Here's anothere version of a similar speaker's freq resp:
http://www.artec-france.com/etudes....es&PHPSESSID=d24c908e9e81e34135a39deb3342627d
freq resp
I think you can just click on the above... note the similar response in the bass area. Although overall, with the xovers they've used, this is a fairly outstanding response curve (at least on axis, and as measured)!
here's one version with a sub added:
with sub added
and in case the links don't work, it's from this site:
http://www.artec-france.com
I have no relationship with these people, but someone mentioned them earlier, and the results are essentially similar to others...
I guess what I'm trying to say is that you need a sub to get a real full range system, and without the sub, and with the tweeter, you'll sound a bit thin subjectively, and with the sub you've got a really big speaker system!!
_-_-bear
http://www.artec-france.com/etudes....es&PHPSESSID=d24c908e9e81e34135a39deb3342627d
freq resp
I think you can just click on the above... note the similar response in the bass area. Although overall, with the xovers they've used, this is a fairly outstanding response curve (at least on axis, and as measured)!
here's one version with a sub added:
with sub added
and in case the links don't work, it's from this site:
http://www.artec-france.com
I have no relationship with these people, but someone mentioned them earlier, and the results are essentially similar to others...
I guess what I'm trying to say is that you need a sub to get a real full range system, and without the sub, and with the tweeter, you'll sound a bit thin subjectively, and with the sub you've got a really big speaker system!!
_-_-bear
The comb filter effect in the Onken is not an intentional feature, and is actually a detriment to its performance. If I understand correctly it's implicit in the large surface area of the vents, vent length and relative proximity to the driver. Apparently longer ports make it worse due to the delay? Not sure about this - I'm a newbie 
I'm currently building a pair of Onkens, and do plan to apply various acoustical treatments inside in order to control low mid range and upper mid bass reflections to the extent possible. (or hopefully necessary.)
I've tuned mine for -3dB at 38Hz which seemed like a reasonable compromise for size and efficiency. Given the types of music I listen to 40Hz performance ought to be adequate, if not I'll build some compact and relatively inefficient subwoofers later and run them with a biggish ss amplifier..
I'm currently building a pair of Onkens, and do plan to apply various acoustical treatments inside in order to control low mid range and upper mid bass reflections to the extent possible. (or hopefully necessary.)
I've tuned mine for -3dB at 38Hz which seemed like a reasonable compromise for size and efficiency. Given the types of music I listen to 40Hz performance ought to be adequate, if not I'll build some compact and relatively inefficient subwoofers later and run them with a biggish ss amplifier..
kevinkr said:The comb filter effect in the Onken is not an intentional feature, and is actually a detriment to its performance. If I understand correctly it's implicit in the large surface area of the vents, vent length and relative proximity to the driver. Apparently longer ports make it worse due to the delay? Not sure about this - I'm a newbie
I'm currently building a pair of Onkens, and do plan to apply various acoustical treatments inside in order to control low mid range and upper mid bass reflections to the extent possible. (or hopefully necessary.)
I've tuned mine for -3dB at 38Hz which seemed like a reasonable compromise for size and efficiency. Given the types of music I listen to 40Hz performance ought to be adequate, if not I'll build some compact and relatively inefficient subwoofers later and run them with a biggish ss amplifier..
Sounds reasonable to me...
But then I ask, why an Onken? If you can get the identical frequency response with a standard ported cabinet of similar volume, without the problem noted above, it seems not to have much benefit.
In addition, the large vents on the surface of the cabinet act like traps at some frequency related to their width, and no matter what present a discontinuity... where it has been shown that soft transitions, and wide baffles have the flattest frequency response, even in midrange and midbass...
...having said all that, I do run a pair of 15" Altecs in a largish ported ugly duck box that happens to have a large shelf type port at the bottom, and subs below that. But I did the large midbass cabinets only because I had a pile of them (they were originally built for Hartke as bass cabs) and I needed something very fast, quick and dirty to get from 300Hz. down to my subs @ ~60Hz... entirely non-critical for a quick and dirty fill-in driver...
_-_-bear
Onkens:for the challenge, because I have not seen nor heard a pair, because I have heard various types of horns, BR, thought they were at least ok. (Read boring, routine.) Because everything I learned in engineering school turned out not to be as concrete as it first seemed.
Because what is old is new again, what was cast off in the rush for the latest thing was often better than what replaced it.
Dogma.. I closed my mind to SE for example for at least 10yrs because people I respected told me it was a technical fossil, pointless dead end, and could not possibly offer performance acceptable by modern standards.. To my chagrin I discovered upon designing and building my first one that what I had been told was not even close to my perception of the truth.
The Onken is well regarded in Japan for its fast, lively, dynamic sound, something I am looking for, and given that most of the ideas I have since explored and adapted to my own use were originally resurrected there I thought it would be something worth trying. A lot of people here seem to like them too.. My Iconic woofers will work in traditional horn enclosures as well if I eventually decide to do something else..
Because what is old is new again, what was cast off in the rush for the latest thing was often better than what replaced it.
Dogma.. I closed my mind to SE for example for at least 10yrs because people I respected told me it was a technical fossil, pointless dead end, and could not possibly offer performance acceptable by modern standards.. To my chagrin I discovered upon designing and building my first one that what I had been told was not even close to my perception of the truth.
The Onken is well regarded in Japan for its fast, lively, dynamic sound, something I am looking for, and given that most of the ideas I have since explored and adapted to my own use were originally resurrected there I thought it would be something worth trying. A lot of people here seem to like them too.. My Iconic woofers will work in traditional horn enclosures as well if I eventually decide to do something else..
kevinkr said:
That is certainly why I like them and the A7. What they do, they do very, very well.
Do they cover the bottom octave? no. But that may be more a function of the driver than the box. But the lack of the bottom octave or octave & 1/2 just doesn't bother me because everything else is so "right." Despite the lack of energy below 50 Hz the boxes never sounded thin or small to me. Quite the contrary, they sound big and roomy. Also fleet and light of foot.
Let me go out on a limb with a musical analogy.
I play the sax (or used to). For a while I played Baritone sax and my main "talent" was volume. Yep, I could play plenty loud! Low too.
Branford Marsalis also plays sax, the tenor. With my Baritone I know I can play lower than Branford - and louder too, I bet. Does that make me a better sax player? More musical? No, not by a long shot. Let me assure you, you would much rather hear Mr. Marsalis play than hear me. No contest, even if I can play lower and louder.
It's great fun to have all that extreme bottom end, most of the old driver-cabinet combos don't. But they aren't missing much. And what they do have is glorious. That's what is important to me.
I couldn't have put it better, and hearing that the foundations of my latest foray into insanely large and expensive speaker technology might actually do what I hope for is encouraging.
The cabinets are now actually finished and are slated for delivery this Sunday, I saw one a couple of weeks ago in clamps and I was impressed. My Fiancee's Dad is a master craftsman, and has done a great job. The boxes have routed slots (rabbets) on the top and bottom panels as well as cleats on the baffle board and rear panel. They are constructed of 3/4" birch plywood, all edges are veneered, so they should be relatively attractive which isn't really necessary since they are going in my basement listening room which is off limits to most guests.
The Iconic 165-8G woofers arrived Monday morning, and are pretty close to a work of art for a speaker. They exude quality which is what I would expect for the money I guess. At 32lbs each they aren't exactly lightweights, but the very rigid basket and huge magnet indicate this is a pretty serious piece of hardware. I am looking on them as a long term investment as I more or less indicated in a previous post.
I choose the 38Hz tuning to keep box size reasonable and because even though it is possible to tune for a lower fs I wanted to maintain reasonable efficiency.
I have seemingly sorted out the issue of the uninvolving sound from the mid and tweeter horns. Swapped in my higher gain, higher power 300B which immediately made a major improvement, also 3 of the 4 diaphragms in the system were brand new and I noticed that the sound seemed to open up considerably after a couple of hours at moderately high volumes. Placement of the horn assemblies relative to the listening position also seems to play a role - still investigating what this is about.
The x-over design I worried about seems to be correct for these drivers, but I will get a mic and pre-amp in a month or so and start doing some measurements.
I plan to post pix of the system and schematic of x-over at some point.
The cabinets are now actually finished and are slated for delivery this Sunday, I saw one a couple of weeks ago in clamps and I was impressed. My Fiancee's Dad is a master craftsman, and has done a great job. The boxes have routed slots (rabbets) on the top and bottom panels as well as cleats on the baffle board and rear panel. They are constructed of 3/4" birch plywood, all edges are veneered, so they should be relatively attractive which isn't really necessary since they are going in my basement listening room which is off limits to most guests.
The Iconic 165-8G woofers arrived Monday morning, and are pretty close to a work of art for a speaker. They exude quality which is what I would expect for the money I guess.
At 32lbs each they aren't exactly lightweights, but the very rigid basket and huge magnet indicate this is a pretty serious piece of hardware. I am looking on them as a long term investment as I more or less indicated in a previous post.I choose the 38Hz tuning to keep box size reasonable and because even though it is possible to tune for a lower fs I wanted to maintain reasonable efficiency.
I have seemingly sorted out the issue of the uninvolving sound from the mid and tweeter horns. Swapped in my higher gain, higher power 300B which immediately made a major improvement, also 3 of the 4 diaphragms in the system were brand new and I noticed that the sound seemed to open up considerably after a couple of hours at moderately high volumes. Placement of the horn assemblies relative to the listening position also seems to play a role - still investigating what this is about.
The x-over design I worried about seems to be correct for these drivers, but I will get a mic and pre-amp in a month or so and start doing some measurements.
I plan to post pix of the system and schematic of x-over at some point.
Hi,
the best you can found on the french Audiophile review will be about Onken for Audax PR38 S100 (or equivalent now) wich is a very good combination.
All the mesurement of the enclosure are available, with respone curve and so on.
The size also of course !
Not only the low frequency goes in the right way but the sound is very nice.
I well know the Onken you see in the Audiophile, listeniong them for many hundred hours.
In fact, the PR38 Audax Onken is the bass at its very best...
the best you can found on the french Audiophile review will be about Onken for Audax PR38 S100 (or equivalent now) wich is a very good combination.
All the mesurement of the enclosure are available, with respone curve and so on.
The size also of course !
Not only the low frequency goes in the right way but the sound is very nice.
I well know the Onken you see in the Audiophile, listeniong them for many hundred hours.
In fact, the PR38 Audax Onken is the bass at its very best...
My Onken cabinets arrived a couple of days ago. I am now in the process of replacing some of the cleats, changing fasteners because they did not snug things down well, and gluing like crazy.
They look very nice, and I think with a little work will be pretty non-resonant for their size.
I had hoped they would be turn key, but the baffle boards were not snuggly fastened down, and the rear cleats had large gaps. (air leaks)
I figure I have about another 8 hrs of work left before the woofers can go in.
Hopefully I'll be able to post a couple of pix in the next few days.
The JBL horns I am using are basically CD type (constant directivity) if I' ve the parlance right, and don't care about orientation. Once the diffusers are installed on the mid horns, the dispersion pattern definately audibly different although I would have to look up or measure it to tell you the spread. Definitely want those diffusers though.
They look very nice, and I think with a little work will be pretty non-resonant for their size.
I had hoped they would be turn key, but the baffle boards were not snuggly fastened down, and the rear cleats had large gaps. (air leaks)
I figure I have about another 8 hrs of work left before the woofers can go in.
Hopefully I'll be able to post a couple of pix in the next few days.
The JBL horns I am using are basically CD type (constant directivity) if I' ve the parlance right, and don't care about orientation. Once the diffusers are installed on the mid horns, the dispersion pattern definately audibly different although I would have to look up or measure it to tell you the spread. Definitely want those diffusers though.
bear said:
Greets!
The physics of Helmholtz resonance and 1/2 WL pipe acoustics indicates otherwise, as does my own measurements, so we'll have to agree to disagree. Maybe these nifty port animations will help to visualize what's happening: http://www.hometheaterhifi.com/volume_5_2/cmilleressayporting.html
The way internal reflections do affect the FR by comb filtering with the driver's signal though is via modulating the diaphragm as they reflect off its backside.
True, though it can be very effective in a negative sort of way in this case since it's what's causing (impacting) the very non-flat response beginning around 300 Hz. Since typically an Onken covers a very wide BW, the vent's pipe harmonics do audibly affect the speaker's 'sound' and the longer, bigger the vents, the more they will over a wider BW before they decay away, ergo even if lowpassed below 300 Hz or whatever the vent's 2nd harmonic is, it's output will comb filter with the next driver in the chain and since it will be further away it will be even more audible. For this reason alone it's best to lowpass it as high as practical. That, or damp the vents, which of course will negate some of the reason for doing all the extra woodworking.
What happens when you double the radiation area? You get a +3 dB increase over the BW where they are both operating as point sources. Like I said in another post, with vents, you have to increase its mass for a given Fb though, so its 'Q' goes down, ergo some of the extra gain is lost, but not all. Take this to an extreme and you have a high gain 1/4 WL TL.
Agreed, you're 'preaching to the choir' with me. These alignments made sense when there was precious few tapes and no records with content below 40 Hz, but in today's wide BW world, they are totally inadequate without either a lower tuning or adding a sub system.
Again, it depends on the driver specs/alignment/amp's DF, just like any BR.
GM
kevinkr said:The comb filter effect in the Onken is not an intentional feature, and is actually a detriment to its performance. If I understand correctly it's implicit in the large surface area of the vents, vent length and relative proximity to the driver. Apparently longer ports make it worse due to the delay? Not sure about this - I'm a newbie
Greets!
Right, increasing length = increasing BW = increasing decay time = greater comb filtering with whatever driver is handling the signal. All this assumes of course that the vent's being energized at a high enough gain for this to be an audible problem and why tuning slightly below the lowest note likely to be reproduced at any appreciable amplitude is desirable, so for music other than pipe organ symphonies, the lowest note on a piano (~27.5 Hz), suffices.
GM
Hi GM,
Indeed you are right, but the reconstruction is relatively minor in the scheme of things, and at least it will be as right as I can make it.
Yes, they were expensive, second to, and only slightly less expensive than the Iconic Woofers.
I replaced most of the baffle board cleats, and some of the rear panel ones as well. They are glued and screwed, and I replaced most of the hardware with fine pitch drywall screws as they really seem to snug down well. The ones originally used left most of the cleats floating about a 1/16th of an inch off of the surface they were screwed to, no idea why..
I added some additional blocking here and there, lots of glue and roughly doubled the number of screws. All of the the new cleats are continuous with no significant gaps.
I carefully prepared the baffles and mating surfaces on the box, including repeated trial fits, the construction provides lots of surface area to bond the baffle to. I applied generous amounts (continuous beads throughout) of PL construction adhesive and installed the baffle boards. I then put about 120lbs (~55kg) of weight evenly applied to the baffles to seat them tightly in the adhesive, and let them sit overnight that way. I checked them this morning, they appear to be very tight.
I have done a lot of rapping and tapping to make sure things are relatively dead.
The rear panels fit very tightly and are held in place with about 20 screws.. There is a thin closed cell gasket on the rear cleats as well to aid in sealing.
For what I spent I would have a very good choice of both new and used High End speaker systems. Hopefully the end result will be worth it.
The homebrew JBL 4333 mids/2402H tweeter horn assemblies and x-overs now seem to be outperforming the vintage JBL C-37's they and the Onken boxes are replacing. Maybe Fostex alnico T900 or T925 horn tweeters in the fall, WTHK...
Indeed you are right, but the reconstruction is relatively minor in the scheme of things, and at least it will be as right as I can make it.
Yes, they were expensive, second to, and only slightly less expensive than the Iconic Woofers.
I replaced most of the baffle board cleats, and some of the rear panel ones as well. They are glued and screwed, and I replaced most of the hardware with fine pitch drywall screws as they really seem to snug down well. The ones originally used left most of the cleats floating about a 1/16th of an inch off of the surface they were screwed to, no idea why..
I added some additional blocking here and there, lots of glue and roughly doubled the number of screws. All of the the new cleats are continuous with no significant gaps.
I carefully prepared the baffles and mating surfaces on the box, including repeated trial fits, the construction provides lots of surface area to bond the baffle to. I applied generous amounts (continuous beads throughout) of PL construction adhesive and installed the baffle boards. I then put about 120lbs (~55kg) of weight evenly applied to the baffles to seat them tightly in the adhesive, and let them sit overnight that way. I checked them this morning, they appear to be very tight.
I have done a lot of rapping and tapping to make sure things are relatively dead.
The rear panels fit very tightly and are held in place with about 20 screws.. There is a thin closed cell gasket on the rear cleats as well to aid in sealing.
For what I spent I would have a very good choice of both new and used High End speaker systems. Hopefully the end result will be worth it.
The homebrew JBL 4333 mids/2402H tweeter horn assemblies and x-overs now seem to be outperforming the vintage JBL C-37's they and the Onken boxes are replacing. Maybe Fostex alnico T900 or T925 horn tweeters in the fall, WTHK...
I could be wrong, but I suspect that using a full range speaker in an onken type enclosure could be problematic because of the possibility of comb filtering due to driver interaction with the large port surface area.
I am not sure you could damp the internal reflections sufficiently over a broad range of frequencies to prevent problems. I have heard of people stuffing the ports in order to reduce comb filtering in some instances. Presumably this works by reducing the propagation of out of band radiation through the port.
I'm not an expert, so my concerns may or may not have merit.
GM who posts here frequently may have further thoughts on whether or not this is advisable.
I hope your comments about "soft and not punchy bass" are without basis. I will be most disappointed with the performance if that adjective applies to mine, particularly after the time, effort, and not to mention money that I have sunk into this black hole..
Mine are almost finished, I anticipate that I will be listening to them for the first time tonight. They will be crossed over at 800Hz and have a moderate amount of internal stuffing to damp unwanted internal reflections. How much of an issue if any I have with comb filtering remains to be seen.
I am not sure you could damp the internal reflections sufficiently over a broad range of frequencies to prevent problems. I have heard of people stuffing the ports in order to reduce comb filtering in some instances. Presumably this works by reducing the propagation of out of band radiation through the port.
I'm not an expert, so my concerns may or may not have merit.
GM who posts here frequently may have further thoughts on whether or not this is advisable.
I hope your comments about "soft and not punchy bass" are without basis. I will be most disappointed with the performance if that adjective applies to mine, particularly after the time, effort, and not to mention money that I have sunk into this black hole..
Mine are almost finished, I anticipate that I will be listening to them for the first time tonight. They will be crossed over at 800Hz and have a moderate amount of internal stuffing to damp unwanted internal reflections. How much of an issue if any I have with comb filtering remains to be seen.
Br give high efficiency but sometimes it occurs some boomy sound which give louder bass but not very well hold : the bass seem to go more no time than the music.
With Onken, yhe large port area may create a hole ar frequency but the sound is lighter, much more pleasant in my mind.
I would try it, but sure the box will be finished only if the listening result is on my request.
My first goal is to avoid boomiy sound --> so I will accept a loss of level in the bass and be sure that the low cut will be upper than the Fs because of the Xmax.
With Onken, yhe large port area may create a hole ar frequency but the sound is lighter, much more pleasant in my mind.
I would try it, but sure the box will be finished only if the listening result is on my request.
My first goal is to avoid boomiy sound --> so I will accept a loss of level in the bass and be sure that the low cut will be upper than the Fs because of the Xmax.
I finished my Onken boxes last night and spent about 2 1/2 hours of captivated listening. I now understand what the hype is all about.
It's almost as if the box wasn't there. There is no boom, there is bass, very deep, tight and well controlled. Quick. There is no port noise. In my pair there is no evidence of comb filtering either. To say that they seem well behaved is an understatement.
I applied a single layer of acoustic padding to the back panel, one of the internal vent partitions, and a double layer on the bottom.
I spent a great deal of time making sure that the boxes were solidly held together. Everything is screwed and glued. At my usual moderate listening levels I can't feel any vibration at all in the box.
I designed the box, choose the driver for the relatively high source impedances of the amplifiers I use. This seems to work FINE!
The Iconic Woofer is pretty amazing, and I am now glad I dug deep into my wallet for a pair.
All in all initial impression of my new system is that it is a big improvement in a lot of ways over what it replaced, and that wasn't too shabby either.
The bottom end is what I had hoped for, the rest of it (mid/high horns) seems to be reasonably close and is quite tweakable as I learn how to tune it.
No regrets.
It's almost as if the box wasn't there. There is no boom, there is bass, very deep, tight and well controlled. Quick. There is no port noise. In my pair there is no evidence of comb filtering either. To say that they seem well behaved is an understatement.
I applied a single layer of acoustic padding to the back panel, one of the internal vent partitions, and a double layer on the bottom.
I spent a great deal of time making sure that the boxes were solidly held together. Everything is screwed and glued. At my usual moderate listening levels I can't feel any vibration at all in the box.
I designed the box, choose the driver for the relatively high source impedances of the amplifiers I use. This seems to work FINE!
The Iconic Woofer is pretty amazing, and I am now glad I dug deep into my wallet for a pair.
All in all initial impression of my new system is that it is a big improvement in a lot of ways over what it replaced, and that wasn't too shabby either.
The bottom end is what I had hoped for, the rest of it (mid/high horns) seems to be reasonably close and is quite tweakable as I learn how to tune it.
No regrets.
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