Another Unity Horn

[gedlee]

I'd better put my hand up here and say I disagree. ... I would never try that with the CD alone.

William

"I'd better put my hand up here and say I disagree."

I DO IT with a CD alone. Its more than possible, its eminately reasonable in any small to mid size venue. For large rooms, maybe not, but thats not the point of view here. We are talking about homes not theaters.

 

[Patrick Bateman]

Whats the goal, 60 x 40 control down to 750 Hz?

The goal is basically to have an enclosure which has a mouth that's the same size as the SH-50, but in a package that I wouldn't be embarassed to have in my living room.

The SH-50 has a square mouth measuring 28" x 28";
A 40x60 elliptical waveguide would require a mouth which measures 38" wide by 25.25".

That kind of footprint is anything but small, which is why I mocked up those pics of a design which is big, but blends into the corners to some extent.

If I finished the top and bottom with the same wood as I use in my floors, it might look little different than an elaborate table.

 

[cowanaudio]

G'day Earl

I have no technical issues with your design. I believe mine achieves a very similar final result, but takes a slightly different approach. If the Unity horns allow a crossover as low as 300Hz, and the system design requires that, then why not make the most of it? I have used my horns with a JBL 2226H and an 18 Sound 15LW1401 crossed at ~1K without the mids (DE25-16 compression driver) and at ~300Hz with the mids and these same 15" drivers. I could always get the system sounding better with the mids. I always felt the four horn loaded cone drivers did a better job of the 300-1KHz region than the 15" prosound drivers. Driver integration is also easier at the longer wavelengths. These 15" drivers needed a true subwoofer to supplement the low frequencies.

I now use 8 Peerless XXLS 12" drivers below the Unities, crossed at ~300Hz, without a sub as such. The system is simpler now (Bi not Tri amplified) and sounds as good as it ever has.

Cheers

William Cowan

 

[Sheldon]

Ugh so there's two people on the thread who've actually heard a "real" unity and they both agree it sounds best without the mids

Not quite, or at least that's not what I intended to say. I slightly prefer the Unity with the mids. But I would go with just the compression driver if I were starting from scratch, just because it's very good too and simpler. Cost/benefit.

Sheldon

I was reacting to your earlier statement

"If I take polar measurements of the horn and mid bass, I get something that looks very much like those on the Gedlee site. "

I guess that I don't see where this comment comes from. I might say that there are similarities, but I wouldn't say that they "look very much" alike.

Ah well, that's the problem with statements not tied to agreed upon quantitative standards. I see very few polar plots, so I'm more likely to perceive similarities. You see many and perceive the differences. I have to defer to the greater experience on this one. Can I say that there is at least a family resemblance for CD speakers, as compared to the usual box variety? The other similarity I perceived is a crossover zone between horn and the 15" driver, which is comparable to the Summa, or at least in the ballpark.

Sheldon

 

[Patrick Bateman]

The goal is basically to have an enclosure which has a mouth that's the same size as the SH-50, but in a package that I wouldn't be embarassed to have in my living room.

The SH-50 has a square mouth measuring 28" x 28";
A 40x60 elliptical waveguide would require a mouth which measures 38" wide by 25.25".

That kind of footprint is anything but small, which is why I mocked up those pics of a design which is big, but blends into the corners to some extent.

If I finished the top and bottom with the same wood as I use in my floors, it might look little different than an elaborate table.

A correction -

The dimensions of the horn are dictated by the distance from the throat to the mouth. So you can't simply scale the height by the width, which is what I did in the previous example. You have calculate it in one dimension, then the other. That works out to a elliptical mouth with dimensions like this:

Mouth Width = 40"
Mouth Height = 25.2"
Horn depth = 34.64" (part of this is chopped off to mount the compression driver.)
Coverage angle = 60 x 40 degrees
Mouth area = 791.7"
Mouth area of Danley SH-50 = 784"

The pic above used a mouth which was 30" across, so that would have to be scaled up. If I were to build this I'd use an elliptical mouth, not a square mouth.

 

[Sheldon]

G'day Earl

I have no technical issues with your design. I believe mine achieves a very similar final result, but takes a slightly different approach. If the Unity horns allow a crossover as low as 300Hz, and the system design requires that, then why not make the most of it? I have used my horns with a JBL 2226H and an 18 Sound 15LW1401 crossed at ~1K without the mids (DE25-16 compression driver) and at ~300Hz with the mids and these same 15" drivers. I could always get the system sounding better with the mids. I always felt the four horn loaded cone drivers did a better job of the 300-1KHz region than the 15" prosound drivers. Driver integration is also easier at the longer wavelengths. These 15" drivers needed a true subwoofer to supplement the low frequencies.

I now use 8 Peerless XXLS 12" drivers below the Unities, crossed at ~300Hz, without a sub as such. The system is simpler now (Bi not Tri amplified) and sounds as good as it ever has.

Cheers

William Cowan

I'm using Nick's 15" Lambda Apollo TDX (overkill I think), and they sound very good (and measure well) up beyond 1.5kHz. So crossing directly at 1.3kHz works well. I use two Lambda TDX 12" below, crossed in at 100 Hz. Next step, ala Geddes, is to add a couple more subs to fill in a few more room nodes.

Sheldon

 

[nickmckinney]

Ugh so there's two people on the thread who've actually heard a "real" unity and they both agree it sounds best without the mids

Reread my statement, in a home setting only.

Issues with the Unity mids, they make it an incredible pain in the butt to design a simple cabinet without a trap door hidden somewhere for installing the mids, and it does make for a seriously more complex and expensive system overall. They also make a top heavy speaker cabinet when the horn was simply placed on top of a single driver bass cabinet.

In a home setting you are in the nearfield of this horn, aka giant headphones (which I like) whether or not the mids are there. Outside of the home setting is very different.

Now in a home setting you can use a extended bandwidth 15" to get to the tweeter only and get enough clean SPL in room to be happy. The larger the room the better those mids start to work for you. I have heard them in a 5000 sq ft room and they work great there for instance whereas the simple 2 way is getting stressed. Once you get a 15" up to 1.5Khz or so and try to get xmax at the same time you start running into problems quickly. With the Unity we were able to use high excursion 15" drivers only up to 300Hz and it took 4 TD15X to keep up with a single Unity horn.

I still have 2 sets myself, the first prototype Tom made in his kitchen and a massive portable DJ style system with 12 bass cabinets. I won't be getting rid of either. However the horn with the tweeter only works down low enough and my drivers work high enough that they can be mated well enough for most tastes for home/studio use.

 

[gedlee]

Can I say that there is at least a family resemblance for CD speakers, as compared to the usual box variety? The other similarity I perceived is a crossover zone between horn and the 15" driver, which is comparable to the Summa, or at least in the ballpark.

Sheldon

Well yes, there are more similarities there to my designs than piston speaker designs. As to the crossover, I don't see any system plots so how can I tell if the system works right at the crossover. I only see individual drivers. The key is how does the system go together and work.

This discussion is becoming very much along the lines of comparing designs based on "it sounds good to me". These discussions get nowhere as they are never supported by any real data and of course your own design will always "sound good to you" so what's that saying. I would really like to see some valid data on the unity horns and the complete lack of any is a real concern of mine.

 

[GM]

GM

Beam width plots are not of much use to me. They are way way to coarse to tell anything important.

You're welcome! It's good enough to either confirm or deny yours and Pat's musings about the Unity's directivity control, but apparently my intent for posting it wasn't clear enough.

GM

 

[gedlee]

To me "directivity control" is far more than just beamwidth to some arbitrary level. What about everything in between these levels?

 

[GM]

What about them? I mean how are any high resolution measurement 'squiggles' in a WG's beamwidth response relevant to Pat's basic ~750 Hz directivity collapse (a bit high) or further clarify to any worthwhile degree how the Unity differs from your various assertions?

GM

 

[gedlee]

That data doesn't really clarify anything to me other than it doesn't seem correct. An 18" mouth should not be able to hold a beam below about 1 kHz, but I have no idea how that data was obtained. If I could see the full polar map then I would know for sure what was happening, but not with just a beamwidth plot.

 

[Sheldon]

Well yes, there are more similarities there to my designs than piston speaker designs. As to the crossover, I don't see any system plots so how can I tell if the system works right at the crossover. I only see individual drivers. The key is how does the system go together and work.

This discussion is becoming very much along the lines of comparing designs based on "it sounds good to me". These discussions get nowhere as they are never supported by any real data and of course your own design will always "sound good to you" so what's that saying. I would really like to see some valid data on the unity horns and the complete lack of any is a real concern of mine.

I'm not trying to prove anything, or make any claims regarding relative merit. It's not my design, and I don't have ego or money resting on it. Just a rank amateur.

I happen to have the Unity set up I describe. I don't have the Summas. At a gross level, the configuration of the two is comparable. Nick's horn with a good 15" midbass driver, and crossed at a similar point, and compensated for fairly flat response (in my case, slightly rising about 200Hz and slight roll off above about 10kHz), is similar in concept to the Summa. John (Patrick) has described the sound of the Summa. His description matches well with what I hear with my system (either as the Unity or as a conical CD waveguide). That's the data, such as it is.

BTW, Nick and Bill. I recommend that both of you try Dr. Geddes's foam. Subjectively, it "sounds good to me"

Sheldon

 

[Sheldon]

The plug itself. Goes to the phase plug on the TAD driver.

 

[Sheldon]

And FWIW, room measurement at the seating position, before any room EQ.

 

[nickmckinney]

Tom had a ton of polar plots of those horns at the time. The same Unity horn we used was also built by Servodrive with a 10" bass driver on either side and typically mounted on poles. Perhaps someone can find the data for those particular cabinets.

To be honest it sounds like there is a competition here between which design is better Gedlee vs Unity and IMHO both are good. Its like comparing a Z06 vs a Viper from my understanding of both designs.

Personally I want my horn with a TAD2001 compression driver mated to a Kapok cone ApolloTD15M that has a wee bit more xmax and these cabinets will be going in the corners and designed for such. Everybody wants something different I have learned, just look at how many different drivers I designed and people still want changes.

 

[Kravchenko_Audio]

To measure or not to measure?

I'm just an overzealous bumpkin compared to some of the people who post on this forum. My experience is confined to a few fields in audio reproduction. Cabinet design and transducer design. I'm a Phd nothing. More like Qualified By Experience (QBE) however narrow it may be. But I think that this is a fair statement :

From what I understand of the measurement question of Mr. Danley's products is this. All competitors measure the competition and try to learn from the results. The products Mr. Danley makes are available to the public. As are the products made by Mr. Geddes. They are even available to rent from some pro sound outlets. So why does't Mr. Geddes go out and perform the required tests to either confirm or deny his assumptions?

Mark

 

[gedlee]

Wish that I could afford the cost and time to make those measurements, but I can't. I have lots of competitive measurements, I just don't have those.

In a sense there is a competition of designs - there always is, even if they are all your own. I am very curiuos about the polar performance of the unity at the crossover from the mids to the tweeter, because if I understand this situation correctly this should be a problem. I have never seen data that tells me what I want to see. Most people don't take that kind of data. Polar charts at fixed frequencies or beam width plots don't tell me anything. I need a detail map of level versus angle and frequency. Nothing short ofthis data tells the story. We all talk about how the measurements "don't tell the whole story", well they don't if you don't look at the right measurements. If you look at the right ones they pretty much do tell the whole story.

The unity situation is similar to the dual diaphragm BMS driver which is so highly regarded. But at the crossover between the two devices the polars are pretty bad as they interact is very complex ways and this can be seen in the polars. On axis the transition is smooth, but off axis it is not. I expect the same thing in the unities.

Now in this competion it is important to note the "application". Both Tom and I would agree that the Unity is optimized for Pro sound in large venues where clustering is desired. My speakers are optimized for small rooms where there are lots of early reflections and where very high outputs may be required like in film. They are both going to excel in thier given applications, but there is an overlap of venues, and there it would be interesting to know the details of how the two stack up.

 

[Patrick Bateman]

Wish that I could afford the cost and time to make those measurements, but I can't. I have lots of competitive measurements, I just don't have those.

In a sense there is a competition of designs - there always is, even if they are all your own. I am very curiuos about the polar performance of the unity at the crossover from the mids to the tweeter, because if I understand this situation correctly this should be a problem. I have never seen data that tells me what I want to see. Most people don't take that kind of data. Polar charts at fixed frequencies or beam width plots don't tell me anything. I need a detail map of level versus angle and frequency. Nothing short ofthis data tells the story. We all talk about how the measurements "don't tell the whole story", well they don't if you don't look at the right measurements. If you look at the right ones they pretty much do tell the whole story.

I agree with these statements. The coaxial design is intriguing though. Based on what Sheldon and Nick said, a Unity with a 15" mouth doesn't offer any advantages over what I'm already listening to. (Summas.)

I'm in a mood to make some sawdust, and I'd like to retire my JBLs. I may take a crack at doing a unity with a 28" mouth, like the Synergy horn.

In that configuration, I would have two advantages over the "original" Unity. First, I'd get directivity control an octave lower. Second, I'd really like to do another project with the BMS 4540ND. That compression driver plays much higher than the B&C compression driver used in the original Unity. That's the compression driver I used in my last Unity clone, and it's audibly superior in the top octave when compared to the competition. Admittedly it runs out of excursion easily, but that's where the mids come in.

Basically it would be a unity where the upper crossover point is pushed up half an octave, and the waveguide goes lower than in the original.

Originally posted by gedlee The unity situation is similar to the dual diaphragm BMS driver which is so highly regarded. But at the crossover between the two devices the polars are pretty bad as they interact is very complex ways and this can be seen in the polars. On axis the transition is smooth, but off axis it is not. I expect the same thing in the unities.

You'll be horrified to find out that the Synergy Horn uses that very BMS driver, WITH mids right in front of it

There's a coaxial compression driver flanked by four mids, for a total of six diaphragms. It's basically a tri-axial!

Originally posted by gedlee Now in this competion it is important to note the "application". Both Tom and I would agree that the Unity is optimized for Pro sound in large venues where clustering is desired. My speakers are optimized for small rooms where there are lots of early reflections and where very high outputs may be required like in film. They are both going to excel in thier given applications, but there is an overlap of venues, and there it would be interesting to know the details of how the two stack up.

One of my pet peeves is eating at restaurants where they use home speakers to play music. I see this everywhere! Would love to see something like a Nathan sold to these restaurants, it would excel in that application.

 

[Sheldon]

Don't know if this helps, but here are some raw polar measurements taken in 10 degree increments, average of three sweeps (so not high res), 0-50 degrees. Taken at about 1 meter.

At around 1.5 kHz, the measurements stack in order, so you can follow the individual curves from there.

This is a passive crossover, and not particularly well optimized for the combination.

Sheldon