Not very far from me (swindon), thanks for the offer, and likewise (though mine is not in a very listenable state yet).
Doubt i'll be able to resist trying it as soon as i'm able to
. Won't be very solid by itself though. I need the heavy fill material too, got lots of BAF, but where to get the desnser materials?
Doubt i'll be able to resist trying it as soon as i'm able to
. Won't be very solid by itself though. I need the heavy fill material too, got lots of BAF, but where to get the desnser materials?
Ok, one rear chamber is basically finished. Don't underestimate the time/effort involved in making something like this . Reasonably happy with the results physically though.
MDF is off cuts, with only a jigsaw and router to deal with them. Basically cutting them roughly with jigsaw and using trim bit on router to deal with edges. Notice the little gaps as the bottom, the bit ran out of "guide" 
. Will need to be filled with something.
Brace isn't perfectly cut, hence the gap. Again, will try and do this more accurately next time but it isn't actually a major problem (lots of glue to hold further back). This actually uses a lot of glue too, need to buy some more. Quite a decent weight too considering its just pine and MDF, thought it would be more flimsy. Reaches back internally 30cm, volume about 7-8L (may measure accurately using the cut out sections).
Will need to test it for sound next, not sure how though.
. Reasonably happy with the results physically though.MDF is off cuts, with only a jigsaw and router to deal with them. Basically cutting them roughly with jigsaw and using trim bit on router to deal with edges. Notice the little gaps as the bottom, the bit ran out of "guide"
. Will need to be filled with something. Brace isn't perfectly cut, hence the gap. Again, will try and do this more accurately next time but it isn't actually a major problem (lots of glue to hold further back). This actually uses a lot of glue too, need to buy some more. Quite a decent weight too considering its just pine and MDF, thought it would be more flimsy. Reaches back internally 30cm, volume about 7-8L (may measure accurately using the cut out sections).
Will need to test it for sound next, not sure how though.
Attachments
Looking good, don't worry about the imperfections, no one will see it when it's all boxed in
Done a quick experiment with a stuff TL, this week. It was 600mm long, 1) because that was the width of the MDF and 2) I noticed that B&W have their tapered TL longer than 1/4 wavelength. It was a tapered TL, with an open end and medium stuffed with the monacor wool/poly mix. In comparision to the open baffle it didn't sound as open and 'natural'.
To me, when used open-baffle the Audax does show traits of electrostaic transducers (as mentioned else where, Neptune project?) which means that any non-amplified/electronic sound, i.e. voices, acoustic guitars sound very natural and open. But as with the electrostatic's I've heard, they fall over with electronic based music, OK the Audax doesn't do a bad job, but certain (not all) rock/electronic music did sound better in the TL.
Next weeks task it to try and do some measurements (with my limited ARTA skills) and attempt to redo the crossover to suit the Audax better.
With this testing I now really don't undertsand how the ATC mid's sound so good with no chamber or obvious rear wave control??
Done a quick experiment with a stuff TL, this week. It was 600mm long, 1) because that was the width of the MDF and 2) I noticed that B&W have their tapered TL longer than 1/4 wavelength. It was a tapered TL, with an open end and medium stuffed with the monacor wool/poly mix. In comparision to the open baffle it didn't sound as open and 'natural'.
To me, when used open-baffle the Audax does show traits of electrostaic transducers (as mentioned else where, Neptune project?) which means that any non-amplified/electronic sound, i.e. voices, acoustic guitars sound very natural and open. But as with the electrostatic's I've heard, they fall over with electronic based music, OK the Audax doesn't do a bad job, but certain (not all) rock/electronic music did sound better in the TL.
Next weeks task it to try and do some measurements (with my limited ARTA skills) and attempt to redo the crossover to suit the Audax better.
With this testing I now really don't undertsand how the ATC mid's sound so good with no chamber or obvious rear wave control??
A fair way into building the second mid chamber now. Also got the wood for the outer box cut too.
I tried the first chamber out with a crudely attached baffle. It isn't so obviously different to the test box as I might have expected. It is difficult to tell in mono/mismatched stereo pair though. Resonances arn't eliminated, in the lower ranges it's very clear but near the top it still have some fairly noticeable resonances. I'm unsure if this is coming from the cabinet walls, hopefully it is so that the sand fill will take care of it. It would sort of make sense since the unsupported wall areas are now smaller so thier resonances will move up, but the chamber feels quite well built and not too resonant.
Interestingly, speaking into the chamber sounds quite different to the test box, in fact the chamber doesn't seem to exist acoustically, its just like speaking into the open air (with lambswool stuffing). The test box sounds, well, like a box. I think a lot of voice range is below the 400hz crossover point though so it shows up the differences more.
A basic test for frequency response was carried out using a wave editor and sweep generator. Mic is Panasonic capsule ran through mixer to line in (normally use these mics for recording). Both speakers had the mic placed near to them and the sweep run at a fairly high level (think it was 400-4200hz or something). Both located same in room. The picture shows the test box left and new chamber right. Rolloff toward the top will mainly be from the active crossover which remained in circuit.
Interesting test you did, I expect the longer line is more ideal but I didn't want these to go so far back and adding any bend would be difficult/compromising. I'll use these mainly for electronic and rock so the TL seems a reasonable choice . Good point on the ATC, can't be space for much more than just thin felt and that dome will let reflected sound back through it very easily.
Also, anyone know ehere to get 1.5-2mm thick rubber sheets? Hardish type, heavy stuff. There isn't much space above and below for the sand fill (due to design and a cut being 3mm off at the shop) so I think rubber would work better here.
I tried the first chamber out with a crudely attached baffle. It isn't so obviously different to the test box as I might have expected. It is difficult to tell in mono/mismatched stereo pair though. Resonances arn't eliminated, in the lower ranges it's very clear but near the top it still have some fairly noticeable resonances. I'm unsure if this is coming from the cabinet walls, hopefully it is so that the sand fill will take care of it. It would sort of make sense since the unsupported wall areas are now smaller so thier resonances will move up, but the chamber feels quite well built and not too resonant.
Interestingly, speaking into the chamber sounds quite different to the test box, in fact the chamber doesn't seem to exist acoustically, its just like speaking into the open air (with lambswool stuffing). The test box sounds, well, like a box. I think a lot of voice range is below the 400hz crossover point though so it shows up the differences more.
A basic test for frequency response was carried out using a wave editor and sweep generator. Mic is Panasonic capsule ran through mixer to line in (normally use these mics for recording). Both speakers had the mic placed near to them and the sweep run at a fairly high level (think it was 400-4200hz or something). Both located same in room. The picture shows the test box left and new chamber right. Rolloff toward the top will mainly be from the active crossover which remained in circuit.
Interesting test you did, I expect the longer line is more ideal but I didn't want these to go so far back and adding any bend would be difficult/compromising. I'll use these mainly for electronic and rock so the TL seems a reasonable choice
. Good point on the ATC, can't be space for much more than just thin felt and that dome will let reflected sound back through it very easily.Also, anyone know ehere to get 1.5-2mm thick rubber sheets? Hardish type, heavy stuff. There isn't much space above and below for the sand fill (due to design and a cut being 3mm off at the shop) so I think rubber would work better here.
Attachments
This seems quite promisingDr.EM said:
Sounds that are meant to sound hard/rough, such as an electric guitar with a metal pedal set to 11, does loose out slightly on the open baffle. The same again with heavy synth work but if the track has any natural items, even voices these do sound more natural and 'better'.
I'm slightly torn myself between the openness of the open baffle and the abilty of the TL to allow electronic music to sound more hard/rough when needed.
No more progress on my own mid-range as I've been pushing forward on the bass cabs.
Been a while as I have been procrastinating over those awkward cutouts. What I'll be doing is making a sub baffle to fit over the drivers frames later, hopefully from acrylic or similar
For now the drivers are surface mounted. I have began boxing in the chamber. Nearly finished with the first one. Basically all the voids you see will be filled with sand. Between the top and bottom of the mid chamber are rubbery floor tiles, works quite well, very dead to a knock test
A capacitor for tweeter protection resides in the right hand void in the box, this won't be filled with sand. Left side only has 23mm gap but hopefully will be enough. Baffle is 12mm MDF and 12mm Ply bonded together, will be joined by about 6mm acrylic or similar eventually for the front. Area for the tweeter is routed out, its very flat and is contained entirely inside this baffle; an 18mm MDF board is behind this area because otherwise it'd only be 4mm thick
This won't look too pretty so hopefully it all performs nicely
Top being clamped on now
For now the drivers are surface mounted. I have began boxing in the chamber. Nearly finished with the first one. Basically all the voids you see will be filled with sand. Between the top and bottom of the mid chamber are rubbery floor tiles, works quite well, very dead to a knock test
A capacitor for tweeter protection resides in the right hand void in the box, this won't be filled with sand. Left side only has 23mm gap but hopefully will be enough. Baffle is 12mm MDF and 12mm Ply bonded together, will be joined by about 6mm acrylic or similar eventually for the front. Area for the tweeter is routed out, its very flat and is contained entirely inside this baffle; an 18mm MDF board is behind this area because otherwise it'd only be 4mm thick
This won't look too pretty so hopefully it all performs nicely
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Top being clamped on now
An externally hosted image should be here but it was not working when we last tested it.
Finished, apart from veneer etc, one speaker
Sand fill makes the weight up to about 30kg. I don't intend it to be perched atop the B&W too long; need to make progress on the bass cabs.
An externally hosted image should be here but it was not working when we last tested it.
Sand fill makes the weight up to about 30kg. I don't intend it to be perched atop the B&W too long; need to make progress on the bass cabs.
Sorry for not updating this. In response to your question, certain aspects were certainly better than the B&W's, but without the woofer or a pair a direct comparison is difficult. There was an issue with "resonance" in this, I can't figure out how since that cabinet is like knocking on solid stone. Must be a cone edge resonance or similar?
Anyhow, after hearing some I decided I prefer metal (hard) coned drivers and am doing a new design with the Dayton RS52! I will start a new thread for this when I have something to show (after weekend sometime hopefully, I will be routing the faceplates). Same tweeters being used, bass will be Hi-Vi M8a and eventually dipole subwoofer system too
Anyhow, after hearing some I decided I prefer metal (hard) coned drivers and am doing a new design with the Dayton RS52! I will start a new thread for this when I have something to show (after weekend sometime hopefully, I will be routing the faceplates). Same tweeters being used, bass will be Hi-Vi M8a and eventually dipole subwoofer system too
Rather than start a new thread, I thought I'd bump this and mention that while CAD Audio in Denmark has shown a good range of Audax units in stock for some years, including HM10Z)s, Madisound in the USA now show HM100ZOs in stock too, along with more of the carbon fibre and aerogel units than before. Pictures show 'Audax' rather than 'AAC' labels on most of the drivers listed by Madisound, so I don't know if these are newly manufactured or NOS. Interesting though.
I've had four of these for a couple of years and haven't used them, but I've finally set up a pair of there to test in a small open baffle along with RAAL 70-10Ds. It's good to know that spares are still available if it turns out I like them. No affiliation with Madisound BTW except as an occasional customer- I just thought American builders might be interested if they hadn't noticed this. The drivers I have were purchased from IPL in the UK, but AFAIK I had the last pair from them.
I've had four of these for a couple of years and haven't used them, but I've finally set up a pair of there to test in a small open baffle along with RAAL 70-10Ds. It's good to know that spares are still available if it turns out I like them. No affiliation with Madisound BTW except as an occasional customer- I just thought American builders might be interested if they hadn't noticed this. The drivers I have were purchased from IPL in the UK, but AFAIK I had the last pair from them.
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