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The mid drivers are 5.7 ohms.
The woofers are 8.3 ohms - they sit in the same chamber so they must be in series - and the wiring at the driver side agrees.
The Fountek 3.0 is spec'd at 7 ohms, and my change ended up putting a .9 resister (10 + 1) across the ribbon leads. I know that has more of an effect on the lower end of the spectrum and that's good, it was a little too hot around the xover ~4k
The midrange drivers are countersunk, I could find a mid to fit, but, I've always been happier with small diam mids like the 4" and 2.5" mids on the DQ-10 or the driver on the Verity Parsifal (5"), KEF 101 mid/woof. Also I was curious about the MTM alignment Steve favors with if not a Raal ribbon and pretty good ribbon. I could fit the MBR's I mentioned into the cabinet with about .3" to spare.
I could also remove the baffle that separates the mid from the woofers (with the MBR's using much smaller enclosures - but it would certainly detune the port, although as an acoustic suspension with another 30% or more volume.... I know without the modeling it would be a stab in the dark. So don't yell, I won't do it.
If I want to spend about $1500 I could just get the smaller BMR Philharmonic plus the flat pack (not the tower) kit and get a better sound. I know the 202's will never give me that. I'm not a huge fan of the deceased Peter Aczel - but he was right back in the early 80's when he said a great tweeter has the greatest effect on the sound vs a moderate quality mid and woofer vs one of the others being the best.
Thanks for any and all input.
The mid drivers are 5.7 ohms.
The woofers are 8.3 ohms - they sit in the same chamber so they must be in series - and the wiring at the driver side agrees.
The Fountek 3.0 is spec'd at 7 ohms, and my change ended up putting a .9 resister (10 + 1) across the ribbon leads. I know that has more of an effect on the lower end of the spectrum and that's good, it was a little too hot around the xover ~4k
The midrange drivers are countersunk, I could find a mid to fit, but, I've always been happier with small diam mids like the 4" and 2.5" mids on the DQ-10 or the driver on the Verity Parsifal (5"), KEF 101 mid/woof. Also I was curious about the MTM alignment Steve favors with if not a Raal ribbon and pretty good ribbon. I could fit the MBR's I mentioned into the cabinet with about .3" to spare.
I could also remove the baffle that separates the mid from the woofers (with the MBR's using much smaller enclosures - but it would certainly detune the port, although as an acoustic suspension with another 30% or more volume.... I know without the modeling it would be a stab in the dark. So don't yell, I won't do it.
If I want to spend about $1500 I could just get the smaller BMR Philharmonic plus the flat pack (not the tower) kit and get a better sound. I know the 202's will never give me that. I'm not a huge fan of the deceased Peter Aczel - but he was right back in the early 80's when he said a great tweeter has the greatest effect on the sound vs a moderate quality mid and woofer vs one of the others being the best.
Thanks for any and all input.
duc359, you did ask me to comment on your ideas. This project of yours raises all sorts of questions. It is not easy.
We don't even know what your existing crossover is. We are not sure what small BMR mids Dennis Murphy used in his speaker. 4 or 8 ohms?
You are right that smaller mids make the midrange clearer, being all about cone breakup being pushed higher in frequency.
Troels Gravesen does a very fine job in his SEAS 3 way Classic:
http://www.troelsgravesen.dk/3WClassic.htm
But swapping out drivers needs some skill and research. Also simming. Are you up to it?
We don't even know what your existing crossover is. We are not sure what small BMR mids Dennis Murphy used in his speaker. 4 or 8 ohms?
You are right that smaller mids make the midrange clearer, being all about cone breakup being pushed higher in frequency.
Troels Gravesen does a very fine job in his SEAS 3 way Classic:
http://www.troelsgravesen.dk/3WClassic.htm
But swapping out drivers needs some skill and research. Also simming. Are you up to it?
I did upload a copy of Visaton Boxsim 1.2 recently, since it is hard to get now, but has more driver files than Boxsim 2.0 :
https://www.diyaudio.com/community/threads/boxsim-full-system-design-from-visaton-free.267787/page-2
Off the top of my head, the FRS 8 M fullranger must be similar to your BMR idea:
https://www.visaton.de/en/products/drivers/fullrange-systems/frs-8-m-8-ohm
You could try modelling with it and see how it looks. You can also try some other visaton drivers to see how it all looks, especially on impedance..
The W170S woofer and SC10N tweeter spring to mind. But Visaton also do a ribbon type.
https://www.diyaudio.com/community/threads/boxsim-full-system-design-from-visaton-free.267787/page-2
Off the top of my head, the FRS 8 M fullranger must be similar to your BMR idea:
https://www.visaton.de/en/products/drivers/fullrange-systems/frs-8-m-8-ohm
You could try modelling with it and see how it looks. You can also try some other visaton drivers to see how it all looks, especially on impedance..
The W170S woofer and SC10N tweeter spring to mind. But Visaton also do a ribbon type.
The BMR Philharmonic has the 4 ohms (TEBM46C20N-4B - 3"). The one I figured would be better is a newer slightly smaller 2.5" 8 ohm version (TEBM54C30-8) that looks to have a similar profile in terms of FR - but is more efficient which would suit the 202 better I believe.
The crossover blueprint we are using does not include the thermistors FYI. There are 3 inductors on the board and another (the big bass one in the cabinet to keep it away from the rest of the board.
I have a technician level experience having done point to point testing and touch up (burnt pads, etc.) in my college days. I've upgraded tweeters and capacitors, and built kits like Haflers, Dynacos, and a Bottlehead Crack. I have a multi tester but it doesn't do inductance.
I certainly like the ProAc Studio 100's mentioned in the SEAS literature. The earlier EBS was one great speaker from back 40 years ago. Still I'd rather probably clean up the xover and get a better mid in the 202 since retirement has shrunk my reach for new audio purchases.
ADD: that visaton looks better than my suggested BMR. Thanks.
The crossover blueprint we are using does not include the thermistors FYI. There are 3 inductors on the board and another (the big bass one in the cabinet to keep it away from the rest of the board.
I have a technician level experience having done point to point testing and touch up (burnt pads, etc.) in my college days. I've upgraded tweeters and capacitors, and built kits like Haflers, Dynacos, and a Bottlehead Crack. I have a multi tester but it doesn't do inductance.
I certainly like the ProAc Studio 100's mentioned in the SEAS literature. The earlier EBS was one great speaker from back 40 years ago. Still I'd rather probably clean up the xover and get a better mid in the 202 since retirement has shrunk my reach for new audio purchases.
ADD: that visaton looks better than my suggested BMR. Thanks.
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Just started playing around with the visaton. Going to take time to get handy with it. I think the SEAS MCA12RC looks like the best reasonably priced mid - which you pointed too. So i'll play with that set of values, and look at the mid xover from the TG SEAS project. Also I will rebuild my xover to avoid the bi-wire input, and the metal core inductor use above the bass one, and I'll build it outside the speaker so I can do adjustments and just mount it on the back of the speakers.
Going from a high sensitivity driver like the triangle which is rated at 92db or similar, to an 86db driver, it will not work unless you are willing to pad everything down in order to match that sensitivity.
I thought it was 88 db, but yes 86 db is an issue. The charts and you say the woofers are a bit down in response, so with this driver, or something like it:
Scanspeak Discovery 10F/4424G @ 90 db. It is however 4 ohms, so that could require a resistor across the input to make it more in line w/ the other drivers, and a kinder load to the amp.
May not require a change to the woofer circuit. The tweeter already needs to be taken down in level, so a bit more won't matter much.
Another reason to rebuild the xover is to be rid of the thermistors (in my case the resistive replacements).
Scanspeak Discovery 10F/4424G @ 90 db. It is however 4 ohms, so that could require a resistor across the input to make it more in line w/ the other drivers, and a kinder load to the amp.
May not require a change to the woofer circuit. The tweeter already needs to be taken down in level, so a bit more won't matter much.
Another reason to rebuild the xover is to be rid of the thermistors (in my case the resistive replacements).
Hi, What is the different between the two version beside more driver files? I am start to like Boxsim been using Xsim.
Yes the mid enclosure is 855" or 14 liters - a smidge less if you subtract the ribbon getting mounted in that space vs the OEM tweeter. 13.55 w/ ribbon and 13.85 with the OEM.
vassilis 1984 pointed out the large size of the midrange chamber - nearly 14 L. Even a Fostex FE126NV which is 4.7" only needs about 2/3 of that, some of the BMR and other 3-4" drivers are a L or less. So no matter what the chamber size has to change, or just build/buy an enclosure to mount the driver over, and set it in.
Well I came up with a replacement mid - perfect shape. This fellow who I knew back in the late 80's had a pair of Pro Ac Response 2's set up and my Celius after the midrange went in sounded quite bad in comparison (Ribbons good, mids and lows - meh). Going to take my ribbons off, put the OEM tweeters back in, tighten it up, and give to my elder son for his basement system. Then concentrate on two more simple projects - Pro Ac Tablette and Cizek 1 restorations, while I look for a plan to build a knock off of something really good like a set of Response 3.5's, or the BMR Philharmonics. Thanks to all, and carry on.
I could not let my mods on this go at that. I took out the mid and tweeter, cut open the box in that area and mounted two BMR mids - the latest 2.5": Tectonic TEBM54C30-8 2-1/2" BMR Full-Range Speaker 8 ohms hooked in parallel vertically flanking a ribbon tweeter (Fountek Neo-X3.0).
I;m using the existing xover for the moment. I'm going to erase the traces of the bi-amping capability and use the existing pieces to wire as detailed by System7 in post #38. I believe the mids (not including the boosted low range from the open cabinet is maybe only 2 db less than the stock driver - of course I'll measure, but I may need some adustment to get the xover.box flat.
The two included pics are: 1: the way that they have been for some years. In my formally huge room at about 14' away the ribbon being so far from the mid resolved itself OK (the existing metal dome isn't hooked up). In 2: I've got the MTMWW alignment. The mids and tweeter are a bit too close to each other, so in nearfield (4') - they don't sound disembodied, but start to sound a little crowded at 7.5'. Also there is a ton of Sonex and batting behind the mids/tweet, and the tweeet is wrapped in 4 mm felt, but, the lower part of the mids is leaking thru the gaps in the cabinet. Since all that hides behind the speaker grill, I think I will cut the front mostly off, and anchor two two long open braces to house the properly spaced drivers (nice that the screw holes line up so nicely), and put the mids in an enclosure which is spec'd at .2 cu ft.
Also the 2nd harmonic on female voices, violins, guitars seem to exist in 3D space better than the the stock speaker, a result of going from the 6.5" stock mid in part I believe.
Comments?
I;m using the existing xover for the moment. I'm going to erase the traces of the bi-amping capability and use the existing pieces to wire as detailed by System7 in post #38. I believe the mids (not including the boosted low range from the open cabinet is maybe only 2 db less than the stock driver - of course I'll measure, but I may need some adustment to get the xover.box flat.
The two included pics are: 1: the way that they have been for some years. In my formally huge room at about 14' away the ribbon being so far from the mid resolved itself OK (the existing metal dome isn't hooked up). In 2: I've got the MTMWW alignment. The mids and tweeter are a bit too close to each other, so in nearfield (4') - they don't sound disembodied, but start to sound a little crowded at 7.5'. Also there is a ton of Sonex and batting behind the mids/tweet, and the tweeet is wrapped in 4 mm felt, but, the lower part of the mids is leaking thru the gaps in the cabinet. Since all that hides behind the speaker grill, I think I will cut the front mostly off, and anchor two two long open braces to house the properly spaced drivers (nice that the screw holes line up so nicely), and put the mids in an enclosure which is spec'd at .2 cu ft.
Also the 2nd harmonic on female voices, violins, guitars seem to exist in 3D space better than the the stock speaker, a result of going from the 6.5" stock mid in part I believe.
Comments?
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Looks like the BMR Philharmonic Towers keep the MTM in a tight vertical. I assume figuring the lobing of a ribbon is more likely the closest edge of the ribbon to midpoint of the mid, which at 4k is 3.39" which is close to what they and I have (and can adjust to meet). But the Tower from woof to mid looks like 1/2 a wavelength but on the monitor looks like a 1/4 wavelength. Interesting and thats as much as I can go - 1/4 wavelength.
I don't want to build the little .2 cu ft enclosures for them, but I can't leave them in the cabinet naked, so I'm thinking of having them sit in a small front only baffle with a thick piece of mohair or whatever they did with the mid-woof of the DQ-10. I;m cutting the front of the top portion of the cabinet (WAF), leaving the female pegs for the grille, and also having to cut the top of the speaker to protrude the top mid up an inch or two to get the 1/4 wavelength for the mid -> woof. Im also going to get the xover up above the woof cabinet, since I foresee lots of tweaking
The two BMR's won't play as loud as the old mid, and they are getting stressed at the bottom of their range with the nominal 400 Hz crossover @ 12 db. If I keep the 2nd order, I will have to slide it up in value, or do a 3rd order. changing the cap for the mid is much easier.
It is exciting and positive change because subtle cues and inflections are coming thru. I don't listen above 94 db peak, and usually lower so the volume issue shouldn't be an issue.
I don't want to build the little .2 cu ft enclosures for them, but I can't leave them in the cabinet naked, so I'm thinking of having them sit in a small front only baffle with a thick piece of mohair or whatever they did with the mid-woof of the DQ-10. I;m cutting the front of the top portion of the cabinet (WAF), leaving the female pegs for the grille, and also having to cut the top of the speaker to protrude the top mid up an inch or two to get the 1/4 wavelength for the mid -> woof. Im also going to get the xover up above the woof cabinet, since I foresee lots of tweaking
The two BMR's won't play as loud as the old mid, and they are getting stressed at the bottom of their range with the nominal 400 Hz crossover @ 12 db. If I keep the 2nd order, I will have to slide it up in value, or do a 3rd order. changing the cap for the mid is much easier.
It is exciting and positive change because subtle cues and inflections are coming thru. I don't listen above 94 db peak, and usually lower so the volume issue shouldn't be an issue.
Observations:
Fountek X3.0 + -5 db L-pad (7.6 ohms at 4k)
BMR TEBM54C30-8 (two in parallel with 2 10 watt .5 ohm resistor in series = 4.35 ohms (500 Hz))
Triangle woofers in parallel (4.15 ohms)
with the crossover described in post #38 means that the crossover points are at/near 420 Hz and 2730 Hz. Also the woof and mid are 2nd order and the tweeter is 3rd order.
Issues:
Fountek as pointed out here: http://www.troelsgravesen.dk/W15_Neo3.htm has a broad big rise centered at 1250 Hz that starts getting notable at 2k. The cut off at 2730 Hz is well too low to avoid that. Going up to 4k is about .55 octaves higher, but more to the point at 1.5k it will be down ~25 db.
The woofers are 6.5"each so moving up from 420 to 500 is 1/4 octave. A 3rd order L-W would have them with less output than the existing 2nd order at just under 600 Hz. and above, so that should be fine.
The mids are a problem because they are less efficient than the woof or tweet. Also having them working at -12 db at 210 shows strain at the low end. A 3rd order is complex, but with the -12 db point at ~310 (.56 octave higher) the low end of the BMR should be less stressed. The high end of the BMR's would not be down 12 db until 6365 Hz – according to the data I have in hand, that should be OK.
The BMR Philharmonic Tower is reported to be crossed over at 700 Hz (2nd order L-W) and 4th order at 3.9 kHz. (https://www.audioholics.com/tower-speaker-reviews/philharmonic-bmr).
Summary: These will never be the BMR Philharmonic Tower, but a 3rd order L-W at 500/4k will help make them better. I did have to get rid of the OG tweeter, but a nice silk dome – maybe a 1 ¼” would have been cheaper and fit the speaker better than the ribbon.
Fountek X3.0 + -5 db L-pad (7.6 ohms at 4k)
BMR TEBM54C30-8 (two in parallel with 2 10 watt .5 ohm resistor in series = 4.35 ohms (500 Hz))
Triangle woofers in parallel (4.15 ohms)
with the crossover described in post #38 means that the crossover points are at/near 420 Hz and 2730 Hz. Also the woof and mid are 2nd order and the tweeter is 3rd order.
Issues:
Fountek as pointed out here: http://www.troelsgravesen.dk/W15_Neo3.htm has a broad big rise centered at 1250 Hz that starts getting notable at 2k. The cut off at 2730 Hz is well too low to avoid that. Going up to 4k is about .55 octaves higher, but more to the point at 1.5k it will be down ~25 db.
The woofers are 6.5"each so moving up from 420 to 500 is 1/4 octave. A 3rd order L-W would have them with less output than the existing 2nd order at just under 600 Hz. and above, so that should be fine.
The mids are a problem because they are less efficient than the woof or tweet. Also having them working at -12 db at 210 shows strain at the low end. A 3rd order is complex, but with the -12 db point at ~310 (.56 octave higher) the low end of the BMR should be less stressed. The high end of the BMR's would not be down 12 db until 6365 Hz – according to the data I have in hand, that should be OK.
The BMR Philharmonic Tower is reported to be crossed over at 700 Hz (2nd order L-W) and 4th order at 3.9 kHz. (https://www.audioholics.com/tower-speaker-reviews/philharmonic-bmr).
Summary: These will never be the BMR Philharmonic Tower, but a 3rd order L-W at 500/4k will help make them better. I did have to get rid of the OG tweeter, but a nice silk dome – maybe a 1 ¼” would have been cheaper and fit the speaker better than the ribbon.