For battle with resonances and not only, I will recommend two excellent online resources:
https://www.wavtones.com/functiongenerator.php
https://www.audiocheck.net/index.php
Genius behind them is Dr. Ir. Stéphane Pigeon 🙂
Anyway, I'm really impressed with your project, ideas and experiments!
Not so ordinary, but brave and smart.
Reading on daily basis 🙂 Wish you success!
https://www.wavtones.com/functiongenerator.php
https://www.audiocheck.net/index.php
Genius behind them is Dr. Ir. Stéphane Pigeon 🙂
Anyway, I'm really impressed with your project, ideas and experiments!
Not so ordinary, but brave and smart.
Reading on daily basis 🙂 Wish you success!
Hi,
as promised - and forgot 😀 - here the XO of the last version:
as promised - and forgot 😀 - here the XO of the last version:
With all due respect I find this XO really strange.
Is this a 2way or 2.5way or what?
I would personally run Alpha 15 with a 1st order LP filter up to maybe 125Hz, Bianco 12 with an LP at 500Hz, and SB20 with a HP above 500Hz.
All 1st order with some Rs/Rp for the SB20 if needed.
Is this a 2way or 2.5way or what?
- If you want to reduce the SB20 level you do it with the L-pad (Rs /Rp) just before the driver, not one Rs before XO and Rp after it.
- SB20 does not need a 2nd order XO with all the phase shift and inverted polarity, a simple 1st order will do nicely and also preserve the transperancy of the driver.
- even better if one uses a 1st order Series XO
- the bass - not sure what the role of R1 (5.1 ohm) is, is that the DCR of the coil?
- if that's so it is excessive and unnecessary.
- if you want to run it a 2.5way you need to arrange the XO differently. One usually wants a 2.5 so Baffle Step can be taken care off
- if you want to run it as a 2way you do not need two different drivers to cover the same range, a lot of stuff will go wrong
I would personally run Alpha 15 with a 1st order LP filter up to maybe 125Hz, Bianco 12 with an LP at 500Hz, and SB20 with a HP above 500Hz.
All 1st order with some Rs/Rp for the SB20 if needed.
I know, it's strange, as I wrote it's my very first xo - and it works to my ears pretty good.
It's a 2 way, at least it was my goal.
In the woofer section R1 has the role to attenuate the level because of the parallelled woofers. Further, I wanted to "adjust" the impedance graph, again, because of the double woofer.
Yeah, it's strange, but hey, this is my learning path, so strange things are expected to happen.
Nevertheless, thanks for your comment.
I'm already working on the next xo with in-phase drivers, maybe with different driver placement, another long way.
It's a 2 way, at least it was my goal.
In the woofer section R1 has the role to attenuate the level because of the parallelled woofers. Further, I wanted to "adjust" the impedance graph, again, because of the double woofer.
Yeah, it's strange, but hey, this is my learning path, so strange things are expected to happen.
Nevertheless, thanks for your comment.
I'm already working on the next xo with in-phase drivers, maybe with different driver placement, another long way.
Hi Istvan,
Nothing wrong with learning, even the hard way. It's all fun.
As a side note I spent a week in Vienna last September and loved it, discovered so many unknown to me things, and discovered Austrian beer, so underrated and so good. Having hard time finding some here down under.
Back to your topic - as a 2way you run into problems with IM distortion and time/phase shifts when 2 drivers cover the same range but are at different distances to the top driver.
Few ways dealing with the issue at hand:
1. if 2way is the aim remove one of the bass drivers, adjust the XO
2. if 2way is the aim do an MTM arrangement, adjust XO
3. convert to 2.5way (takes care of BSC)
4. convert to 3way (takes care of BSC)
In all cases no need for R1, it only creates losses and generates heat.
I personally am a big advocate of 1st order Series XO, which to me sound so coherent and natural and create the illusion as if you are listening to a single driver.
With the drivers you have you are in a great position to try that.
Bonus with 1st order Series XO - no need for Zobels, LCR traps and all other gimmicks that parallel XOs need to operate properly.
Of course there are drawbacks, every component affects everything, so carefull selection is very important. But being 1st order it makes life so much easier as there would be 4 reactive componets at most in case of a 3way, and less with 2 or 2.5ways.
If you post the .frd and .zma files for your drivers I can give you some ideas and diagrams in XSim about possible XO options.
Cheers
Stan
Nothing wrong with learning, even the hard way. It's all fun.
As a side note I spent a week in Vienna last September and loved it, discovered so many unknown to me things, and discovered Austrian beer, so underrated and so good. Having hard time finding some here down under.
Back to your topic - as a 2way you run into problems with IM distortion and time/phase shifts when 2 drivers cover the same range but are at different distances to the top driver.
Few ways dealing with the issue at hand:
1. if 2way is the aim remove one of the bass drivers, adjust the XO
2. if 2way is the aim do an MTM arrangement, adjust XO
3. convert to 2.5way (takes care of BSC)
4. convert to 3way (takes care of BSC)
In all cases no need for R1, it only creates losses and generates heat.
I personally am a big advocate of 1st order Series XO, which to me sound so coherent and natural and create the illusion as if you are listening to a single driver.
With the drivers you have you are in a great position to try that.
Bonus with 1st order Series XO - no need for Zobels, LCR traps and all other gimmicks that parallel XOs need to operate properly.
Of course there are drawbacks, every component affects everything, so carefull selection is very important. But being 1st order it makes life so much easier as there would be 4 reactive componets at most in case of a 3way, and less with 2 or 2.5ways.
If you post the .frd and .zma files for your drivers I can give you some ideas and diagrams in XSim about possible XO options.
Cheers
Stan
Hi Stan,
glad you liked Vienna, next time we could meet over a beer 😀
Thanks for the explanation. Yes, the position of the drivers is surely not optimal and I was sure I have time/phase issues 🙂 even if the thingie measures good and sounds good.
To your comments:
1. It worked not very well with just one woofer, there was simply not enough bass.
2. Is MTM the same as the D'Appolito arrangement? I tried it (not very consistently) and didn't like it, but I guess the fault was me and the different woofer drivers. But it could be one possible way to go.
3 and 4 could be interesting, but first I would like to stay with 2way.
During the trials I had many attempts with the drivers in phase, but I wasn't able to get a good midrange. But I'm ready to learn 🙂 so I will follow your recommendations. And will make a mix with my strange ideas
As soon as I have the flu behind me I will post/send the files.
Many thanks for your help in advance!
Cheers
Istvan
glad you liked Vienna, next time we could meet over a beer 😀
Thanks for the explanation. Yes, the position of the drivers is surely not optimal and I was sure I have time/phase issues 🙂 even if the thingie measures good and sounds good.
To your comments:
1. It worked not very well with just one woofer, there was simply not enough bass.
2. Is MTM the same as the D'Appolito arrangement? I tried it (not very consistently) and didn't like it, but I guess the fault was me and the different woofer drivers. But it could be one possible way to go.
3 and 4 could be interesting, but first I would like to stay with 2way.
During the trials I had many attempts with the drivers in phase, but I wasn't able to get a good midrange. But I'm ready to learn 🙂 so I will follow your recommendations. And will make a mix with my strange ideas
As soon as I have the flu behind me I will post/send the files.
Many thanks for your help in advance!
Cheers
Istvan
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Hi again,
tried to get the drivers in-phase and the xo not so complex, so here a possible (?) kind-of-Hirsch (??) xo with simulated frequency response and impedance graph. However, the impedance is very low, it starts from 4.5 ohms and is mostly at 6 ohms, so... higher would be better. Comments would be much appreciated
tried to get the drivers in-phase and the xo not so complex, so here a possible (?) kind-of-Hirsch (??) xo with simulated frequency response and impedance graph. However, the impedance is very low, it starts from 4.5 ohms and is mostly at 6 ohms, so... higher would be better. Comments would be much appreciated
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Hi again,
since I can't get rid of the resonance in the left speaker (and I tend to think that in this corner of the room there are bad modes and excessive bass that cause the membrane to resonate - a room treatment with absorber, diffuser, bass trap, etc. is already being planned), I've switched back to the Alpair 12P. And yes, the resonance is gone...
The driver now has a burn-in time of over 300 hours, well over the magical 200 - and sounds very, very, very good. To be honest, I would not have expected this development of the driver. So I think now that these are the better FR (without being sure).
The mids are finer, more detailed, the (audible) distortion seems to be lower, all in all a better overall presentation is offered.
The overall characteristic is completely different than the SB.
The Alpair is less superficial or spectacular, which can initially sound boring when listening casually, but no, everything is in the right place with the right proportions - the SB, on the other hand, cheats a bit here, and covers the - in my opinion - lower detail resolution with it liveliness.The best example is the drum brush - with the Alpair it is immediately recognizable, with the SB it sounds like an unpleasant noise.
There is one important difference in the lineup - now the FR's are on the inside of the speakers, not on the outside as before.
Nonetheless, I haven't given up on the SB - new baffles are coming, just one woofer (Eminence Alpha 15) and an in-phase xo. It is quite possible that the SB needs a different xo or positioning in order to be able to show the full potential.
The fun continues, more strange things to come 🙂
since I can't get rid of the resonance in the left speaker (and I tend to think that in this corner of the room there are bad modes and excessive bass that cause the membrane to resonate - a room treatment with absorber, diffuser, bass trap, etc. is already being planned), I've switched back to the Alpair 12P. And yes, the resonance is gone...
The driver now has a burn-in time of over 300 hours, well over the magical 200 - and sounds very, very, very good. To be honest, I would not have expected this development of the driver. So I think now that these are the better FR (without being sure).
The mids are finer, more detailed, the (audible) distortion seems to be lower, all in all a better overall presentation is offered.
The overall characteristic is completely different than the SB.
The Alpair is less superficial or spectacular, which can initially sound boring when listening casually, but no, everything is in the right place with the right proportions - the SB, on the other hand, cheats a bit here, and covers the - in my opinion - lower detail resolution with it liveliness.The best example is the drum brush - with the Alpair it is immediately recognizable, with the SB it sounds like an unpleasant noise.
There is one important difference in the lineup - now the FR's are on the inside of the speakers, not on the outside as before.
Nonetheless, I haven't given up on the SB - new baffles are coming, just one woofer (Eminence Alpha 15) and an in-phase xo. It is quite possible that the SB needs a different xo or positioning in order to be able to show the full potential.
The fun continues, more strange things to come 🙂
In some of the pictures of the top baffle there is very little material left between the top of the driver and the edge of the wood. In fact, in Post #43 there is no wood. The rim of the driver actually touches the top edge of the baffle. And there is very little wood at the bottom edge as well.
So the wood is very weak at those points and could very well be resonant as a result. A larger height baffle might help improve the situation.
So the wood is very weak at those points and could very well be resonant as a result. A larger height baffle might help improve the situation.
The baffle in post #43 was just the old trial baffle, not the real one. Nevertheless, in the real one there is only a material width of 3-4 cm, so not that much. However, the resonance comes from the cone and not from the baffle. The new baffle will be "much" higher and I think about to use plywood or even bamboo, will see how it works and sounds.
Hi again,
and... well, well, well... less is sometimes really more 😀
As I wrote earlier, yesterday I made a completely new xo, for the first trial with parts what I had in my pile.
This is an in-phase configuration, the woofer is the Eminence Alpha 15a the FR is the 8" SB (never give up).
The result? Thanks to the in-phase circuit, there is an unbelievable openness and clarity in the midrange and the treble is crystal clear and crispy. The stage is even more defined, the singing is beautifully articulated and the singer makes a step forward as I like it.
Surprisingly, the bass is great. Okay, I now have less of it, but it is very well defined, clear, deep (yes), although not as much as with two woofers. But they were two different woofers, wired strangely, and I'm sure they don't go together. Learned something again. Now I will play with measurements, tweaking the levels (but they seem to be okay, but let's see), and soon I will order the required parts and material for the baffles.
So much fun, again 🙂
and... well, well, well... less is sometimes really more 😀
As I wrote earlier, yesterday I made a completely new xo, for the first trial with parts what I had in my pile.
This is an in-phase configuration, the woofer is the Eminence Alpha 15a the FR is the 8" SB (never give up).
The result? Thanks to the in-phase circuit, there is an unbelievable openness and clarity in the midrange and the treble is crystal clear and crispy. The stage is even more defined, the singing is beautifully articulated and the singer makes a step forward as I like it.
Surprisingly, the bass is great. Okay, I now have less of it, but it is very well defined, clear, deep (yes), although not as much as with two woofers. But they were two different woofers, wired strangely, and I'm sure they don't go together. Learned something again. Now I will play with measurements, tweaking the levels (but they seem to be okay, but let's see), and soon I will order the required parts and material for the baffles.
So much fun, again 🙂
Okay... the sound is completely different, the SB makes music completely free, I would never have expected this difference. And the second best thing about it is the learning effect.
PS: Of course there are absolutely no resonances...
PS: Of course there are absolutely no resonances...
A short and uncomplete demo, recorded with my mobile phone, so...
Hi Plott,
Thanks for sharing your OB journey with us!
I’m looking for OB mids and I see you switched back to SBA, although you find better the MA ones.
My idea is to use the SBA Bianco 15” and to pair it with the SBA 8” as you did (maybe plus a tweeter from 2k).
In your opinion which one of these two FR drivers is better in mids and overall?
Greetings from HH!
Djordje
Thanks for sharing your OB journey with us!
I’m looking for OB mids and I see you switched back to SBA, although you find better the MA ones.
My idea is to use the SBA Bianco 15” and to pair it with the SBA 8” as you did (maybe plus a tweeter from 2k).
In your opinion which one of these two FR drivers is better in mids and overall?
Greetings from HH!
Djordje
I like it tonally and dynamically from about 80 Hz to 900 Hz - really good tone in particular. It’s lacking mid-treble depth (obviously with a forward character) along with textural delicacy and upper-freq. detail and air. It is however fairly dynamic/lively. Try comparing/contrasting with the Linkwitz LX521 to get a better idea of differences.
Notably you can hear the baffle/diffraction that sort of enlarges and diffuses the result in that 300-700 Hz range, though that is probably being highlighted by your recording (rather than listening in person). You might be able to mitigate some of that latter attribute with some 4” thick open-cell foam along the baffle edges (front and back), perhaps 20 ppi foam.
The Fostex 206 listened to about 20 degrees off-axis with a good high-pass filter above 300-600 Hz will give you quite a lot more textural delicacy and upper freq. detail and air (despite its poor dispersion like all larger full range drivers) - though remember to respect that high-pass filter and off-axis listening recommendation.
Notably you can hear the baffle/diffraction that sort of enlarges and diffuses the result in that 300-700 Hz range, though that is probably being highlighted by your recording (rather than listening in person). You might be able to mitigate some of that latter attribute with some 4” thick open-cell foam along the baffle edges (front and back), perhaps 20 ppi foam.
The Fostex 206 listened to about 20 degrees off-axis with a good high-pass filter above 300-600 Hz will give you quite a lot more textural delicacy and upper freq. detail and air (despite its poor dispersion like all larger full range drivers) - though remember to respect that high-pass filter and off-axis listening recommendation.
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Hi @Djoki , a little correction: I wrote I think the A12P is better, but I still don't know for sure. Further, I also wrote, maybe the SB requires a different xo, another treatment, whatsoever 🙂 And now I ended up with a completely new configuration which sounds really good (on my ears). So you can see, it's almost impossible to make a recommendation. Luckily, we can change everything until we like the sound 🙂
Hi @ScottG , thanks for your comment and the advice, I will take a closer look.
The demo... made with a cell phone, so the sound is not really meaningful, and as you wrote, the midrange is very highlighted. But it definitely don't lacking mid-treble and upper freq - based on a crippled cell phone recording it simply cannot be judged.
Listening to it is really fine, of course there is much room for improvement, and I will try some of them (as I also will try the A12P in this config too).
Fostex... sure, it's a great driver and I have other drivers on my screen too (Sonido, f.e.). My first goal was to use the cheapo SB and see (hear) what's possible (SB 49,- €, Fostex about 180,-€). But I think I will definitely try more expensive drivers too.
One thing makes me "proud", or at least I'm glad it's audible: your comment regarding tonality and dynamics in the "phone range". That's why I adore OB.
Hi @ScottG , thanks for your comment and the advice, I will take a closer look.
The demo... made with a cell phone, so the sound is not really meaningful, and as you wrote, the midrange is very highlighted. But it definitely don't lacking mid-treble and upper freq - based on a crippled cell phone recording it simply cannot be judged.
Listening to it is really fine, of course there is much room for improvement, and I will try some of them (as I also will try the A12P in this config too).
Fostex... sure, it's a great driver and I have other drivers on my screen too (Sonido, f.e.). My first goal was to use the cheapo SB and see (hear) what's possible (SB 49,- €, Fostex about 180,-€). But I think I will definitely try more expensive drivers too.
One thing makes me "proud", or at least I'm glad it's audible: your comment regarding tonality and dynamics in the "phone range". That's why I adore OB.
