal I thought for my Onken box. Driver FS is about 37Hz, but in this box in the interest of size and efficiency I tuned for right around 38Hz. There were several eminence drivers that looked interesting and would have been a lot less expensive...
Just wondering what was up with your cabinet design, your comment on the lack of extension is interesting.. I have noticed that this box design is really sensitive the amplifier damping factor, and small deviations seem to have a relatively drastic effect on the sound.
I am acquiring a measurement mic and designing and building a mic pre with phantom power. I plan to do a lot of measurements before I embark on finding the "final tuning" for my boxes.
I do know that my 3 ohm target source impedance is lower than that of the amplifier and inductor in the cross-over. I designed the amplifier and cross-over, and can fairly easily modify them to get the source impedance into the right range. Worst case I can use the 4 ohm tap on the amp, trade power for the lower source impedance..
Building the Onken was the culmination of a 5 yr dream - I actually never thought I would do it. The driver was chosen for its excellent match to my desired enclosure size and for the fact that should I end up hating the Onken I would have a fall back configuration. (Those drivers were expensive.. LOL)The driver I choose, the Iconic 165-8G was designed for horn loading and also had TS parameters that made it pretty ideal I thought for my Onken box. Driver FS is about 37Hz, but in this box in the interest of size and efficiency I tuned for right around 38Hz. There were several eminence drivers that looked interesting and would have been a lot less expensive...
Just wondering what was up with your cabinet design, your comment on the lack of extension is interesting.. I have noticed that this box design is really sensitive the amplifier damping factor, and small deviations seem to have a relatively drastic effect on the sound.
I am acquiring a measurement mic and designing and building a mic pre with phantom power. I plan to do a lot of measurements before I embark on finding the "final tuning" for my boxes.
I do know that my 3 ohm target source impedance is lower than that of the amplifier and inductor in the cross-over. I designed the amplifier and cross-over, and can fairly easily modify them to get the source impedance into the right range. Worst case I can use the 4 ohm tap on the amp, trade power for the lower source impedance..
This is how my Onkens looked like. I admit this sack shaped design is not the original intention of the Onken concept, but the parameters (85%Sd port crossectional area, 33cm port length, Onken alignment) are standard values. I simulated it in the MJK sheet with the unusual height and port/driver offset, and even here nothing indicated it shouldn`t work. Of course the sheet doesn`t take into account the direction of the port, but can this be the reason?
Attachments
hi el 'Ol I'm no expert, but I suspect that the shown configuration might result in some serious performance problems. GM or panomaniac probably could come back with some more cogent answers, in my design I deliberately attempted to stay somewhat close to the "golden ratio" although one of the ratios is more than a bit off actually.
It seems to me that such great depth relative to the height and width might result in an organ pipe like resonance. I could be all wet here.
My box is roughly 28" wide, 20" deep and 35" tall and these values worked well for me, and are not too wildly different than the original Jensen ultraflex box, although the tuning is specific to the 165-8G I am using.
My understanding is that none of the extant simulation programs model the onken properly, again someone far more expert will need to weigh in with their thoughts.
It seems to me that such great depth relative to the height and width might result in an organ pipe like resonance. I could be all wet here.
My box is roughly 28" wide, 20" deep and 35" tall and these values worked well for me, and are not too wildly different than the original Jensen ultraflex box, although the tuning is specific to the 165-8G I am using.
My understanding is that none of the extant simulation programs model the onken properly, again someone far more expert will need to weigh in with their thoughts.
Greets!
Well, if you post all the info I requested, I can 'speculate' too. Till then, I'm going to assume you screwed up somehow and/or are comparing 'apples n' oranges' since the performance 'spread' between the two is so great.
That said, no program AFAIK can model an Onken with the same degree of accuracy as a single vent BR, but performance 'trends' can be compared, which often allows us to figure out why one performs better than another.
GM
Well, if you post all the info I requested, I can 'speculate' too. Till then, I'm going to assume you screwed up somehow and/or are comparing 'apples n' oranges' since the performance 'spread' between the two is so great.
That said, no program AFAIK can model an Onken with the same degree of accuracy as a single vent BR, but performance 'trends' can be compared, which often allows us to figure out why one performs better than another.
GM
A few more or less OT comments regarding the Onken and other large speaker enclosures.
I had an interesting illustration today of why some audiophiles claim that no room should have more than one pair of speakers in it. Seems germaine at least with larger speaker systems. My old JBL's seem to have been doing a bit of a Heimholtz resonator routine in my listening room. Sold today and removed, along with them went an interesting lower mid bass resonance that I thought might be room related. The baffles were facing each other and quite close together, gap of no more than an inch or so.. Audibly different. I'm still quite surprised, although I had surmised that it would be better if they weren't in there, I was stunned to discover I could actually hear it.
Here's my very unscientific experiment to determine whether or not my lower source Z 300B PP monoblock amps would sound better than the dual mono 300B SE amp. Neither amplifier design has global NFB, both use fixed bias, and the PP amplifier is about 4 times as powerful as the other.
The PP amps have a source Z of about 2 ohms, the SE about 3. Bass was tighter and somewhat overdamped sounding with the PP amp due probably to the lower Z. Overall impression was a increased freedom from resonances, but also a substantial reduction in output level and extension. (Level comment is relative to mid/tweeter horns, and is clearly damping related.)
The PP amps however are from a long ago turning point in my developing design philosophy, and the SE amp is just better in every imaginable way - so despite the slightly underdamped bass it went right back in.
The SE amplifier slews a lot faster in the voltage domain than the PP amplifier does due to driver circuit design, (about 2X) and also has much greater power bandwidth - this is very audible.
Note I should be measuring the amplifier source impedances, and in fact this is easy to do. I will do all of this as I collect the information I need for fine tuning the system.
I think the woofers still need some break - in time prior to baseline measurements.
I will have a mic and pre-amplifier ready to go in a couple of weeks and will just have a measurement marathon when I have the time.
I will continue to post my experiences here.
I will say they are working quite well, and I am actually pretty thrilled with the result. I know they can be even better, and I am not going to rush.
Interestingly even with a total system power of just 7Wrms per channel I can achieve sustained spl levels of 106dB @ ~1m with no audible distortion, and it is extremely dynamic at these levels. This is NOT recommended for sustained listening as this is really pretty excessive, and will cause hearing damage even with relatively short exposure. The scary thing though is that there is nothing audible that would make you want to turn it down... I did it with regret...
I could probably also shake our whole 2 story house to pieces with them..
I had an interesting illustration today of why some audiophiles claim that no room should have more than one pair of speakers in it. Seems germaine at least with larger speaker systems. My old JBL's seem to have been doing a bit of a Heimholtz resonator routine in my listening room. Sold today and removed, along with them went an interesting lower mid bass resonance that I thought might be room related. The baffles were facing each other and quite close together, gap of no more than an inch or so.. Audibly different. I'm still quite surprised, although I had surmised that it would be better if they weren't in there, I was stunned to discover I could actually hear it.
Here's my very unscientific experiment to determine whether or not my lower source Z 300B PP monoblock amps would sound better than the dual mono 300B SE amp. Neither amplifier design has global NFB, both use fixed bias, and the PP amplifier is about 4 times as powerful as the other.
The PP amps have a source Z of about 2 ohms, the SE about 3. Bass was tighter and somewhat overdamped sounding with the PP amp due probably to the lower Z. Overall impression was a increased freedom from resonances, but also a substantial reduction in output level and extension. (Level comment is relative to mid/tweeter horns, and is clearly damping related.)
The PP amps however are from a long ago turning point in my developing design philosophy, and the SE amp is just better in every imaginable way - so despite the slightly underdamped bass it went right back in.
The SE amplifier slews a lot faster in the voltage domain than the PP amplifier does due to driver circuit design, (about 2X) and also has much greater power bandwidth - this is very audible.
Note I should be measuring the amplifier source impedances, and in fact this is easy to do. I will do all of this as I collect the information I need for fine tuning the system.
I think the woofers still need some break - in time prior to baseline measurements.
I will have a mic and pre-amplifier ready to go in a couple of weeks and will just have a measurement marathon when I have the time.
I will continue to post my experiences here.
I will say they are working quite well, and I am actually pretty thrilled with the result. I know they can be even better, and I am not going to rush.
Interestingly even with a total system power of just 7Wrms per channel I can achieve sustained spl levels of 106dB @ ~1m with no audible distortion, and it is extremely dynamic at these levels. This is NOT recommended for sustained listening as this is really pretty excessive, and will cause hearing damage even with relatively short exposure. The scary thing though is that there is nothing audible that would make you want to turn it down... I did it with regret...
I could probably also shake our whole 2 story house to pieces with them..
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