[Lynn Olson]

Aw shucks! 

Actually, I have to give Magnetar credit. There was a discussion in the "other" forum about him getting banned, one of the posters made a link to Magnetar's postings here on the AudioCircle "Open Baffle Speakers" forum, so I joined up so I could participate every now and then. I plan to keep posting on the "Beyond the Ariel" thread, but you folks have lots of good content in this forum as well.

Glad to see you here!

[painkiller]

I was actually just about to give an update on my project.

This is what I'm listening to right now. 


Drivers are Peerless XT dome tweeter with a 4,7uF series cap, crossoverless Tone Tubby Superboy 15" Bass for midrange and Eminence Alpha 15A with Grahams T-bass. The towel takes care of some upper midrange emphasis.  It's a very temporary setup, and I use about 6dB EQ above 5kHz and below 50Hz due to poorly matching drivers. So it's a big compromise to say the least.

First of all these speakers are so incredibly dynamic. The attack and decay is almost as good as with large horn speakers. They seem to shrink the soundstage a bit (like most speakers) on lower listening levels, but on realistic levels the soundstage opens up and becomes really lifelike. It's no problem playing at rock concert levels, and the speakers never seem stressed. My 55W monoblocks don't even get slightly warm. The speakers are very revealing, and the detail is among the best I have heard. Poor recordings are shown no mercy though. Especially those heavily dynamic compressed ones gives me a headache. 

I have never heard any boxed loudspeaker close to these speakers, at any price. It's tempting to compare them to the Avantgarde Duo/Trio. The big horns are somewhat faster and a bit more detailed, especially at lower levels, but they tend to blow up the soundstage to rediculous proportions at louder levels, where the OBs seem to portray a "correct" soundstage. I think I could get used to both. 

I get the impression that the textile dome doesn't match the Superboy sonic signature very well, and I'm hoping to get hold of some Fountek ribbon tweeters soon. I'd also like to try the Goldwood 18" bass drivers in addition to the Eminence Alphas. Exciting times ahead.

[Sjef]

I would seriously consider something else than a ribbon to mate with the Tone Tubby's. If they are really that dynamic, and I believe they are ( I know the 12" Alnico's are) then you will have a very hard time mating it with a ribbon. I haven't heard a ribbon to date, including the RAAL's that are dynamic enough. I have been trying the 12" TT's lately and they do not match with the RAAL's nor with the ESS AMT's, all not dynamic enough, wich leads to a the sound you desribe when you say that dynamicly restricted recordings start to sound really bad. Well they can sound better when your drivers are better dynamically matched. The dome tweeter you are using is in no way dynamic enough.

I have played around with some BMS 4540ND in custom made waveguides and they match the Tone Tubby's much better in every way than the RAAL ribbons do. I have only heard the big Fountek's once and heard the same dynamic restriction. Ribbons can have very good detail, in fact the RAAL ribbons I have are more detailed than the BMS tweeters when you listen to them stand alone, but put together in a system with the Tone Tubbys 12" Alnico the BMS reveals more detail and way more dynamics. The Raal's are better in the top-octave though but the crossover region here is much more important for the whole impact of the system. The BMS are pretty hard to use passivly,(and really need a little modification) as are any compression drivers in waveguides, so I use active waveguide correction on them. Do not try the variaty of very cheap horns an waveguides, like the to my ears quite horrible 18sounds or MCM waveguides that's what gives compression drivers a bad reputation.

well my own next step is to try the Raal ribbons with some old JBL2420 compression driver I have salvaged from an old PA system, they have a nice naturall roll-off at 11kHz, right where the ribbons are doing there best part.

There are lots of other compression driver out there, I have only heard a couple of them so don't take this as a direct recommendation for the BMS. While they are good and cheap there might be other interesting options as well.

[nullspace]

I've been having of a run of luck lately using the Beyma CP380M + horn w/ my TT 12"ers -- passive xover at 1.5kHz. I have some more work to do on the <100hz, but hopefully I'll post the full report before too much longer.

Regards,
John

[painkiller]

Thanks a lot for guidance on tweeters! It's very much appreciated.

It's very obvious that the dome tweeter is lacking the dynamic capabilities to match the TT. I have no experience with ribbons, but I thought that a large ribbon tweeter could be a good match? But perhaps I should start looking for compression drivers instead. That's a whole new area for me.

Any tips on how a good waveguide should look?

[Graham Maynard]

Hi painkiller.

LOL - looks like you've been exercising and thrown the towel over your speaker.

The towel will absorb, also break up aperture wave symmetry.

A fluffy paint roller will do the same - plus diffract mids/highs around the room to improve dispersion/ reduce beaming.
When the roller is closer to the cone it does a better job of minimising aperture dimension related peaks, and two rollers, one from above plus below, one covering part of the dustcap the other not at all, has always provided the best improvement adjustment for me.

Might be worth a try, and really does work with larger sized cone 'mid-rangers'.

Cheers ....... Graham.

[jeffac]

These 10 cm paper coned Saba tweeters might fit the hole and be worth a try. Check ebay Germany. I'm using them with a Saba 20 cm and B200 all run in parallel and they seem to hold there own in terms of sensitivity and speed. Open backed too which is a big plus as they supply almost equal HF rearward. Really quite impressive for circa 1955.

http://cgi.ebay.de/2-Saba-Alnico-Greencone-Hochtoener-Tweeter-5898010003_W0QQitemZ120312749564QQcmdZViewItem?hash=item120312749564&_trkparms=72%3A1275%7C39%3A1%7C66%3A2%7C65%3A12%7C240%3A1318&_trksid=p3286.c0.m14

[painkiller]

LOL - looks like you've been exercising and thrown the towel over your speaker.

And that's almost the case. It was a really quick fix, but it worked very well, so the towels stayed. I guess I'll be trying some better looking foam fingers when I get the time.

jeffac: Those Saba tweeters look awesome. I've been wanting to try a pair of those for a long time. But I doubt they can match the Tone Tubby's SPL. Do you have a datasheet for these drivers? Open back tweeters would really be a great addition. Like those $1000 () Gemini compression tweeters that Bastani uses.

[jeffac]

Hi Painkiller,

Yep they're pretty good from what I've heard so far. And you don't need to rob a bank like you might for those ribbons I'm not sure where you'd find T/S parameters, I stumbled across a discussion on the web once but can't remember where now. I posted a FR plot in Graham's LF boost thread, post #157
http://www.audiocircle.com/index.php?topic=53322.140
Lots of information also at the Lampizator site and from that and the FR plot, I'm guessing sensitivity in the 98dB+ range. As I mentined, I running mine with a second order filter, 4.7uf cap and 0.4mH inductor, in between a Saba mid and a B200 with Graham's paint roller mod for taming upper mids. A bit hot at the top maybe but I'm really enjoying the sound of this driver combination.    Still very much in the experimenting stage.

cheers.. jeffac

[Magnetar]

Aw shucks! 

Actually, I have to give Magnetar credit. There was a discussion in the "other" forum about him getting banned, one of the posters made a link to Magnetar's postings here on the AudioCircle "Open Baffle Speakers" forum, so I joined up so I could participate every now and then. I plan to keep posting on the "Beyond the Ariel" thread, but you folks have lots of good content in this forum as well.

Glad to see you here!

Thanks for bring that up Lynn, you are a real sport.

Maybe with a little work that can be accomplished here too

Have you given up on that project yet? Mating those different elements will be nearly impossible and you will never be satisfied if you still use live unampified music as a reference.

Do you have a working system yet?

[scorpion]

painkiller, jeffac,

I think this proposition is worth investigating, it is also what I suggested in reply #120 above to go with the TT Ceramics 8".
If I understand jeffac right he is using the tweeter in a MTM arrangement with B200 and Saba 20 cm Greencone.
Well, that's an interesting combo. I would think that either of those fullrangers would hold their own in an OB.

In Europe these tweeters are regularely sold on ebay.de and could be picked up for about 20-30 Euro the pair. Look up that you get the Alnico version,
there are also ferrit ones. I was fooled by one seller who delivered the ferrit version, luckily I also have a fine pair of the Alnico type but no Ceramics 8" yet.

/Erling

[scorpion]

Overreaction

/Erling

[jeffac]

Hi Erling,

Yes MTM but with the tweeter offset to bring the 2 fullrangers closer together, and mounted on the baffle rear to better time align with the B200. Will try them aligned vertically next test baffle and maybe positioned more toward the inside edge.

Painkiller, I hope you don't mind the slight OT, but here's a pic. FYI both Saba's have Dortmund Alnico magnets which I believe provide slightly increased SPLs compared to other types used by Saba.



cheers.. jeffac

PS apologies the pic is so large, first time I've posted one and still on L plates.

[Magnetar]

Lynn and Magnetar,

You are certainly welcome here. I think you should be aware of that people here also publish "on the other board".
As long as you don't consider this as a private playground, you are most welcome. However I smell some 'do I care' in magnetars answers,
as for his own propositions.

/Erling

I was under the impression all open forums are public playgrounds. Isn't that the purpose of this or is the forum intended for the purpose of dealers and manufactures to sell their goods?

What do you mean you smell some 'do I care' in my answers?

[scorpion]

You are certainly right that this is not a manufacturers playground, on the contrary.
What I was hinting on was the ignorance presented in the: HEEA! High Efficiency Electrostatic Array .

/Erling

[Rudolf]

I was under the impression all open forums are public playgrounds.

Erling was talking about "private" playground, which seems to be opposite to "public" playgrounds. So while we all should "feel at home", we "behave in the public".
Those Swedes seem quite anxious to have it real cosy at home.

[scorpion]

Edit

/Erling

[Magnetar]

You are certainly right that this is not a manufacturers playground, on the contrary.
What I was hinting on was the ignorance presented in the: HEEA! High Efficiency Electrostatic Array .

/Erling

What ignorance is that Erling?

[scorpion]

Edit

/Erling

[Rudolf]

Erling,

I had to read through that thread twice, before I got it. You really shouldn´t blame M. for not answering your question. Certainly no ignorance involved. One never knows in which way the man at the other end of the line has been interrupted or distracted after seeing your posting. And the next time he comes back to the screen even more questions and comments have popped up. I´m sure Magnetar will be pleased to comment.

Rudolf