Augerpro
I replaced the woofs in my first set of AMT1Bs with a pair of AE TD12S. That is an awesome combo. I think I had the crossover set around 1000-1100. I stuffed that box with fiberglass and covered over the PR in the back, but that box was too small for me and the TD12S. You may need to build new boxes. PM me if you have any questions.
I replaced the woofs in my first set of AMT1Bs with a pair of AE TD12S. That is an awesome combo. I think I had the crossover set around 1000-1100. I stuffed that box with fiberglass and covered over the PR in the back, but that box was too small for me and the TD12S. You may need to build new boxes. PM me if you have any questions.
deja view??
Almost reminds me of these...
http://www.lacieg2s.ca/w3terra/ols/audion-9-02.htm
xcept w/linaeums, the driver seems to also be the waveguide, eh??
augerpro said:
Almost reminds me of these...
http://www.lacieg2s.ca/w3terra/ols/audion-9-02.htm
xcept w/linaeums, the driver seems to also be the waveguide, eh??
Lynn and all - thanks for your overwhelming interest !
Yes the roughly 15 x 30cm (one horn) dimensions given where meant as to be overall – this was one of the tight limitations Jean-Michel had to work with as I wanted it to match my roughly 30cm wide mid OB.
Main difference for “cylindrical wave” horns is the compromised mechanically stability of the contour IMO.
As it’s bent only in one direction it lacks rigidity compared to a three dimensional surface.
I had to learn it the hard way with one of my first DIY tries on horns - centuries back – which was a complete mess, although I did it in fibreglass with additional bracing.
This time I definitely made sure the prototype became rock solid – no resonant pling / plong / pluck at all - if I knock the contour.
If you are after a “price no object” project – should do great…
Have you outlined your findings somewhere in detail?
(measurements shown were take without that sexy kissing lips though)
No, at the moment I’m not concerned about vertical diffraction.
It even might help to blend smoothly to my mids arrangement when you look at diffraction horns that are designed to do that deliberately – and yes – the “natural” vertical directivity of the AMT seemed to be a good match for that kind of horn for me.
The main difference between directivity and lobbing I can see is that lobes are created by comb filtering resulting in a phase change between adjacent lobes – whereas directivity basically can be seen as a single lobe – or two (in exact opposite direction) in case of dipoles.
If the side lobes are at relatively attenuated level and only reach our preferred listening position after one or several reflections (ie delayed) – I think we can stay cool - depending on your goals and how picky you are at that very subject of course
Not sure for now – not enough time for listing - so many questions to answer
For me my whole OB-dualhorn set up has its strength in an airy presentation that does not lack substance – if that tells you anything...
Michael
gainphile said:
Yes the roughly 15 x 30cm (one horn) dimensions given where meant as to be overall – this was one of the tight limitations Jean-Michel had to work with as I wanted it to match my roughly 30cm wide mid OB.
Main difference for “cylindrical wave” horns is the compromised mechanically stability of the contour IMO.
As it’s bent only in one direction it lacks rigidity compared to a three dimensional surface.
I had to learn it the hard way with one of my first DIY tries on horns - centuries back – which was a complete mess, although I did it in fibreglass with additional bracing.
This time I definitely made sure the prototype became rock solid – no resonant pling / plong / pluck at all - if I knock the contour.
brucemck2 said:
If you are after a “price no object” project – should do great…
soongsc said:
Have you outlined your findings somewhere in detail?
augerpro said:
An externally hosted image should be here but it was not working when we last tested it.
(measurements shown were take without that sexy kissing lips though)
augerpro said:
No, at the moment I’m not concerned about vertical diffraction.
It even might help to blend smoothly to my mids arrangement when you look at diffraction horns that are designed to do that deliberately – and yes – the “natural” vertical directivity of the AMT seemed to be a good match for that kind of horn for me.
The main difference between directivity and lobbing I can see is that lobes are created by comb filtering resulting in a phase change between adjacent lobes – whereas directivity basically can be seen as a single lobe – or two (in exact opposite direction) in case of dipoles.
If the side lobes are at relatively attenuated level and only reach our preferred listening position after one or several reflections (ie delayed) – I think we can stay cool - depending on your goals and how picky you are at that very subject of course
augerpro said:
Not sure for now – not enough time for listing - so many questions to answer
For me my whole OB-dualhorn set up has its strength in an airy presentation that does not lack substance – if that tells you anything...
Michael
cuibono said:
http://www.diyaudio.com/forums/showthread.php?postid=1790568#post1790568
maybe this will help you so far - no idea if Jean-Michal's horns are scalable - maybe he will comment himself on that.
gedlee said:
Maybe - as said - its a matter of lobing versus directivity - but don't have time to do all necessary measurments - like to get a better feeling for the "sound" first - and so far I'm favourably impressed.
Besides that - we always have to deal with the tradeoff between mid-tweeter distance (the less the better) and available front area for the tweeter (the larger the better) with respect to the X-over wavelength - at least when it comes to SPL potent designs.
Audio is all about compromises - the dual horn approach is a "new" player in the game that might be worth for some further exploration.
The combination with OB is close to ideal IMO (and was the starting point) but for sure not the only beneficial combination we can think of.
What I have measured and hear right now has capabilities as PA speakers (especially in the en vogue line array configuration) as well - I'm confident it will find its right place / niche over time
Michael
augerpro said:
Mmmm... I don't know about 60L I just measured one (they are sitting upstairs with no drivers) and it looked to be about 11x11x23 internal dimensions. I didn't reach down to the bottom to measure, I know they are a touch bigger at the base, but by the time you take the driver volume into consideration I think it will be closer to 45L. The TD12M should handle the smaller box better, just get some fiberglass.
doug20 said:
This wasn't a final design, I got the things with rotted out woofers. When I was having the woofs refoamed, I had the TD12S sitting around doing nothing, I stuck them in, whacked out a basic crossover and they were very pleasent to listen to, overdamped box notwithstanding.
mige0 said:
In my opinion, the diffraction is visible in this pix:
An externally hosted image should be here but it was not working when we last tested it.
... the diffraction or its in axis equalisation, which is somewhat the same thing, is visble on the 10°, 20°, 30°, 40°; they are undulating, which is typical of horn diffraction.
thend said:
mige0 said:Courtesy Earl
OS wave guide at 0 deg:
An externally hosted image should be here but it was not working when we last tested it.
OS wave guide at 15 deg:
An externally hosted image should be here but it was not working when we last tested it.
OS wave guide at 30 deg:
An externally hosted image should be here but it was not working when we last tested it.
OS wave guide at 45 deg:
An externally hosted image should be here but it was not working when we last tested it.
48kHz Files provided by Earl I converted in CoolEdit and processed by ARTA to get CSD.
Looks pretty much excellent for me with respect to decay time
Michael
I can't see that much difference ?
Michael
Yes John - of course - the decay wasn't menat to show the parallelity, but the FR seen in the CSD of the OS too is rippled - as is seen in the double horn FR plots.
Besides that, I guess I would have to do measurements in the vertical plane to have a better grip on diffraction due to the finit cylinder shape (ig from the lips that are not needed in round horns).
The ripples in OS and DH show mostly mild HOM - reflection from mouth back into the throat (kind of cavity / transmission line resonance) - IMO.
But I think Earl or Jean-Michel could possibly comment better - and as said - sonic presentatin of double horn is - - wow...
Very curious what others findings may be...
Michael
Besides that, I guess I would have to do measurements in the vertical plane to have a better grip on diffraction due to the finit cylinder shape (ig from the lips that are not needed in round horns).
The ripples in OS and DH show mostly mild HOM - reflection from mouth back into the throat (kind of cavity / transmission line resonance) - IMO.
But I think Earl or Jean-Michel could possibly comment better - and as said - sonic presentatin of double horn is - - wow...
Very curious what others findings may be...
Michael
mige0 said:
Hi Michael
I think that its important to understand that not all resonances or standing waves in a device are HOM. In fact, since the non-HOM waves are by far the greater (or let's hope that they are - they will be in a "good" waveguide) its likely that many, if not most, of the ripples are NOT HOM. This is what makes measureing the HOM so difficult because they can only be detected from non-HOM standing waves and resonances by their dispersion, which, as John correctly points out does not mean longer decay time. They are only subtly different than resonances in the data, but they are not masked in our hearing as well as a resonance because of their dispersion.
gedlee said:
Thanks for pointing to the difference - I didn't get that before.
To be honest I didn't even get it now:
1 Are you saying then that HOM is detectable as there is decay *from* HOM whereas "normal" cavity resonace isn't (which can't be) or vice versa (then HOM should be nothing of serious concern IMO)???
2 Did you say that HOM and non-HOM ripples differ in dispersion - why does that make such a difference at one listening position - if equalized (despite power response)?
3 Which dispersion characteristic is the difference between HOM and non HOM reflections ?
4 what is the generating mechanism of HOM then other than the "half-mirror energy reflection" at the mouth which is the mechanism of any "normal" cavity resonace?
Michael
mige0 said:
All I says, the ripple response or worse; a comb filter response (depending of the delay of the diffraction(s)) are typical of horn/waveguide/tube diffraction.
This is visible on the impedance responce too.
Look at this PDF that we can see on my site:
http://sd-1.archive-host.com/membres/up/78070497537767987/Acousticaltube.pdf
(download a little slow)
thend said:
Ok, sure - i didn't expect direct radiation speakers behaviour in that respect from my double horn approach (its kind a horn after all
) - I was just smashed how good the double horn mimics the direct radiation speaker sound wise (plus providing huge gain at the right place as well)thend said:
Thanks - good stuff to think about - though I have no idea how to implement that other than cut a elliptic shape into the top and bottom plate of the cylinder horn - which for sure would compromise cut off frequency severely (to say the least)
Michael
mige0 said:
I don't think it's all or nothing. Perhaps you would get audible benefit from simply providing a nice radius on the top and bottom terminations of your wave guide. a little foam is worth a try too. It's easy in your case, as you can use the top and bottom parallel walls to hold a sandwich of several layers (small quantities are available in sheets).
Sheldon