[bellicon]

Thanks to Lynn Olson for this wonderfully thorough review of the Tone Tubby Red http://www.nutshellhifi.com/MLS//MLS6.html I’ve yet to hear any open baffle speakers but I’m very anxious to build a pair of them. But how compatible the Tone Tubby will be for my particular situation is the big question.

It’s really sad and just as surprisingly that there’s next to no one making reliable, good sounding HF/MF band ESL drivers for DIYers. There’s certainly none in the USA that I know of, at least who do it on a continual commercial basis. Please correct me if I’m wrong on this. But ER Audio’s 505 mini panels Mini Panels very much appear to be the real deal. http://www.eraudio.com.au/Mini_Panels/mini_panels.html The trouble is that I’ve never found anyone at any forum who’ve used 505s in OBs with Tone Tubbys. Of course, there are woofers that work well in OBs with the 505s, but none that I know of are Alnicos, and its clear to many that they do have a unique and pleasing sonic signature.

But would the 505 ESLs and a Tone Tubby woofer actually be compatible?

Why ER Audio doesn’t post their impedance at website is strange. But assuming the 505s’ nominal impedance is 8 ohms, and using the 8 ohm of the TTs, the only other parameter required to insure their compatibility would be their sensitivity, correct? Rob says the 505s are 88db. Lynn Olson said that the Tone Tubby Red is 97db, though I read 96db here http://www.lowther-america.com/page2/page12/page20/page20.html and 100db here http://www.tonetubby.com/specs/red-12-8.html

Thus, even with an averaged Tubby sensitivity of 97.6db, unless two-way active crossovers are used, there would appear to be a big problem with blending the levels
of these two drivers-a 9.6db difference.

On the other hand, as pointed out in the wiki report on ESLs http://en.wikipedia.org/wiki/Electrostatic_loudspeaker#Disadvantages , being line source drivers, the 505s’ SPL decreases by 3db per meter, while-comparatively-the SPL of point source drivers like the TTs decreases by 6db per meter.

So even if they are far from electrically compatible, does this mean that the 505s and the TTs are at least more acoustically compatible? Perhaps by an acoustical difference of only ~ 4.8db rather than an electrical difference of ~ 9.6db?

However, as that ~4.8db acoustical/9.6db electrical level difference between the 505s and the TTs would still be quite audible-and since I don’t want to bi-amp these speakers-what manner of attenuation do I impose on the TT’s that will cause the least damage to overall sound quality?

Are L-Pads the only way? And what penalties will I pay for using them?

I also should point out that my amplifier is only 25 wpc into 8 ohms and 40 wpc into 4 ohms. Damping factor is 40. On the other hand, my room is only 12 ft x 13 ft. And my ears can’t tolerate average SPLs more than 77 or 78db-if that much- at ~11 ft, at least in a room that small. Finally, if whatever OBs I build won’t do down below 65Hz, my pair of Jim Salk’s version of Brian Ding’s Rythmik servo subs will take over from there.

I’m really hoping that Rob’s 505 ESLs and the TTs can be a great match for my first venture into the OB speaker world. But in case there is not a sonically “non-destructive” solution that anyone can suggest for my situation, please try to suggest another 12 or 15” 8 ohm woofer with an Alnico magnet. And one with a high Qts, making it a good bass response performer in an OB. Thanks.

[Speedskater]

When did Lynn do that review?
All the other pages are 9 years old.

[Audiophile58]

 Why don't you check out the Omega Alnico -6  Loudspeaker? If you need Bass down past mid 40s HZ
Then get a good powered Sub. I did a lot of Modding with   a lot of trial and Error and the hassles involved .
These  speakers are very understated  and sound excellent.

I have owned several Omega Loudspeakers currently the Alnico -6. If you needed dual drivers that is possible
also . These are proven designs with Cabinets That are great looking and built to last.

[JohnR]

Thus, even with an averaged Tubby sensitivity of 97.6db, unless two-way active crossovers are used, there would appear to be a big problem with blending the levels  of these two drivers-a 9.6db difference.

Hi, an active crossover is one solution, another is the approach where an inductor starts rolling off the bass driver well below the crossover frequency. This provides compensation for the dipole/OB cancellation as well as the crossover, and can be used to match sensitivity.

On the other hand, as pointed out in the wiki report on ESLs http://en.wikipedia.org/wiki/Electrostatic_loudspeaker#Disadvantages , being line source drivers, the 505s’ SPL decreases by 3db per meter, while-comparatively-the SPL of point source drivers like the TTs decreases by 6db per meter.

The 505 panel is too short to be considered a line source. If you search for Jim Griffin's Line Array Whitepaper that will explain in great detail why. (If you stacked four of them, that would be a different story... )

[bladesmith]

L-pads are fine.... I use them in front of my tweeters. They make no degradation in sound quality.

[FullRangeMan]

According MJK the woofer should have about 10dB more than the FR.
This Tone Tuby driver is very high rate in price/value.
A alnico/hemp driver is a rare bird even today.

This Fostex 15 alnico woofer are priced in exxxcess of $3,236.00 and have the usual paper cone:
https://www.madisoundspeakerstore.com/approx-15-woofers/fostex-w400-a-hr-15-woofer/
This give a idea from howmuch special the Tone Tubby is for just $300.

[FullRangeMan]

According MJK the woofer should have about 10dB more than the FR.
This Tone Tuby driver is very high rate in price/value.
A alnico/hemp driver is a rare bird even today.

This Fostex 15 alnico woofer are priced in exxxcess of $3,236.00 and have the usual paper cone:
https://www.madisoundspeakerstore.com/approx-15-woofers/fostex-w400-a-hr-15-woofer/
This give a idea from howmuch special the Tone Tubby is for just $300.

Update Informing, on the Tone Tubby:

Scottmoose did like this ToneTubby driver:
Nothing profound. Based purely on the published data, it is what it is: a large guitar speaker likely intended for large sealed boxes or open back applications. Both the response trend and the electromechanical + mathematical T/S derivations are in line with that. Low electrical & mechanical damping, fairly high F0. The numerical sensitivity figure is high as they've presumably taken it at 3KHz where it's in massive resonance, or averaged across a select range. Probably the former. Not a unit I'd likely use for home audio purposes -fine no doubt for what it's designed for, which isn't the same thing. If you're thinking high Q unit for OB bass or similar, I'd be after one with a lower F0. YMMV as ever of course.

And MJK rhe same.

[matevana]

Update Informing, on the Tone Tubby:

Scottmoose did like this ToneTubby driver:
Nothing profound. Based purely on the published data, it is what it is: a large guitar speaker likely intended for large sealed boxes or open back applications. Both the response trend and the electromechanical + mathematical T/S derivations are in line with that. Low electrical & mechanical damping, fairly high F0. The numerical sensitivity figure is high as they've presumably taken it at 3KHz where it's in massive resonance, or averaged across a select range. Probably the former. Not a unit I'd likely use for home audio purposes -fine no doubt for what it's designed for, which isn't the same thing. If you're thinking high Q unit for OB bass or similar, I'd be after one with a lower F0. YMMV as ever of course.

And MJK rhe same.

Not exactly a glowing endorsement? I've used plenty of guitar speakers in OB but as a **midrange** driver. This is what Lynn was referring to in his "Beyond the Ariel" thread where he briefly considered using the Tone Tubby drivers. Also note the 1mm xMax in addition to the highish F0. This driver will be very limited in bass duties and will likely need to be highpassed to prevent over excursion. Remember that the lowest note on a guitar is about 88 Hz.

If you are hell-bent on the combination of alnico and hemp, check out the folks at Weber. They can build a variety of drivers and alter the magnet size, doping, cone material, and magnet construction to meet the need. And if I remember correctly are priced lower than the Tone Tubby stuff. Plus they have that vintage Jensen look and feel. 

[FullRangeMan]

Not exactly a glowing endorsement? I've used plenty of guitar speakers in OB but as a **midrange** driver. This is what Lynn was referring to in his "Beyond the Ariel" thread where he briefly considered using the Tone Tubby drivers. Also note the 1mm xMax in addition to the highish F0. This driver will be very limited in bass duties and will likely need to be highpassed to prevent over excursion. Remember that the lowest note on a guitar is about 88 Hz.

If you are hell-bent on the combination of alnico and hemp, check out the folks at Weber. They can build a variety of drivers and alter the magnet size, doping, cone material, and magnet construction to meet the need. And if I remember correctly are priced lower than the Tone Tubby stuff. Plus they have that vintage Jensen look and feel.

So you mean say Tone Tubby as midrange and hi freq driver?
If midrange only means you will use a tweeter, which mean a awfull 3way xover.
Lowther US use Tobe Tubby as woofer:

Ted Weber have many speakers, what are the good for hifi Full Range?

[matevana]

So you mean say Tone Tubby as midrange and hi freq driver?
If midrange only means you will use a tweeter, which mean a awfull 3way xover.
Lowther US use Tobe Tubby as woofer:

Ted Weber have many speakers, what are the good for hifi Full Range?

Lowther America uses a separate subwoofer for bass fill, and the Tone Tubby is crossed in series fairly high, around 300Hz, if memory serves. You can hear the driver playing well into the upper bass/lower midrange region. None of the 10 or 12 inch guitar speakers are capable of being used w/o a tweeter, which is why I'm suggesting they be used for midrange duties, if anything.

Weber offers a number of drivers, but most fall into two main camps. The warmer, late break-up, "American" style which can at times work well for home audio, and the early break-up "British" drivers modeled after the Celestion sound which would not be a candidate. They will also build one-off drivers to your specs, and allow you to select from any number of options. If you let them know you are interested in home audio use, they will steer you in the right direction. I have a friend who uses a pair of their custom made 10" alnico drivers in OB, flanked by a small super tweeter and an Altec 16" bass unit. The Weber provides support throughout its operating range but is electronically high-passed to prevent damage.     

With regard to three-way crossovers, I've never had issues with a single small cap on the tweeter crossed fairly high. Few if any phase issues and very transparent sounding. I cross most of my tweeters this way at around 15k.

[FullRangeMan]

I was unawre Weber made to order speakers, thanks for inform.
By chance do you know the price of this 10''speaker?

[matevana]

I was unawre Weber made to order speakers, thanks for inform.
By chance do you know the price of this 10''speaker?

I believe they were only around $100 each, which really isn't bad for a 10" alnico driver, made to order. He didn't opt for the hemp cone because he believed they were too heavy and wasn't as concerned with the ultra smooth break-up mode. He was able to specify things like dust cap material, magnet size, the amount of doping and even the basket color. I can tell you that paired with the "voice of the theater" Altecs, the combination sounds incredible. He is using a very small/inexpensive dome tweeter (Dayton ?) with minimal x/o components. 

[FullRangeMan]

Great its a steal. Thanks again.