SALS?A! - a very long story

I must have a reliable stand for the speaker.
First I thought of doing it in 12 mm plywood:

An externally hosted image should be here but it was not working when we last tested it.


But on a second thought it will be it aluminium, cut out with my new CoreXY plasma cutter. It will be like a V on each side instead of the tripods.

Speaking of plasma cutter, here's how the front pole pieces are made.
 
In the end the stand came out like this:
IMG_3865.jpg


Black spray paint to cover the ugly welding:
IMG_3866.jpg


More than half of the cassettes have now been printed!

So soon as the glue and paint has cured/dried on the second stand, I'll start mount the cassettes.

I've managed to get more or less ten pairs of every color, that is 42 cm, so I think that I will mount five pairs a side.
But not in the same order.
 
Oh you gone filter them vertical to ??? what i meant was if used fullrange and let the pleat depth dictate how low/high it plays it still screws it up (like the headphone was designed) but i guess you power the tweeter (midle part) seperate. i once tried it with different pleat depths without filter.. and kind of got what i expected... not so nice response haha
 
I will make a rough guesses of the ratios tweeter/mid when I make the first couple of membranes.

Then I select the membrane with the best rough frequency responses.
I will then fine tune the frequency response for the two channels using convolution in Roon.

If I cannot get low enough cross feed between the tweeter and mid parts of the membrane,
I will have to make a retainer that separates them (and then make three membranes for every section instead of one).
 
As there can be a lot of membranes to connect, I bought some alligator clips:
IMG_3877.jpg

They are made of copper so they don't pull to the magnets.

They are so fantistatic that they require this bag:
IMG_3876.jpg

ESD sensitive, hmm.
But the distributor will never know if the bag will be near any ESD sensitive stuff.

I finally started with the gluing.
The cassette pairs don't want to be together, so I have to use clamps while the epoxy cures:
IMG_3883.jpg

I also have to wait for the curing before the next pair can be glued
 
Sorry for disappointing you but your driver will be not able to reproduce 1/3 octave pink noise around 90dB without large amounts of very disturbing noise!

Do not waste tons of money on idealistic projects , it's seductive to try something different but the involved physics are more complicated than you would imagine!

No transducer that cannot play pink noise without noise can be called high fidelity , therefore not suited for studio monitor application ...

but good luck anyway maybe you are the chosen one :)
 
I really like your project, with the best photos.
It is rare for someone to go to such lengths. Brave to discuss this in the forum.

How deep the AMT will run remains to be seen.
A professional AMT manufacturer once told me that 700 Hz was the lower limit. Unfortunately, I didn't ask why at the time.
There are certainly a few people in this forum who could physically justify such judgments. They should write here.
Greetings and good luck
 
I really like your project, with the best photos.
It is rare for someone to go to such lengths. Brave to discuss this in the forum.
The name of this forum is diyaudio. I think diy stands for do it yourself.
So there's no bravery in discussing this here.

How deep the AMT will run remains to be seen.
A professional AMT manufacturer once told me that 700 Hz was the lower limit. Unfortunately, I didn't ask why at the time.
I expect that the mid parts will measure better than the mid part of SLAM!:
With%20BPP%20Baffel%20behind%20Taped.jpg

Intended frequency range of the mid membrane is 350 Hz to 3400 Hz with -24 dB/octave filters.
So the professional AMT manufacturer perhaps wasn't a professional designer?

There are certainly a few people in this forum who could physically justify such judgments. They should write here.
No, there's only me and Båndsei.

Greetings and good luck
Thanks! Bear in mind that there are really nothing technically new with SALS?A! compared to SLAM!
The novelty is the cylindrical wavefront where I expect SALS?A! to outperform IRS 5.
The main reason for that claim is that the SALS?A! transducer is only 60 mm wide compared to IRS' much wider sets of transducers.
 
Okay, I got it.
Then I turn to you, as a layman.
How do you get down to 350 Hz? Has that to do with the depth of the wrinkles?
Particularly low resonance frequency? How is this accomplished?
The length of the spotlight won't be?
If so, why should a cylindrical shaft bring more depth?
What is the secret of the low frequencies.
thanks for your answers
 
Okay, I got it.
Then I turn to you, as a layman.
How do you get down to 350 Hz? Has that to do with the depth of the wrinkles?
Particularly low resonance frequency? How is this accomplished?
The length of the spotlight won't be?
If so, why should a cylindrical shaft bring more depth?
What is the secret of the low frequencies.
thanks for your answers
I have the cutoff frequency at 350 Hz, the transducer has to produce clean output for more than an octave below that.

Yes, the depth has to do with the frequency response but it is the width that really matters as the excursion increases with lower frequencies.
The side of the pleat (compare with the cone of a ordinary speaker) has to be stiff enough while the fold (compare with the suspension of an ordinary speaker) must be soft enough. Otherwise you'll get breakups.

Some resonances has to do with the geometric of the motor, it is hard to avoid that.
I have for instance different distance to the back pole piece for the tweeter part, so that the back wave reflection distortion is at a higher frequency.
The most of the resonances though, is due to the attachment of the membrane to the motor.
I've tried many things here, the "glue" has to compliant.

I don't know what you mean by spotlight and cylindrical shaft.

The secret isn't a secret, build a long AMT and you won't need that much of an excursion and use neodymium magnets.
The sensitivity of these speakers is above 100 dB at one watt and one meter.
 
The most of the resonances though, is due to the attachment of the membrane to the motor.
I've tried many things here, the "glue" has to compliant.

You have already tested a lot with the attachment to the engine. have you already tried thin rubber ropes? could you tighten them without hindering the sideways movement too much?
 
solhaga said:
The most of the resonances though, is due to the attachment of the membrane to the motor.
I've tried many things here, the "glue" has to compliant.

You have already tested a lot with the attachment to the engine. have you already tried thin rubber ropes? could you tighten them without hindering the sideways movement too much?
Yes I have in the early days of my AMT designs.
It didn't work.
Besides, I want the membrane to be attached to the magnets.