Hi all, I really have had no high frequency problems whatsoever,thanks to the Beyma tweeter, which really is totally unnoticeable in the set up and appears to sound sweet and smooth all the way up the frequency range. Also, in my set up, the two 12" woofers were clearly more tonally full in sound with more solid imaging and transparency than with one, by quite a considerable margin. My perceived problems are more at the lower end.
I am glad others have found the sound so live and hence addictive. Please note, in my set up, valve amps have a tremendous effect in the perceived energy, tonal colours, dynamics and 3d soundstaging than any solid state I have used so far. I have had audio note oto el84 (very highly modified) work wonders on them but with reasonably good results with the Pass F5 and other pure class A power amps.
I am glad others have found the sound so live and hence addictive. Please note, in my set up, valve amps have a tremendous effect in the perceived energy, tonal colours, dynamics and 3d soundstaging than any solid state I have used so far. I have had audio note oto el84 (very highly modified) work wonders on them but with reasonably good results with the Pass F5 and other pure class A power amps.
It must be the Beyma as I had to pad the high down with the B&C DE10 driver. Anyhow, I currently run just one woofer with a 4.4uf cap and hook up a 10MH coil in series to the other woofer which give a crisper/bolder sound at the lower mid. I've found a match in heaven for my 2 watt 45 tube amp after so many years of looking for that special speakers. Thanks audiojoy for your post, you've helped my system sound so much better.
Audiojoy thanks for sharing your experiences.
I have owned the Bastanis Prometheus for more than three years now which you have copied and your description of the sound you are hearing mirrors mine. I have the single full ranger (not the dual like on yours and the Atlas) and have been thinking about adding a second driver but don't feel like forking over $800 right now for it.
The only problem I also notice is that lack of warmth, tonality and hollowness you describe. I have not played around with other drivers so I too wonder if it is a function of the driver or if this is just inherent with open baffles which lack the box to load the driver differently.
I have owned the Bastanis Prometheus for more than three years now which you have copied and your description of the sound you are hearing mirrors mine. I have the single full ranger (not the dual like on yours and the Atlas) and have been thinking about adding a second driver but don't feel like forking over $800 right now for it.
The only problem I also notice is that lack of warmth, tonality and hollowness you describe. I have not played around with other drivers so I too wonder if it is a function of the driver or if this is just inherent with open baffles which lack the box to load the driver differently.
SetOrbust,
The lack of timbral accuracy has been plaguing me for a while now, as well as the inability to get sub 100hz sound with the power and depth obtained from an enclosed sub. Nonetheless, it is still the most live sounding and addictive speaker i have ever owned.
You will have read above the suggestion made by some one else that the inherent timbral qualitites are as a result of resonances from enclosures. In agreement with this conclusion would be the fact that a lot of instruments and even our own human voices emanate from enclosed areas, which by definition are themselves bound by walls, which also resonate and hence contribute to the overall tone.
I did add a boxed wooden enclosure to the base of my open baffle cabinet and had a port at the top so that I could get resonance from some of the output of the mid woofers lying above it in that box. Unfortunately I ended up with even more abberrant results, see picture on
http://www.diyaudio.com/forums/full-range/158553-new-open-baffle-concept-6.html
and my audible findings are on the next page.
Doubling up the woofers trust me makes a whole lot of difference in terms of solidity of imaging and a more fullsome tone, i could never go back to my original single driver, but the more subtle complex harmonics are not there. You can also improve the tonal range by changing the crossover cap for the tweeter by one or two units up or down as a fine tune, that helps a little.
I am waiting to try my el84 valve amp on the speakers shortly to see if it is not a result of solid state amplification. Also I hear that hemp based cones have very good tonal qualities so it looks like i will be getting those rather expensive Tone Tubbys 12" hemp cone........... not sure if I should go with the alnico or not. Other than that further experimentation on the baffle material to make it more resonant might be the way to go, the obvious choice would be to use mdf. Or enclosing each speaker driver in its own own small open back box??? so may theories, so little experience in speaker building physics to be able to theoretically discount these ideas or not without trying them first.
Coming back to the sub problem. Using enclosed ported subs have always sounded slow and disconnected from the main system unlike my open back dipole bass system. But the latter even with 12" xtra long throw peerless woofers are feeble compared to a well integrated subwoofer speaker system.
The lack of timbral accuracy has been plaguing me for a while now, as well as the inability to get sub 100hz sound with the power and depth obtained from an enclosed sub. Nonetheless, it is still the most live sounding and addictive speaker i have ever owned.
You will have read above the suggestion made by some one else that the inherent timbral qualitites are as a result of resonances from enclosures. In agreement with this conclusion would be the fact that a lot of instruments and even our own human voices emanate from enclosed areas, which by definition are themselves bound by walls, which also resonate and hence contribute to the overall tone.
I did add a boxed wooden enclosure to the base of my open baffle cabinet and had a port at the top so that I could get resonance from some of the output of the mid woofers lying above it in that box. Unfortunately I ended up with even more abberrant results, see picture on
http://www.diyaudio.com/forums/full-range/158553-new-open-baffle-concept-6.html
and my audible findings are on the next page.
Doubling up the woofers trust me makes a whole lot of difference in terms of solidity of imaging and a more fullsome tone, i could never go back to my original single driver, but the more subtle complex harmonics are not there. You can also improve the tonal range by changing the crossover cap for the tweeter by one or two units up or down as a fine tune, that helps a little.
I am waiting to try my el84 valve amp on the speakers shortly to see if it is not a result of solid state amplification. Also I hear that hemp based cones have very good tonal qualities so it looks like i will be getting those rather expensive Tone Tubbys 12" hemp cone........... not sure if I should go with the alnico or not. Other than that further experimentation on the baffle material to make it more resonant might be the way to go, the obvious choice would be to use mdf. Or enclosing each speaker driver in its own own small open back box??? so may theories, so little experience in speaker building physics to be able to theoretically discount these ideas or not without trying them first.
Coming back to the sub problem. Using enclosed ported subs have always sounded slow and disconnected from the main system unlike my open back dipole bass system. But the latter even with 12" xtra long throw peerless woofers are feeble compared to a well integrated subwoofer speaker system.
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That is too bad your rear quasi box did not pan out.
I should add that adding felt to the inside of the baskets helped me somewhat in the smoothness department.
I have the sealed Bastanis woofers that cover from the 30's to up to 110hz. Works pretty good. I also have the 18 inch eminence woofers to try in Roberts new w type open baffle that I will build next month to compare. I use a couple of subs for below 30hz that add a solid foundation to the music but maybe are a tad slow.
From everything I have read about the Tone tubby it is not a drop in full range speaker and have no desire to use it myself.
If I don't add a second driver to my own speaker I am thinking of building another OB speaker with four 6-8 inch drivers spaced closely in a circle, adding a tweeter and woofer like the Prometheus. The key is to find something as detailed and dynamic as the eminence but maybe a little more warm in the lower mids.
I should add that adding felt to the inside of the baskets helped me somewhat in the smoothness department.
I have the sealed Bastanis woofers that cover from the 30's to up to 110hz. Works pretty good. I also have the 18 inch eminence woofers to try in Roberts new w type open baffle that I will build next month to compare. I use a couple of subs for below 30hz that add a solid foundation to the music but maybe are a tad slow.
From everything I have read about the Tone tubby it is not a drop in full range speaker and have no desire to use it myself.
If I don't add a second driver to my own speaker I am thinking of building another OB speaker with four 6-8 inch drivers spaced closely in a circle, adding a tweeter and woofer like the Prometheus. The key is to find something as detailed and dynamic as the eminence but maybe a little more warm in the lower mids.
The Tone tubby's show a good flattish frequency response from about 200 to 4-5k which is what I suspect my present eminence are pumping out. The hemp cone is where the magic apparently lies. Adding tonal warmth and timbre. If you go onto the professional audio forums, these speakers are absolutely adored for their midrange and not just for guitars either. Theey are also promoted for use in open back cabinets, so cone movement must be adequate. Too bad not too many 'audiophiles' have given them ago, i suspect the price is a little prohibitive, certainly for the alnico. The ceramics are very cheap though, and the 'BOMB' combination of ceramic plus alnico appears very popular. But cannot be sure if it will work wonders for our application.
Nullspace has written quite a lot on his own Tone tubby OB's. He suggests serious eq.
Tone Tubby alnico hemp drivers
Sometimes one has to be careful what they wish for. I had a 10 inch and 15 inch Tannoy Golds in my basement recently. They are known for their warmth and beautiful sound with vocals. Unfortunately they both sounded so non-detailed and just took away too much in comparison to my Prometheus. I thought about many vintage drivers but there seems to be a common comment by users that they lack detail.
So right now I am hoping to find something that falls in the middle.
Tone Tubby alnico hemp drivers
Sometimes one has to be careful what they wish for. I had a 10 inch and 15 inch Tannoy Golds in my basement recently. They are known for their warmth and beautiful sound with vocals. Unfortunately they both sounded so non-detailed and just took away too much in comparison to my Prometheus. I thought about many vintage drivers but there seems to be a common comment by users that they lack detail.
So right now I am hoping to find something that falls in the middle.
Thanks setorbust for the warning.
Nullspace did not use the two drivers full range but segmented the two drivers further to augment various frequencies with rather complex looking crossovers. So his design concept is going a long a different route. There is a colleague on our very own diyaudio, from Germany, forget his name, who built a Bastanis copy also, but using a single woofer per speaker using the Tone Tubby alnico. What was he using before the Tone Tubby? an Eminence 12"
Nullspace did not use the two drivers full range but segmented the two drivers further to augment various frequencies with rather complex looking crossovers. So his design concept is going a long a different route. There is a colleague on our very own diyaudio, from Germany, forget his name, who built a Bastanis copy also, but using a single woofer per speaker using the Tone Tubby alnico. What was he using before the Tone Tubby? an Eminence 12"
Done some more experimenting. Rather rare in my experience to see 12" drivers have their dust caps cut out and replaced with a plug.
Well I literally pulled off the dust caps from the Eminence 12" drivers, with great ease and no apparent damage. I played them like this and they had subjectively lost a lot of the midrange,e.g voices sounded very thin and bright. So I lowered the tweeter freqency crossover to 4uf and the midrange returned once more but still clearly had tonal abberrations, the worst of which was sibilance in the treble, which seem worse than before the surgery. Time for these phase plug things.... Added rdc cones into the holes and this absorbed so much of the enegy that it sounded dull and lacked dynamics. Replaced these with aluminium cones and boy did I get a surprise. In very simple subjective terms, I had my original sound back before the dust caps were removed but with the treble edginess and sibilance gone, much more obvious smoothness to the mid range , giving voices a more realistic feel to them and thereby improving their presence factor. The cymbals now sounded so much more sweeter and more solid sounding then the shrill lighter sound before. The lower midrange also had the feeling of being fleshed out which added to the overall more natural warmth to instruments and voices. I will never be able to do an A/B comparison for obvious reasons but every track I listen to just seems so much more real, relaxed and natural sounding now.
Some of you will think that changing the tweeter crossover might be the major factor, well let me tell you i have played with the crossover time and again, up and down like a YoYo before these latest round of mods, and the treble sibilance, lack of midrange and lower midrange warmth was never achievable in the way it is now.
There is no doubt the woofer dust caps were contributing to the midrange sound I was initially enjoying before being sacrificed.
Well I literally pulled off the dust caps from the Eminence 12" drivers, with great ease and no apparent damage. I played them like this and they had subjectively lost a lot of the midrange,e.g voices sounded very thin and bright. So I lowered the tweeter freqency crossover to 4uf and the midrange returned once more but still clearly had tonal abberrations, the worst of which was sibilance in the treble, which seem worse than before the surgery. Time for these phase plug things.... Added rdc cones into the holes and this absorbed so much of the enegy that it sounded dull and lacked dynamics. Replaced these with aluminium cones and boy did I get a surprise. In very simple subjective terms, I had my original sound back before the dust caps were removed but with the treble edginess and sibilance gone, much more obvious smoothness to the mid range , giving voices a more realistic feel to them and thereby improving their presence factor. The cymbals now sounded so much more sweeter and more solid sounding then the shrill lighter sound before. The lower midrange also had the feeling of being fleshed out which added to the overall more natural warmth to instruments and voices. I will never be able to do an A/B comparison for obvious reasons but every track I listen to just seems so much more real, relaxed and natural sounding now.
Some of you will think that changing the tweeter crossover might be the major factor, well let me tell you i have played with the crossover time and again, up and down like a YoYo before these latest round of mods, and the treble sibilance, lack of midrange and lower midrange warmth was never achievable in the way it is now.
There is no doubt the woofer dust caps were contributing to the midrange sound I was initially enjoying before being sacrificed.
I'm encouraged by this experimentation and satisfaction with pro-audio drivers and 'vintage' technology. I look around at contemporary 'hi-fi' and I see an industry that has moved backward to some degree with regard to fidelity. I'm thankful that people here and in other places have steered me to 'the good stuff' at my ripe middle age of 34.
I have built large OB speakers with fullrange drivers and 15" pro audio drivers. Nothing ever moves more than 1mm and the sound is just...
I have built large OB speakers with fullrange drivers and 15" pro audio drivers. Nothing ever moves more than 1mm and the sound is just...
Hmm, I'd have thought small sealed woofers will sound slower (and much more distorted)! And I would put that down to their lower efficiency and longer travel necessitated by being smaller.
There are other compromises for getting more bass like the "H frame" but I don't know if that's what you're after.
Thorsten Loesch told me (wrt to my thread on a 3 way OB) to try one woofer sealed and one open baffle. His comment was directed at smaller room systems but it's worth a thought. I've often wondered about a best of all worlds approach like that. For me I don't have the space but....
Simon
There are other compromises for getting more bass like the "H frame" but I don't know if that's what you're after.
Thorsten Loesch told me (wrt to my thread on a 3 way OB) to try one woofer sealed and one open baffle. His comment was directed at smaller room systems but it's worth a thought. I've often wondered about a best of all worlds approach like that. For me I don't have the space but....
Simon
HI Simon good to hear from you again, badly need to go back through how you made that microphone set up very keen to get some measurements.
Sounds good, one sealed,one open, perhaps on the same push pull frame with wiring kept as it is and just seal one of the units.
About to put a metallic phase plug on the tweeters.......... can I do that with compression drivers???
Will summarise what I have done so far with pictures this weekend. Dont forget the air base support experiment, truely helpful on these open baffles.
Sounds good, one sealed,one open, perhaps on the same push pull frame with wiring kept as it is and just seal one of the units.
About to put a metallic phase plug on the tweeters.......... can I do that with compression drivers???
Will summarise what I have done so far with pictures this weekend. Dont forget the air base support experiment, truely helpful on these open baffles.
Hi Audiojoy
The sealed woofers are not sub-woofers, they are equivalent to what bass players use (bass players don't use sub-woofers).
I have always preferred 2 x 10" (for prat) over single 15" with my bass playing, so maybe you might prefer that setup over a single 15".
The eminence delta is quite good, have alook at them.
Seriously though, before you spend big money on the tone tubbys, please spend the money on the woofers to make the sealed bass cabinets.
I think you will get a lot more than you expect.
I have made headway with that midrange tonal colour/timbre/warmth thing.
Messed around a bit more with those round tabs. After much experimentation i discovered that a lot of that shouting and midrange tonal thinness was due to the woofer paper cones and had nothing to do with the tweeter. By adding specific sizes and specific numbers in specific sites i was able to dial in a much improved tonal quality to the midrange and much needed warmth, the hollowness is now pretty much gone, there is hardly any treble uplift and the shouting thank god is no longer noticeable.
Let me stress you need to add ONLY TWO of the 4cm size tabs (other sizes have less favourable effects), and they only work best placed at the mid point of the radius of the cones at opposing ends. I would say the changes are dramatic in subjective audible terms, possibly one of the most dramatic of all the tweaks I have made.
Messed around a bit more with those round tabs. After much experimentation i discovered that a lot of that shouting and midrange tonal thinness was due to the woofer paper cones and had nothing to do with the tweeter. By adding specific sizes and specific numbers in specific sites i was able to dial in a much improved tonal quality to the midrange and much needed warmth, the hollowness is now pretty much gone, there is hardly any treble uplift and the shouting thank god is no longer noticeable.
Let me stress you need to add ONLY TWO of the 4cm size tabs (other sizes have less favourable effects), and they only work best placed at the mid point of the radius of the cones at opposing ends. I would say the changes are dramatic in subjective audible terms, possibly one of the most dramatic of all the tweaks I have made.
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