B&G ribbon links and pics

[ThomasW]

Here are some links to sites using various configurations of the B&G ribbons.

So people understand that I put my money where my mouth is. I'm working on a new speaker. It uses the RD-75, along side a open baffle, line array of 8-8" Eton kevlar mid/woofers (no Pat, you don't need to do this for them to sound good.) But remember my reputation is for "wretched excess".

These links are a result of correspondence I had with the builders of these speakers, and a link to a site that was a supplier

http://www.audio-x-stream.com/faqbase.html A great FAQ regarding planar speakers

http://www.audio-x-stream.com/frmst5.htmlclick on "BGC RG28" link

http://www.csulb.edu/~jwhittak/ This site is a massive site dedicated to the study of line array ribbons/planars

http://members.tripod.com/~mdarling/Photos/bg75.html

http://ic.net/~jtgale/douglass.htm

Below is a page on my personal site, where I put a picture and performance plots of Tom Perrazella's RD-75's. You will want to check these out

http://users.t-three.com/ttriff/page24.html

Enjoy
Thomas




theAudioWorx
Klone-Audio

[Pat]

Those links were great!
Seems that everyone is going for the RD-75...is there a reason that no one is using the smaller array?

If I don't have access to a good measurment system (like LAUD) will I be able to figure out the correct "notch" filter needed?

Thanks




Pat's Page

[ThomasW]

The RD-75 is the most popular because it's the the biggest. And as we know size matters, right?

The best "value" is the RD-50. Can you live with a speaker 55" tall, and about 8" wide?

It's your choice, any of them will sound very good. The larger ones have a better "sweet spot". The horizontal dispersion of all the ribbons is the same. The vertical dispersion is limited to the actual height of the ribbon. So the RD-22 will have a "sweet spot" 22" high. The RD-75 has a 75" high/tall "sweet spot". This is actually why they are the most popular.

Realize that if later you want to upgrade, you can use the RD-22's for surrounds.

The "notch filter" is included with the speakers.

FIY, all the B&G ribbons are "self shielding" so the magnets do not mess-up TV's.

Pat, I also have raw correspondence from other owners, those that didn't have websites or pics. Would you like me to forward copies of it to you?




theAudioWorx
Klone-Audio

[ThomasW]

http://www.wisdomaudio.com/toc.html

This is a separate company formed by Tom Bohlender. They only sell assembled speakers and they use special versions (not available to DIYers) of the B&G ribbons




theAudioWorx
Klone-Audio

[Phil Rose]

Geez! I took a look at the Wisdom site and the only price that I saw mentioned was $18K for the little pups. Kind of out of the reach of meer mortals I guess.

On the subject of your DYIs, I spent a bunch of time a year ago looking a the Audio-x-stream site and came to the conclusion that you really needed to play around with the cross-overs to get a smooth cross to the woofs and that the baffle was a real contributor to the sound.

What are your plans for addressing the significant bumps and wiggles in the B&G ribbons response curve? I did notice that the Carver ribbons had a special cross-over available that took care of their response peculiarities. Also the Carver's had a large baffle with woofers open-ended like the 8-8" Eton kevlar mid/woofers that you are going to use. Is that to give a bi-polar output and do you need 8 to get any decent low end extension?

Questions, questions!

I'd love to see some more details on what you're planning. Also, I really enjoyed looking at your Marquis clone and IB that you posted links for. GREAT job on all your speaks!

[ThomasW]

Hi Phil, thanks

The main problem is the bump caused by the ribbon resonance. This is solved by the notch filter included with the B&G ribbons. When Rudi B. was selling B&G, he offered a special modified Clearview active XO that did the same thing, I don't know if this is still an option.

Yes, the 8" Etons will be open baffle. They won't however provide much bass. I'm hoping they will go fairly strong to about 50Hz. I'm keeping my fingers crossed on this. I haven't had time to fab up a prototype baffle for them yet. I bought 8 drivers simply because that gave approx the same height as the RD-75. For the test mule I may just use 6 Etons and get a pair of the RD-50 ribbons.

I've been corresponding with several B&G users from the bass-list, some using mono-pole and other dipole configurations. None complain about problems with the frequency response. Some of their plots are quite flat, simply using the stock notch filter

It's interesting to see the differing baffle configs offered by B&G and Wisdom. Certainly very different approaches.

My plan is to use dipole baffle, trying several sizes and configs (symmetrical vs asymmetrical baffle sides). Also I have a supply of Fostex and Technics leaf tweeters. These may be used to augment the top end performance. The goal is to create something that looks similar to the Martin-Logan "Statement", but without resorting to electrostatic panels.

I think that the Carver ribbons are probably better, but since they aren't available, that leaves B&G.

As the project progresses from concept to test mule, I'll post some pics and performance plots.




theAudioWorx
Klone-Audio

[Bing Fung]

Great links Thomas! Why do some of the frequency plots (ie the B&G RD-75) get so ragged after 10kHz? Yet when you look at the Orca Ravens, the response of the upper end look smoother.




Bing

[ThomasW]

Bing

There's a big difference between a magnetic planar ribbon and a true leaf tweeter.

The Ravens are a true leaf, this means the diaphragm is a metal strip suspended between to strong magnets. In the case of the Raven rare earth magnets. These have a fabulous top end, but need very sharp XO's and they can't go very low, and are really expensive. The Raven 3 is rated to 500Hz but should probably be XO'ed at 750Hz-1KHz and costs $1650ea.

The B&G are magnetic planars, so they go much lower. 150Hz is the rating, but probably best XO'ed at 250Hz. They have a more ragged top end but only cost 1/4th that of the Raven. So as with all things in life there are compromises

If you want the best of both worlds, use the B&G's for midbass/mids then XO to the Raven 2, or use a line array of leaf tweeters like used in the VMPS or Genesis. The Maggie 1.6 would out class both these options for $1600/pr, but they are a physically larger speaker.

If you're feeling "flush" and want something VERY smooth checkout these

http://www.exero.com/metaxas/pages/masnewfiles/index.html

Click on the DIY link then scroll down and click on the "Emperor" link :B




theAudioWorx
Klone-Audio

[ThomasW]

Here's something I'm giving serious consideration to cloning

http://swanspeaker.com/products/system/dulcet/dc2.htm

The list price is $100,000.00

The raw driver cost to clone is as follows: 16 Eton 8" Kevlar drivers $1088, 2 B&G RD-75 ...?, 24 Hi-Vi Research ribbon tweeters $1920. Different ribbon tweeters could be used that would drop the price several hundred dollars.

So roughly $4000 for the drivers add a couple hundred more for the mid and tweeter XO's, and an active XO for the 8". So for say $4500 you get a pair of these :B

Sorry the price change from the first time I posted this. I missed the fact that they were using bipole tweeters. So it was necessary to add 8 more ribbon into the cost.




theAudioWorx
Klone-Audio

[Lexman]

Is it Christmas already? All this talk about ribbons, I wondered.

Good info Thomas, as usual. I swear this guy has a book of these URLs. Now, if we could just get some of them in the database. :B

Those last speakers were magnificant. I simply must have the plans for those bad boys!

Lex

[Bing Fung]

$1650ea for the Ravens? Owwchhh!

Dare I ask how much the Emperors would cost?




Bing

[ThomasW]

Bing

I haven't see a recent price list, but last time I saw one the Emperors were $45,000. That's in Australia. Shipping to Canada, + the Canadian taxes will increase the price just a bit :B

Lex

Are you serious about wanting the plans?




theAudioWorx
Klone-Audio

[Lexman]

Those things are breathtaking Thomas, and I would love to embark on a project like this someday. But I warn you, I would need extreme guidance!

Cabinet wise, what kind of cost would I be looking at?

Obviously, the drivers you could pick up in phases I suppose to difray the cost over time. Helluva lot of components to these babies, and what ohms are they designed to operate at?

Thanks,

Lex

[ThomasW]

Lex

These aren't anymore complicated that your woofers. They are just ALOT bigger/heavier

It would be best to build them in modular sections. A tower for the cone drivers, a planar "wing" for the dipole B&G ribbons and leaf tweets. They would just lock together when done.

The DIY cabinet cost would be directally dependent on the finish materials used. Built out of MDF and painted black $250 max. Built with real exotic hardwood veneer and mirror finished $$$$$

Oh, BTW these would need a BIG, BIG room to operate properly. Otherwise it would be like having a huge pair of headphones.

A smaller version could be build say targeting 55" tall. This could drop the cost by 1/3rd or more

They could be built to target 4-8 ohms/side. The woofer column can be a rectangle, triangle or 1/2 piece of sonatube. The mid and tweeter "wings" should be stepped back from the woofer baffle to time align them. None of the dimensions are really "fixed in stone". They are using a very wide front baffle to get max baffle loading.

So here ya go......quick and dirty







theAudioWorx
Klone-Audio

[ThomasW]

If anyone is seriously interested in making these or a 55" version email me.

The "real" version uses 6" drivers that cost $150ea in quantity. Madisound has some closeout Eton 8" kevlar drivers that are $68ea. I bought 8 of these and am going to make a line array, then measure the performance.

Also there are numerous good inexpensive 6" & 8" drivers available. These drivers are only working up to say 200-250Hz, so real expensive, state of the art units aren't necessary for good performance.

The supertweeters aren't really necessary unless very smooth HF response is desired. I'll look around for a inexpensive leaf.




theAudioWorx
Klone-Audio

[Bing Fung]

Thomas, that sounds like a plan. On the other forums the sono is king, on the HTG the "Thomas Ribbon Wave Guide" rings supreme!

Lets have a TRWG building party

Seriously, I could be interested in a 55" pair.




Bing

[ThomasW]

Hi Bing

Ok, as I recall you already have the B&G pricing, if not let me know. So are the 8" Etons in your price range, or do we need to find something more "reasonable"?

Also there are a couple of options regarding the woofer column. It can be built as a sealed enclosure, or open baffle. Open baffle drops the efficiency and ultimate bass response a lot. It does create that great dipole woofer sound. Sealed is just that. Either way, a sub is recommended for best performance.




theAudioWorx
Klone-Audio

[Bing Fung]

How many 8" etons would be required in the 55" model?

I do have the B&G pricing. would the RD 50's be used for the 55" model?

Humor me, what's the estimated cost for the amount of super ribbon tweeters required, as shown?

What type and cost is the required crossovers?

I don't know what a di-pole sounds like, so I don't know which one I prefer.

Geeze Thomas, you only need a sliver of an excuse to build a speaker... if any LOL I didn't mean ASAP.




Bing

[ThomasW]

Bing

6 midwoofers per side are best.

I ordered and have had the 8-8" Etons here since early August. So I'm pumped to check them out. There have just been too many other things to do.

There are some really nice non-shielded carbon fiber 6.5"-$21 (p/n 55-1545) & 8"-$31 (p/n 55-1550)drivers available from http://www.i-mcm.com They also have some very nice non-shield woven kevlar units 8"-$46ea (p/n 55-1590)

When Jon was here he took back his calibrated B&K mic and mic pre-amp. So I just ordered a relatively inexpensive 1/3rd Octave RTA, and need a reason to start using it.

Yes the RD50 is the ribbon of choice. Another option is the 45" from http://www.newformresearch.com The compromise with these is that they are monopole only, but they have a smoother top end compared to the B&G and are only slightly more expensive. Made in Canada

The Hi-Vi leaf tweeters are $80ea in lots of 4 or more. Might be able to cut a deal with the purchase of 12. I haven't been able to find a cheaper good leaf. There are some Phillips units that should be available, but as of yet I haven't been able to locate a North American source.

I'd recommend an active XO if the woofers are run open baffle. It's the only reasonable way to match the efficiencies. If a sealed box is used then passive XO with good quality parts probably $100/side max. This is just a guess!

The system could be built modular, starting with the woofer column and big ribbon. Listen for a while and if supertweeters are needed, these can be added at anytime.




theAudioWorx
Klone-Audio

[Bing Fung]

Thomas, thanks for that info.... A quick calculation indicates that it would cost about $2,624 for the parts, or $3,936 canadian. That's with the kevlar drivers, RD 50's, ribbon tweeters.

You know that's not bad considering what a person ends up with. Unfortunatley, I can't afford that right now Maybe I can sell some other stuff for this project, it sure interests me

The more I think of it, the more this is a great deal!

How do you begin to model the expected performance of this complex unit? What would not having the ribbon tweeters do to the response?




Bing

[Phil Rose]

Thomas,

I tried your Newform link above and ended up at a packaging manufacturer in Belgium. Would you please tell me what I did wrong.

[Bing Fung]

Phil, you did nothing wrong, try this link...
Newform Research




Bing

[ThomasW]

Bing

Thanks of fixing the link, see what happens when I post late at noc

Something to consider (like I need to add another variable in to mix), is that the Magnepan 1.6 retails for $1500. It's highly likely that these would give the ribbon hybrid a strong run for the money. Also the Maggie 3.6 $3750 might just smoke them totally. You could probably find either of these used in Canada for a reasonable price.

A way to use the 1.6 to max benefit is to use a good 10"-12" midwoofer, in a small sealed box running up to 250Hz. This will take the workload off the panels. The panels can just sit on the boxes as a stand. The price for this would be $2000 total including the price for new 1.6's




theAudioWorx
Klone-Audio

[Andrew Pratt]

Bing I can't speak for the ribbons Thomas is talking about but I can say I love my Maggies and I can't see myself going back to "normal" speakers anytime soon...and these are just the baby maggies.

[Bing Fung]

Whaa? Thomas, it doesn't make sense to go to all that trouble if something off the shelf would perform better.

I have always liked electostatic type speakers, but there certainly is something I like about cone drivers as well, some sort of texture to the sound if you will.

Thomas, what are the chances of cloning these?





Bing

[ThomasW]

Bing

Just chose your poison

Remember Maggies aren't an ESL, they are a type of ribbon.

The B&W's are just a 3-way bass reflex. Nothing magical about that. The molded fiberglass housing for the mid/woofer would be a real pain to copy though.

Actually I think you could build something quite a bit better using Eton midwoofers. I've used both the woven Kevlar drivers from ScanSpeak, and the Kevlar sandwich drivers from Eton. The B&W driver are woven.

I think the sandwich style drivers have a much better midrange. The woven kevlar have better bass, but in a 3-way that's not important.

When chosing a speaker design the intended use is important to consider. Most planars can't be driven to "reference" levels for HT. Now for most people this isn't really too big an issue because reference levels are too loud and do produce ear damage.

Cone drivers have more "slam (good for HT) but to my ears aren't as "real" sounding as planars. That's why I have the HUGE ESL's, and have been experimenting with the Whisper design. It has the cone slam, but it also loads into the room with alot of the "air and space" of a planar. Now that I've built the 1st Whisper clone, I now know how to build another using 1/2 the parts and with 1/2 the work and it will have 99% of the performance.




theAudioWorx
Klone-Audio

[Bing Fung]

Yes, I remember...

What if a person was to build a clone of the 803 series based on the eton drivers and say a ribbon tweeter in a separte housing? That would eliminate the need of the bubble.



I know it's nothing fancy, but it certainly would fit my budget...

Unless of course it cost more than the Maggies you have listed.

Tell me a bit more about the reduced cost Whispers..




Bing

[ThomasW]

Bing

That brings us back to where we started

The Etons are a strange driver. For an 8" driver, they have a very small magnet and voice coil. This is probably why they are a closeout.

I really need to work with them before recommending their purchase. I's not like they are going to sellout. Madisound as of last week had more that 100+ left, and these have been on sale for 9 months or so.

The "cheap" Whisper would be single 15"s top and bottom, instead of the dual compound loaded pairs. A large part of the Whispers cost and labor was fabricating the second baffle and using the second pair of 15"s. Then use a standard MTM configuration for the mid/woofer and tweeter. This is opposed to the 4 mid/woofers in the current config.

The standard MTM config would change the dispersion pattern. So again I'd need to mockup a speaker to make sure my guesses are correct.

Since I already have some of the Eton 8" I'll do an open air baffle, and a sealed box, then measure the performance. This will eliminate the speculation.

Oddly enough, any of the systems discusssed would cost the same, if not more than the Maggie 1.6's. These are a true "steal" for the price. This is why they are so backordered, it takes almost 6 months to get a pair.

One should remember that 1.6's are 19"X64"X2", so not small. And that dipoles dictate their placement in the room. So they aren't for everyone




theAudioWorx
Klone-Audio

[Bing Fung]

Thomas, it sounds like if the Maggies are a person's cup of tea, that it's very hard to beat them for the cost performance ratio. Even if you were to build, it seems as if the only reason to do so would be for pride and satisfaction.

As I told Andrew, I am a Cone Head but only because I'm ignorant to other types of sound transducers. It's been a while since I heard a pair of Dayton Wrights or Magnepans.

What I would really like at this point, ingnorant and all is something that copies the 803's. Could this be done with say the woven kevlar driver spec'ed in the BG hybrid, MCM PN 15-5090 and some scan speak or other bass drivers? All for a resonable cost?

If not I should just save for a while and continue to learn from your ideas, and when the account is right where I need it, unleash it on some super wild Thomas clone design




Bing

[ThomasW]

Bing

The 8" MCM is too big to be used as the mid in a 3-way, it will start "beaming" at the higher frequencies needed to XO to a standard dome tweeter. But the 6" (p/n 55-1585) should be quite good.

If you want something really sweet use 2-6"/side in a MTM config with a Focal TC90. This totals $306/pr. This would then be mated to a good 10" or 12" for fill from 250Hz down. So add another $200 or so. The factor in XO's and cabinets. These would sound better than the 803. I prefer MTM config over TMW. I prefer the dispersion of the MTM.

BUT something to consider in this exact price range is the Maggie MMG $500/pr, add a 10" woofer in a sealed cabinet/side (used as a stand for the MMG's) and presto GREAT sound for less than $800!




theAudioWorx
Klone-Audio

[Bing Fung]

Well it seems no matter how it is cut, the benchmark comes down to the Maggies. I certainly will need to hear a set of these to determine if they are for me. I'm really a cone head because of ignorance and poor genetic breeding. That and I really like cones, that's why my eyes popped out of my head when I seen those speakers above with all the drivers, ribbons etc :B

Surely Thomas, we(you ) could design some esoteric cone type of speaker system that would give me pride in design and craftsmanship, that would not break the bank and sound equally as good? If not, then this conehead may have to take off the dunce cap




Bing

[Pat]

I am in the same boat as Bing...I have never heard any Maggies or other planar ribbons...so until I can find time to make the 2 hour drive to the nearest dealer...it is hard to make a decision.




Pat's Page

[Andrew Pratt]

Guys get out there and listen to maggie sing she has a wonderful voice

[ThomasW]

Guys

I can certainly design a KILLER cone system. No problem, OK?

But it will cost more than the MMG's. Why? Because the MMG's are almost a "loss leader" for Magnepan to get people to try their speakers, and then trade-up to the bigger ones.

Pat, you can audition MMG's in your home for 60 days, if you don't like what you hear, they will give you your money back no problem.

Bing, I don't know how or if the MMG "deal" applies in Canada.

Now for a stone dead killer "box" start with a pair of the Focal TC120DX2 tweeters ($80ea). Then add 4 Eton 7-372/32 "heatpipe" kevlar midwoofers($151ea) and a quality XO and you're there for $1000/pr. If you bought this quality in assembled speakers they'd cost $3-4000/pr

Want ribbons with that order sir? B&G RD50 (you know the prices) with 4 ScanSpeak 21W8854 woofers($145ea) Total price about $1200/pr. These would exceed $5000 retail

Want something really reasonable? For the $500/pr budget, start with the MCM 8" woven kevlar (p/n 55-1590) use 2-8"/side in a MTM config with a Focal TC120.

All these will need a sub, that you all have.




theAudioWorx
Klone-Audio

[Bing Fung]

Now for a stone dead killer "box" start with a pair of the Focal TC120DX2 tweeters ($80ea). Then add 4 Eton 7-372/32 "heatpipe" kevlar midwoofers

Hauh, hauh hauh... Now your talking! I love that Heat pipe moniker, anything with a handle like that "Has got to sound good!" Just what is it ?

What about adding the Eton 8-800/37HEX to that above Thomas? I would like a system that does not require a sub. Since I have been subless of late, it's amazing how good my music sounds now. I guess if I made a sealed sub it would add nicely to the first plan with out being over bearing.

What would the required cabinet volume be for these Thomas?

Do you partition, separate the tweeter, mid, bass cabinets?

So if a person went the scanspeak ribbon route, doe the cabinet look like those newforms, stout with a highrise ribbon? Thats kinda cool too!

I haven't looked at the scanspeaks yet, will do that right now...




Bing

[Bing Fung]

Just looked at those Scanspeaks, that would be nice as well. looks like the response just rolls just before 50Hz.

I'm picturing a rounded back slim enclosure for the BG RD50 that is perched ontop of the rounded back cabinet for the Scanspeaks. add in a nice sealed sub... Nirvana! and all custom handbuilt...




Bing

[ThomasW]

Bing

The "heatpipe" is actually a heat sink that helps eliminate the voice coil heat.

For the MTM you wouldn't gain much adding a single 8" woofer. They simply can't displace enough air to be effective. Dual 8"s , single 10" or 12" on the other hand would be beneficial. This driver/drivers wouldn't need to be world class because of the limited frequency range.

The MTM configuration is simply one box, no subenclosures or dividers are needed. For the added woofer/woofers a partition and a bigger box would be necessary

If you build with a ribbon I'd suggest looking at these

http://www.soundlineaudio.com/html/sl_catalog.html

http://www.bgcorp.com/products.html#FLOOR

They are dipole, but your idea of a 1/2 tube, would be an excellent idea for a monopole. You could get a length of PVC pipe, split it and have a nice easy to build enclosure. It's takes paint fairly well. And is very easy to machine. For something really classy, black satin brushed metal is wonderful, but $$$$




theAudioWorx
Klone-Audio

[Bing Fung]

Thanks Thomas, those sure are nicely design units.

I suppose if the design was dipole it would lend to the openess or air?




Bing

[ThomasW]

Bing

Yes, dipole adds an "openness" and "air" or "space" that monopoles don't offer.

Remember with the B&G's they can be built either way. So making up a test baffle to compare the different designs is a relatively easy way to compare.




theAudioWorx
Klone-Audio

[ThomasW]

Just got around to modeling the 8 Eton 8" Kevlar drivers in a free-air baffle. Here's a look at the "sim"

http://users.t-three.com/ttriff/page31.html

theAudioWorx
Klone-Audio

[Pat]

Thomas,
Since you brought this thread back to life...
How do you think the B&G's would compare with Magnapans?
I had a chance this weekend to listen to some Maggies and I really liked them. I could have gotten a pretty good deal(I think) on a used pair of Magnapan III's.
I also got to listen to a pair of Martin Logan Ascents, Theil CS 2.3, Dunlavy Althena and SC-V's.

I liked the Maggies the best then the Thiels...After spending all day with a friend listening to these great setups, we went back to his place and tweeked his system then to my place and my friend doesn't think I need to build new speakers:? I am still undecided.




Pat's Page

[Bing Fung]

Thomas, that's a very nice response, How many eton drivers was that with?




Bing

[ThomasW]

Pat

Tough call, Planars vs Maggies. Sort of like do you want red wine or white? What's the price and which model of MG3?.

Bing

That's with eight. But the curve would be the same with fewer.




theAudioWorx
Klone-Audio

[Bing Fung]

Duuh, like the top of the graph stated "8 of the eton drivers" Which part of 8 didn't you understand..?

OK, here is another one.. Which BG ribbon?




Bing

[Pat]

Not sure of the exact model...I was "told" that this particular pair had just come back from the factory with basically new "everything" and they only had a few hours on them. They were asking $1675...also was "told" that new ones were about $4000.

I didn't know enough about the pricing to do anything so I just listened and nodded

Cool...B&G's are very close sounding to Maggies...I like...I like alot:B




Pat's Page