DIY Tweets that are on par with Electrostats

[MrBoat]

The beryllium tweeters that Dennis Murphy and Jim Salk like, and are beginning to use, are made by Transducer Lab.

The slide show on the TL home page shows the variety of dome tweeters they make: beryllium, magnesium oxide, aluminum oxide, and fiber composite.

Somewhere I read that all those TL tweeters seemed to share a similar sound quality, including those not made with beryllium domes. I cannot remember where I saw that comment, but it suggests TL may have learned a thing or two about making good sounding hard dome tweeters regardless of the composition of the dome.

That's what I believe. At least in an audible sense. As measurement technology advances, I am sure the differences must seem pretty compelling for those wrapped up in the science of it all, but audible accuracy with sound reproduction has been around for decades. At some point, this becomes a lot of technical tail chasing, before having realized the full potential of what already exists.

That's all fine and well for those interested in that so I'm not knocking it. Just holding on to a little personal perspective before giving up on what I have already heard come out of some pretty amazing speakers.

 

[KEW]

In response to Annunaki's original question, I have been impressed more than once with how horns can often have a similar sound to planar speakers. My subjective impression is it has to do with speed and details which I feel make the sound just a touch more vivid than reality!

I can say I would never mistake my Focal speakers (with Be tweeters) for ML planar speakers.

I love the sound/look/concept of the ML's and would probably have a pair if they were not so pricey, but do not feel that they are so accurate as other speakers. For example, I believe the sound of a finger snap played over the ML's would be more crisp than a real finger snap! That crispness is seductive!

 

[KEW]

That's what I believe. At least in an audible sense. As measurement technology advances, I am sure the differences must seem pretty compelling for those wrapped up in the science of it all, but audible accuracy with sound reproduction has been around for decades. At some point, this becomes a lot of technical tail chasing, before having realized the full potential of what already exists.

That's all fine and well for those interested in that so I'm not knocking it. Just holding on to a little personal perspective before giving up on what I have already heard come out of some pretty amazing speakers.

The ideal dome speaker material would maintain its shape without distortion at any frequency it was asked to play.
Somewhere Harman Labs has some laser interferometer measurements showing how Be compares to several other materials. They use this as the case for Be tweeters, and it did indeed maintain its shape better than the other materials.
Be either is or is very close to the most rigid material with the lightest weight (for quick response).
Thus, in theory, Be is an excellent material for a dome tweeter. Is it really audibly better than the next best material? I don't know.
However, once you commit to making a Be driver, between the costs of
1. process requirements to safely handle Be
2. the Be, itself... being a rare material
3. purifying/forming the Be into a dome
it would be insane not to commit to the best available designs for every aspect of the tweeter assembly. Only a relatively large company with the resources (including a good engineering/design capability) could take this on.
My point is it is entirely possible that the reason Be has such a good reputation is that crappy Be tweeters were never produced.*

*This statement does not include the few "Be" tweeters that were made of an alloy with very little Be in them but sold as Be by unscrupulous manufacturers. Obviously, we are not talking companies like Harman-Revel, Focal, or Paradigm.

 

[MrBoat]

The ideal dome speaker material would maintain its shape without distortion at any frequency it was asked to play.

That's kind of where I picked up on this subject, thinking of a broad range of more common materials with distortion levels measured 2 and 3 places south of a decimal point.

On a positive note: The U.S. is the top producer of Be by a rather large margin. Something like 85%.

 

[lovinthehd]

http://geology.com/usgs/beryllium/

 

[KEW]

Harman gives their rationale for using Be on pages 14 and 15 of the 42 page Salon brochure.
(this brochure is a pretty decent read for anyone interested in speaker design considerations despite being marketing literature)
http://revelspeakers.com/tl_files/catalog//LuxuryCars/Revel/Manuals/Active/Ultima2/prod_145_634595542765965291_Revel Ultima2 Brochure.pdf

Focal discusses it here (without the depth Harman provides):
https://www.focal.com/en/beryllium-tweeter

 

[annunaki]

Thanks so far for all the replies. Many more things to consider/weigh in with.

For bi-pole options, is it recommended to do both the tweeter/mid in a 3-way or just the tweeter? I must admit that bi-pole is not something I have done much research with.

 

[lsiberian]

Thanks so far for all the replies. Many more things to consider/weigh in with.

For bi-pole options, is it recommended to do both the tweeter/mid in a 3-way or just the tweeter? I must admit that bi-pole is not something I have done much research with.

I personally did a full-range bipole. Andrew and Chris both swore by it as a design. Unfortunately it's a lot of work because you gotta make two full driver baffles. Of course these are fronts and not meant to hang on the walls.

 

[annunaki]

Ok, so I have been looking a bit closer at actual components for my reference pair of speakers. What are the thoughts on the driver options and how they may pair together?

Looking initially at a woofer to tweeter crossover point near 2.2Khz and a low to woofer point between 90hz-120hz depending on the woofer choice.

The crossover points will come as the final selection is made with drivers.

My goal is clean transparent performance from 20-20khz that will give me the open air sound that comes with an electrostatic panel.

I am open to other suggestions too but I do have to keep a reality check on my budget.

Tweeter: Mundorf AMT 23.1M1.1 C

Mid-woofer options:

Seas Excel W18E-001 (E0018) 7"

Or
Scanspeak Illuminator 18WU/8747T-00, 7" woofer

Or
Dual Dayton Designer series 7" in an MTM?

Low End:

Dayton Audio Ultimax 10" in a vented high fidelity alignment

 

[Verdinut]

Ok, so I have been looking a bit closer at actual components for my reference pair of speakers. What are the thoughts on the driver options and how they may pair together?

Looking initially at a woofer to tweeter crossover point near 2.2Khz and a low to woofer point between 90hz-120hz depending on the woofer choice.

The crossover points will come as the final selection is made with drivers.

My goal is clean transparent performance from 20-20khz that will give me the open air sound that comes with an electrostatic panel.

I am open to other suggestions too but I do have to keep a reality check on my budget.

Tweeter: Mundorf AMT 23.1M1.1 C

Mid-woofer options:

Seas Excel W18E-001 (E0018) 7"

Or
Scanspeak Illuminator 18WU/8747T-00, 7" woofer

Or
Dual Dayton Designer series 7" in an MTM?

Low End:

Dayton Audio Ultimax 10" in a vented high fidelity alignment

For the subs, depending on the use of your speakers, if it's for high fidelity music reproduction, I would rather suggest the Dayton RSS series of subs. The RSS265HF or the RSS315HF units would definitely perform better than any Unimax for that purpose.

I have used the RSS315HF-8 models in a pair of 3.25 cf vented cabinets with excellent results. If you could live with such bigger cabinets tuned at 22 Hz, you would not regret it.

At present, I am using one RSS390HF-4 in each of my three front cabinets with active bi-amping crossing over to mid-woofers at 190 Hz. They are installed in 7.5 cf enclosures tuned at 16 Hz for an F3 at 20 Hz. The results with those 15 inch subs are amazing.

 

[annunaki]

For the subs, depending on the use of your speakers, if it's for high fidelity music reproduction, I would rather suggest the Dayton RSS series of subs. The RSS265HF or the RSS315HF units would definitely perform better than any Unimax for that purpose.

I have used the RSS315HF-8 models in a pair of 3.25 cf vented cabinets with excellent results. If you could live with such bigger cabinets tuned at 22 Hz, you would not regret it.

At present, I am using one RSS390HF-4 in each of my three front cabinets with active bi-amping crossing over to mid-woofers at 190 Hz. They are installed in 7.5 cf enclosures tuned at 16 Hz for an F3 at 20 Hz. The results with those 15 inch subs are amazing.

Thanks for the reply! Ideally I wanted to keep my baffle profile narrower and so a 10" or dual 10" were all the larger I wanted to go. I have heard great things about the Reference series and have seen a number of designs using it. What I liked about the 10" Ultimax was the ability to get solid output down to near 20hz without the large amounts of volume to do it.

The Ultimax uses a motor assembly that should allow for as good or better control of the cone as the reference so I am not sure there will be any significant loss or tradeoff Ultimax vs Reference. Is there specific validation for using the Reference vs an Ultimax in such an application?

 

[Verdinut]

IMO, if I was going to purchase additional subs for serious music listening, I would not hesitate to go for the Reference Series Hi-Fi model again, as opposed to the HO model which is not specifically designed for music. I don't see why a RSS sub motor assembly would not control the cone motion, if you use an amplifier with ample current and a decent damping factor.

If you want solid bass down to 20 Hz, and you don't have the space or are facing a spouse acceptance situation, that is different. But it will be at the expense of faithful music reproduction with the Ultimax, which is more appropriate for movie sound effects and Drum & Bass electronic music. I know that we sometimes have to accept compromises.

Recently, I bought three RSS390HF-4 subs to install in my 3 front cabinets to replace Altec 416-8As. Before purchasing them, I had discussed with the president of Solen, a world renown crossover capacitor and inductor manufacturer and speaker distributor. He recommended the Reference Series HF sub for serious music listening. They sound amazingly faithful.

Perhaps you could verify directly with Dayton Audio or call Christian at Solen (1-450-656-2759). I am sure someone will be able to explain the difference in design, performance parameters and suitability for each product.

In any event, keep us posted with your future and interesting experience.

Cheers,