Singular modified: curves not 45 degree (Singular)

by MikeH @, Saturday, February 24, 2007, 08:54 (3983 days ago)

I Listened to a friend's Singulars with AER drivers last week. (driven from 1 watt class A valve amp. First the efficiency amazed me, I wouldn't believe it was only a 1 watt amplifier. Then I sat in the right place and listened, it really opened my ears. I had a listen both with and without phase plugs and can't decide which I preferred. I noticed a difference in the mid-highs but I caNot put it into words.

I'm now fixated on building a single driver speaker for myself. It's time to retire my trusty old TaNoy M15s to the computer room.

All of my amplifiers are transistor amplifiers, reasonable but nothing special and certainly not class A.

I can't afford the AER drivers so I will have to settle for the Fostex FE207E.... for now. Then again I do want reasonable off axis performance so I might go with the 206.

I have decided firmly on the singular cabinet.
I initially decided firmly on Birch plywood, unfortunately that is impossible to get where I live. I can buy it but I am 1600km from the nearest city, by the time it gets here on a truck it will be damaged or broken.
So I have to use MDF. I will use 18mm for the internals and either 18 or 25mm for the outside.

I looked at the design and saw all of these corners inside. I would like to try something a little different if the experts agree with my thoughts.
Please excuse me for stealing the picture from your PDF.
First note the 50mm increase in height added at the bottom, this is if i use cement or similar to stop it from breaking in half.
The green part is a piece of hardwood, planed to a rounded shape, that part is easy.
The yellow parts are one of several things. Turned wood, sawdust and epoxy, cement, plaster, thin ply with sand packed behind, You get the idea. A material not too exotic or expensive that can be machined or poured into a mould.

question 1: would it improve the sound enough to make it worth the effort?
question 2: this would reduce the volume slightly, what is more critical length or volume?
Question 3: Which of the two fostex drivers, Just how bad is the 207 off axis?

[img]images/uploaded/image215.jpg[/img]

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Singular modified: curves not 45 degree

by Bert @, Monday, February 26, 2007, 16:07 (3980 days ago) @ MikeH

Hi Mike,

question 1: would it improve the sound enough to make it worth the
effort?

I do not think that it will improve much it could even turn out worse.

There is not much pressure in the column and the weigth of the enclosure is already heavy enough for stable placement.

question 2: this would reduce the volume slightly, what is more critical
length or volume?

Both are critical..

Question 3: Which of the two fostex drivers, Just how bad is the 207 off
axis?

Both are just as bad off-axis... the 206E has the advantage to be stronger (too strong) on axis but the net result when listening a bit off-axis is that there is more high frequency energy in the room making the sound less dull.

Ciao,

Bert

--
BD-Design - Only the Best!

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Singular: sand filling & plastic phase plugs?

by MikeH @, Monday, February 26, 2007, 23:29 (3980 days ago) @ Bert
edited by unknown, Wednesday, February 28, 2007, 02:36

Thanks Bert.
I will build it exactly as the plans show with all of the sharp edges. (they seem to help but I don't fully understand why)

Because I have heard the singular with the superb AER Mk1 drivers my expectations are now very, very high.

I will try hard to get some void free Birch ply, if I can I expect it will cost over 100 euro per sheet and I will have to take what I am given, probably with some voids. I can get good Marine ply here but I don't know how it will sound.

How does marine ply sound compared to Birch and MDF?
Some people fill the voids of the singular with sand, is this a good idea?
if it helped I would expect it might be mentioned in the drawings.

I noticed there are not many singulars in the Gallery. I will send you some pictures when they are built. I hope the red mahogany staining works out, it is rather difficult to do on Birch.

Bert: Are your acrylic phase plugs suited to the FE207E or do I need a different length for that driver? The material seems important, have you considered trying them machined out of acetyl plastic rod?

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Singular: sand filling & plastic phase plugs?

by Bert @, Wednesday, February 28, 2007, 09:51 (3979 days ago) @ MikeH

Hi Mike,

Better late than never... :blush:

How does marine ply sound compared to Birch and MDF?

Less dull...

Some people fill the voids of the singular with sand, is this a good idea?

If you want them to be more heavy then yes. There is not much pressure as with horns so no real need to fill that up.

I noticed there are not many singulars in the Gallery. I will send you
some pictures when they are built. I hope the red mahogany staining works
out, it is rather difficult to do on Birch.

Thanks, pictures are always welcome!

Bert: Are your acrylic phase plugs suited to the FE207E or do I need a
different length for that driver? The material seems important, have you
considered trying them machined out of acetyl plastic rod?

Those plugs do not fit in the 207/206's. I did experimented some though but their function is merely for front horn loaded drivers.

Ciao,

Bert

--
BD-Design - Only the Best!

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Singular: Thanks Bert!

by MikeH @, Wednesday, February 28, 2007, 23:00 (3978 days ago) @ Bert
edited by unknown, Wednesday, February 28, 2007, 23:12

Thanks for the advice Bert, I dont mind waiting.
I'm actually quite impressed you find the time to help people like me learn.

I like the singulars with the AER Mk 1 with the phase plugs more than without, but we didn't play with the crowns when I listened. (I had no idea what they did at the time)

So the wooden phase plugs it is. I might play with some copper pipe crowns later on. I think the biggest doubt I have is how my amplifier and 15 year old S-bit Yamaha cd player will sound with some good speakers.
The amp is about 5 year old - a quick class AB made by harman kardon, they call it "25 amp high current" which doesn't make a lot of sense to me, and I'm an electronics technician! The only practical reasons I can see is you can drive speakers with very ugly crossovers and it makes it easy to burn a speaker out if you run it into clipping.
I expect it will be rather harsh compared to the valve amp I heard.

If it sounds bad I will buy a T amp and build it into my cd player. A stealth T amp using the headphone volume control.
Then it's time to learn how these vacuum tubes work. I don't encounter them much in my work.

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