I hopew you guys publish a comparative report on your listening findings on these amplifiers.
Good luck with your meet.
Good luck with your meet.
Is something on at Andrew's? Why wasn't I invited? Is this the cryptic reference to "might see you on the W/E" in a recent email?terry j said:
I am very interested, and will attend if I possibly can.HiFiNutNut said:
If you could see the stack of Pro poweramps here for the HT, you would change your mind on my opinions re SS.
I wish it was further away.Bratislav said:
I would just like to add some comments about the modifications Bill has made.
First, with regard to the active circuits, as far as I know Bill has matched the transfer functions of my design to with in a fraction of a dB. We communicated on this and, due to Bill's unique installation I do not believe the omitted active stages would have any adverse effect on the system in his application. Whether it is an improvement or not would be impossible to tell without having the original active crossover available for comparison. As designed, I kept the number of active stages in line with the midrange/tweeter panel at a minimum while allowing flexibility to be used with a variety of pre and power amplifiers.
Second, with regard to the passive crossover mods I have examined Bill's topology. The system response remains very close to the response using the passive crossover of my design.
Bill chose to eliminate the RLC trap in series with the midrange since he believed the cap would further veil the midrange. I don't particularly agree as the major conduction path in the midrange pass band is through the inductor, L2. The trap is used to address a resonance in the stop band which I believe is of greater significance. Of course, with the fully active version this becomes a moot point. In any event, with the hybrid design using the passive mid/twe crossover, the builder has the option to make such simple changes to the passive crossover to suite his ear/environment. I do not object to such “tweaking”.
First, with regard to the active circuits, as far as I know Bill has matched the transfer functions of my design to with in a fraction of a dB. We communicated on this and, due to Bill's unique installation I do not believe the omitted active stages would have any adverse effect on the system in his application. Whether it is an improvement or not would be impossible to tell without having the original active crossover available for comparison. As designed, I kept the number of active stages in line with the midrange/tweeter panel at a minimum while allowing flexibility to be used with a variety of pre and power amplifiers.
Second, with regard to the passive crossover mods I have examined Bill's topology. The system response remains very close to the response using the passive crossover of my design.
An externally hosted image should be here but it was not working when we last tested it.
Bill chose to eliminate the RLC trap in series with the midrange since he believed the cap would further veil the midrange. I don't particularly agree as the major conduction path in the midrange pass band is through the inductor, L2. The trap is used to address a resonance in the stop band which I believe is of greater significance. Of course, with the fully active version this becomes a moot point. In any event, with the hybrid design using the passive mid/twe crossover, the builder has the option to make such simple changes to the passive crossover to suite his ear/environment. I do not object to such “tweaking”.
John,
Thanks for the insights of your crossovers. I agree with your comments. By the way, the passive XO I sent you a few weeks ago is now out of date. The component values are now quite different.
Builders and John,
For the active XO for the woofer, I would like the HP filter to be at the last stage so that the capacitors can help eliminate any DC offset. This must take the power amplifier impedance into consideration. This would suit my system only and perhaps not others. This is an example for how I reduced the number of opamps from 10 to 7. The changes do not affect the transfer function, as modelled from LTSpice.
Although I have my own passive XO, it does not suggest that John K' passive XO sounds bad. Not at all. John's passive XO sounds very good and very accurate.
I have one of the latest versions of the XO that is almost ruler flat which was derived from John's measurement graphs and simulations he sent me as well as my own measurements and simulations. Let me call it XO-1. I believe this may be the flattest of all the versions I have tried. Seriously, I could not tell errors from the sound it produces. Although I have not heard John K's passive XO for a while, I believe they sound identical or very close, from my memory it was so, and I can see from the simulations of system response that they are within a fraction of a dB difference.
With XO-1, and only with a very flat response, sopranos, tenors and baritons sound real, as you would hear from live opera singings. No other versions of the XO could produce this effect. I believe musicians would like this version the best.
However, I found the sound slightly hard and cold on less well recorded music, depending on how the music was recorded. I found a mild BBC dip (see Linkwitz' Pheonix note) does remove the problem. Also a slightly reduced treble would reduce further harshness from bad recordings.
Therefore I derived another version of the XO. Let me call it XO-2. Some of my audiophile friends love this version. They told me: "Bill, this is some very high-end, audiophile golden sound that is unique to your speakers. It is different from any other speakers. Money can not buy this sound. It is unique. You should be very proud of it." Some also said that they could not identify any fault with the sound.
In comparison, if I listen to individual voices and musical instruments, the XO-1 sounds more accurate. For XO-2 it is slightly less so, but overall, it sounds more "musical" and pleasant to the ears. It does not have any coldness instead having some warmth. I confess it is slightly coloured, but perhaps coloured in a nice way.
Interestingly, XO-1 and XO-2 does not deviate more than 1dB thorought the audio spectrum, yet they sound so different! I have been tweeking various versions of my XOs at a fraction of a dB within an octave and two and tried to identify the differences in sound.
So I believe that in choosing between John K's passive XO or mine it is not a matter of which one is better or worse, it is more of a personal taste. I was struggling with which XO to choose for the show tomorrow. However, I have decided to spend today to derive a XO-3 in between XO-1 and XO2.
For the passive XO, I now cross it at about 1.8kHz. This may give better polar response. Although I have not used the LCR to damp the stop band resonances of the woofer, the response at 3.5kHz from a steeper XO at 1.8kHz would be the same or lower than when the LCR is used.
Regards,
Bill
Thanks for the insights of your crossovers. I agree with your comments. By the way, the passive XO I sent you a few weeks ago is now out of date. The component values are now quite different.
Builders and John,
For the active XO for the woofer, I would like the HP filter to be at the last stage so that the capacitors can help eliminate any DC offset. This must take the power amplifier impedance into consideration. This would suit my system only and perhaps not others. This is an example for how I reduced the number of opamps from 10 to 7. The changes do not affect the transfer function, as modelled from LTSpice.
Although I have my own passive XO, it does not suggest that John K' passive XO sounds bad. Not at all. John's passive XO sounds very good and very accurate.
I have one of the latest versions of the XO that is almost ruler flat which was derived from John's measurement graphs and simulations he sent me as well as my own measurements and simulations. Let me call it XO-1. I believe this may be the flattest of all the versions I have tried. Seriously, I could not tell errors from the sound it produces. Although I have not heard John K's passive XO for a while, I believe they sound identical or very close, from my memory it was so, and I can see from the simulations of system response that they are within a fraction of a dB difference.
With XO-1, and only with a very flat response, sopranos, tenors and baritons sound real, as you would hear from live opera singings. No other versions of the XO could produce this effect. I believe musicians would like this version the best.
However, I found the sound slightly hard and cold on less well recorded music, depending on how the music was recorded. I found a mild BBC dip (see Linkwitz' Pheonix note) does remove the problem. Also a slightly reduced treble would reduce further harshness from bad recordings.
Therefore I derived another version of the XO. Let me call it XO-2. Some of my audiophile friends love this version. They told me: "Bill, this is some very high-end, audiophile golden sound that is unique to your speakers. It is different from any other speakers. Money can not buy this sound. It is unique. You should be very proud of it." Some also said that they could not identify any fault with the sound.
In comparison, if I listen to individual voices and musical instruments, the XO-1 sounds more accurate. For XO-2 it is slightly less so, but overall, it sounds more "musical" and pleasant to the ears. It does not have any coldness instead having some warmth. I confess it is slightly coloured, but perhaps coloured in a nice way.
Interestingly, XO-1 and XO-2 does not deviate more than 1dB thorought the audio spectrum, yet they sound so different! I have been tweeking various versions of my XOs at a fraction of a dB within an octave and two and tried to identify the differences in sound.
So I believe that in choosing between John K's passive XO or mine it is not a matter of which one is better or worse, it is more of a personal taste. I was struggling with which XO to choose for the show tomorrow. However, I have decided to spend today to derive a XO-3 in between XO-1 and XO2.
For the passive XO, I now cross it at about 1.8kHz. This may give better polar response. Although I have not used the LCR to damp the stop band resonances of the woofer, the response at 3.5kHz from a steeper XO at 1.8kHz would be the same or lower than when the LCR is used.
Regards,
Bill
John,
May I have your advice here?
I have never played the NaO in a large room. The demo room will be quite large. I am thinking about placing the speakers about 2.8 metres from the wall behind it. What do you think?
Regards,
Bill
May I have your advice here?
I have never played the NaO in a large room. The demo room will be quite large. I am thinking about placing the speakers about 2.8 metres from the wall behind it. What do you think?
Regards,
Bill
Hi Bill,
It's hard to predict how it will sound. You may lose a little SPL, but it may be an advantage in other ways.
Having played my NaO 2T in 2 completely different room, I woud suspect that with big rooms, and ~10ft behind the speaker you will have a higher ratio of direct to reflected sound, so listeners may experience a little higher clarity and detail.
Compared to other DIY speakers (SEAS Thor, ProAc 2.95 clone, Zaph Audio All Metal 2-way) the NaO2T sounds categorically better in *any* room and any placement that I've tried.
Obviously no-one told John K that dipoles were fussy with room placement. 😉
Joking aside, I suspect that the flexibility in the hybrid crossover has a lot to do with this. I am aware you don't have the rear tweeter on/off or U-frame/sealed switch selection, but do you have ultra-low bass, bass and treble adjustments built into your crossovers, like the NaO 2T?
This has been very useful for room tuning IME, and something worth trying when you set up prior to the show. Perhaps run some tests tones, and listen to half a dozen tracks just to hear for yourself.
It's hard to predict how it will sound. You may lose a little SPL, but it may be an advantage in other ways.
Having played my NaO 2T in 2 completely different room, I woud suspect that with big rooms, and ~10ft behind the speaker you will have a higher ratio of direct to reflected sound, so listeners may experience a little higher clarity and detail.
Compared to other DIY speakers (SEAS Thor, ProAc 2.95 clone, Zaph Audio All Metal 2-way) the NaO2T sounds categorically better in *any* room and any placement that I've tried.
Obviously no-one told John K that dipoles were fussy with room placement. 😉
Joking aside, I suspect that the flexibility in the hybrid crossover has a lot to do with this. I am aware you don't have the rear tweeter on/off or U-frame/sealed switch selection, but do you have ultra-low bass, bass and treble adjustments built into your crossovers, like the NaO 2T?
This has been very useful for room tuning IME, and something worth trying when you set up prior to the show. Perhaps run some tests tones, and listen to half a dozen tracks just to hear for yourself.
Hi, just working on my XO-3 and it appears to be working well.
I am very happy with the sound right now, without a hint of harshness or coldness on some recordings with XO-1 and the artificial warmth injected in the XO-2.
Further listening is required, however, I suspect I am running out of time, and need to re-solder the XO for tomorrow's show.
I am very happy with the sound right now, without a hint of harshness or coldness on some recordings with XO-1 and the artificial warmth injected in the XO-2.
Further listening is required, however, I suspect I am running out of time, and need to re-solder the XO for tomorrow's show.
HiFiNutNut said:
Two things here. First, due to the relatively high gain of the dipole eq I do not recommend removing the input cap (DC blocking cap) because if the is any DC offset in the input it will be amplified which could potentially affect the performance of later stages. Second, if it is desired to have an additional DC block at the LP output of the active crossover it is a simple matter to install the appropriate sized cap (based on woofer amplifier input impedance) between the PC board LP out and the LP output jack.
With regards to the passive crossover, I two must confess to liking to tweak. However, over the last two years I have not found a particular mod that I fell yields a sufficient, overall improvement that is suitable for release. I want the system design to remain as stable as possible. That said, I do have some passive modifications which I am considering releasing but I am continuing to evaluate these changes. In truth they are rather minor.
As you can see, Bill prefers to tinker and I have no problem with that. But it is an approach I can not take since I can not constantly revise the system.
HiFiNutNut said:
I am concerned that 2.8 M might be getting a little far from the wall. The delay in the reflected sound would approach 17 msec and could result in a loss of detail or directional cues. I imagine that it would be quickly evident. My own preference is about 1.5 to 2 M.
hi John and Bill,
I just got home from listening to the NaO, what a wonderful experience. These are fantastic speakers. 😀
Thanks Bill for taking the time to set up this demonstration. The rest of your system is excellent and really allow the NaO shine. Your choice of music was great, it really showed off the capablilities of your system.
The down side is, I now realise how average my speakers are.
regards
I just got home from listening to the NaO, what a wonderful experience. These are fantastic speakers. 😀
Thanks Bill for taking the time to set up this demonstration. The rest of your system is excellent and really allow the NaO shine. Your choice of music was great, it really showed off the capablilities of your system.
The down side is, I now realise how average my speakers are.
regards
Thanks for the positive feedback Greg. I'm glad you enjoyed the listen experience. And thanks to Bill (1/2 a world away) for the hosting the get together.
Thanks for your kind words, Greg.
I think it went well. People were enjoying the music and the audio equipments. I received "congradulations for having such a nice system" from many hard-core audiophiles. I was quite happy not because I received good comments, but because I could do something and share something with people and make them happy.
However, the overly reverberant room was very difficult. I found the details and attacks of the music were lost. We had two rooms to choose. The small room (still quite large at 7.5m x 12m) was very reverberant with no carpet and really nothing to damp the sound, while the carpeted big room (twice the size of the small room?) was too dampped. I did not think the speakers have the SPL to use the big room so I chose the smaller room. Nevertheless, a club mate told me that this was the best sound he heard in the small room comparing to all previous demos using the small room.
Greg, as said, feel free to bring your DIY amplifier(s) to my place to compare to my Optimos amps, and listen to the NaO again. They sound much, much better in my room than yesterday's demo room. When we finished the session yesterday, a few guys came over to my place to continue listening to the speakers at my place. They all said it was a night and day difference, even though the experience in the show was not bad.
Regards,
Bill
I think it went well. People were enjoying the music and the audio equipments. I received "congradulations for having such a nice system" from many hard-core audiophiles. I was quite happy not because I received good comments, but because I could do something and share something with people and make them happy.
However, the overly reverberant room was very difficult. I found the details and attacks of the music were lost. We had two rooms to choose. The small room (still quite large at 7.5m x 12m) was very reverberant with no carpet and really nothing to damp the sound, while the carpeted big room (twice the size of the small room?) was too dampped. I did not think the speakers have the SPL to use the big room so I chose the smaller room. Nevertheless, a club mate told me that this was the best sound he heard in the small room comparing to all previous demos using the small room.
Greg, as said, feel free to bring your DIY amplifier(s) to my place to compare to my Optimos amps, and listen to the NaO again. They sound much, much better in my room than yesterday's demo room. When we finished the session yesterday, a few guys came over to my place to continue listening to the speakers at my place. They all said it was a night and day difference, even though the experience in the show was not bad.
Regards,
Bill
John,
It was a pleasure.
I think it is a pity that not many people have a chance to listen to the NaO speakers while in the HiFi industry there are too many hypes.
Thanks for your generous give-aways of your substantial knowledge and experience of OB speakers to the DIY world and I am sure a lot of people (including myself) have learnt a great deal from you.
Regards,
Bill
It was a pleasure.
I think it is a pity that not many people have a chance to listen to the NaO speakers while in the HiFi industry there are too many hypes.
Thanks for your generous give-aways of your substantial knowledge and experience of OB speakers to the DIY world and I am sure a lot of people (including myself) have learnt a great deal from you.
Regards,
Bill
Andy G, Terri, Brett,
Hi, guys. I did not see you yesterday. How did it turn out at North Richmond? I am always interested in any exotic stuff.
Regards,
Bill
Hi, guys. I did not see you yesterday. How did it turn out at North Richmond? I am always interested in any exotic stuff.
Regards,
Bill
Hi Bill, sorry I couldn't make it. Didn't get to Richmond either, but I still hope I get to hear them one day.HiFiNutNut said:
My freind Henry and I would like to thank the audio club and Bill for allowing us to listen to the speakers and amps.
Despite the room the sound was wonderful.
Regards
Harry
Despite the room the sound was wonderful.
Regards
Harry
HiFiNutNut said:
very sorry Bill.
Yes Brett, there was something on at andrews.
However, as the gods must have decided at their whim, the intended happenings at northo did not happen. For a start one of the 'main attractions' blew a fuse and so were unable to be heard by those who had not heard them before.
Luckily, we DID have andy g bring out a few of his speakers for a 'show and tell' so we did have music after all!
so basically the day was spent as a bit of a bbq and chinwag really.
It was very much a pity that some of the few 'cross forum' gtg's happened to clash. these things (which I urge all to participate in) happen so rarely that to have two of them clash is a real bugger.
I really do understand about the large room, having experienced it myself once. The fact that even under those trying circumstances they shined is a testament to all.
One day Bill, one day!!!
- Status
- Not open for further replies.