Hi Pete,
I think that AJ Horn is what I was thinking, I made a mistake refering to it as Hornresp. I did build these horns, the pic is one of the pair, one driver per horn. They were a bit of a challage to build so I think the Henkjan Horn would be a great choice as a first build. The Henkjan Horn looks like a great project, let us know how things turn out.
PJN
I think that AJ Horn is what I was thinking, I made a mistake refering to it as Hornresp. I did build these horns, the pic is one of the pair, one driver per horn. They were a bit of a challage to build so I think the Henkjan Horn would be a great choice as a first build. The Henkjan Horn looks like a great project, let us know how things turn out.
PJN
AJHorn is a commercial program (not expensive) of German origin, highly rated. you cannot enter input as detailed as in MJK's sheet (this mainly is a drawback when optimising stuffing) but it's results are good (only tends to exagerate the nulls). Actually Roland designed Conic with the aid of AJHorn.
Hornresp is a free program (author David McBean is here on the forum), you can download it from here: http://mywebsite.bigpond.com/dmcbean/
Hornresp is a free program (author David McBean is here on the forum), you can download it from here: http://mywebsite.bigpond.com/dmcbean/
Thanks Henkjan & PJN,
I will start with Henkjans Horn and maybe even try the BVR from Scottmoose - Sure I will let you know about the results !
Thanks a lot so far for all your support and comments !
Cheers
Peter
P.S. The Alpair10 suprises me everyday when I listen to it - played with moderate sound level it is a stunning performer ! And it plays all kinds of music - close to perfection for me !
I will start with Henkjans Horn and maybe even try the BVR from Scottmoose - Sure I will let you know about the results !
Thanks a lot so far for all your support and comments !
Cheers
Peter
P.S. The Alpair10 suprises me everyday when I listen to it - played with moderate sound level it is a stunning performer ! And it plays all kinds of music - close to perfection for me !
I finally received my pair of alpair 10FR and mounted them the last WE into the following speaker:
- Mass-Loaded Transmission Line (MLTL) load - took me time to find out the meaning of the abbreviation !, drawing inspiration from the plans published earlier in this and other threads
- slightly larger volume than what I've read : external dimensions 120cm x 20cm x 20cm (higth x depth x width) using 1,9 cm thick massive wood ; I was a bit lazy and since I found found convenient 120x20cm pannels at the shop, I just decided to use these to limit cuting and woodwork
- speaker centre at approx. 30cm from the top and on the back pannel, just opposite, I've put 20 cm x 30 cm of acoustic foam with a deep profile
- port is 6cm in diameter (no tubing, just the 1,9 cm depth given by the thickness of the wood), mounted in the bottom of the speaker, radiating to the floor; speakers are mounted on 3 cm high spikes so that the bottom pannel and the floor itself constitute the prolongation and airload of the vent. The spikes can be changed (or replaced by lower rubber cones) and thus distance to the floor and bass radiation is adjustable to my own environment; the theoretical advantage of floor radiation that I see is that I have no parasitic sound radiation compared to a front-mounted vent (bearing in mind the speaker is used full range...).
I knew from experience with the FE103S and the "petite audiophile" that this kind of drivers are quite forgiving and work well also in larger loads than theoretically required, but I don't know how far I've deviated now from the MLTL model...I had never heard of MLTL loads until now, another reason why I wanted to experiment with this type of enclosure.
The drivers were mounted directly from their box onto the enclosure, and will undergo the "burn in" process in situ. Pending the completion of this process, the sound is - as expected and as another poster at least has noticed - a little on the bright side. I mounted after an hour a serial filter composed of a parallel combination of 3,3mH/2,2R/2,2uF just to continue audition tests in the meantime (the values were determined empirically and without proper calculation but it is OK
)
Conclusion: this "thingie" has a huge potential. Believe it or not, even without breaking in, the bass goes subjectively as deep as my main system's 400liter enclosures each loading a pair of 15inch woofers... I post provisional listening tests in the other thread entitled "focus listening experience".
Congrats to those who have come up with the MLTL principle!
- Mass-Loaded Transmission Line (MLTL) load - took me time to find out the meaning of the abbreviation !, drawing inspiration from the plans published earlier in this and other threads
- slightly larger volume than what I've read : external dimensions 120cm x 20cm x 20cm (higth x depth x width) using 1,9 cm thick massive wood ; I was a bit lazy and since I found found convenient 120x20cm pannels at the shop, I just decided to use these to limit cuting and woodwork
- speaker centre at approx. 30cm from the top and on the back pannel, just opposite, I've put 20 cm x 30 cm of acoustic foam with a deep profile
- port is 6cm in diameter (no tubing, just the 1,9 cm depth given by the thickness of the wood), mounted in the bottom of the speaker, radiating to the floor; speakers are mounted on 3 cm high spikes so that the bottom pannel and the floor itself constitute the prolongation and airload of the vent. The spikes can be changed (or replaced by lower rubber cones) and thus distance to the floor and bass radiation is adjustable to my own environment; the theoretical advantage of floor radiation that I see is that I have no parasitic sound radiation compared to a front-mounted vent (bearing in mind the speaker is used full range...).
I knew from experience with the FE103S and the "petite audiophile" that this kind of drivers are quite forgiving and work well also in larger loads than theoretically required, but I don't know how far I've deviated now from the MLTL model...I had never heard of MLTL loads until now, another reason why I wanted to experiment with this type of enclosure.
The drivers were mounted directly from their box onto the enclosure, and will undergo the "burn in" process in situ. Pending the completion of this process, the sound is - as expected and as another poster at least has noticed - a little on the bright side. I mounted after an hour a serial filter composed of a parallel combination of 3,3mH/2,2R/2,2uF just to continue audition tests in the meantime (the values were determined empirically and without proper calculation but it is OK
)Conclusion: this "thingie" has a huge potential. Believe it or not, even without breaking in, the bass goes subjectively as deep as my main system's 400liter enclosures each loading a pair of 15inch woofers... I post provisional listening tests in the other thread entitled "focus listening experience".
Congrats to those who have come up with the MLTL principle!
Hi everybody,
I'm building my speakers, based on the Alpair 10 FR, following the great ML-TL project by Jim Griffin. I have some questions about the damping material. Which one is the most indicated? I'm looking for something that can be just glued on the panels without the risk of "collapse" due to vibrations. In terms of "ease of use" I think felt should be the best option but I don't know if there are clearly better (in terms of efficacy) alternatives. Another issue is about the thickness of the material, I'm not able to translate with confidence this parameter: "stuffing density is 0.5 pound per cubic foot"...
Is this one: http://www.audiophonics.fr/mousse-damortissement-laine-pour-enceintes-p-1366.html similar to Acousta Stuff (used by Mr. Jim Griffin)? Someone see something fine for this project at the following page?: http://www.audiophonics.fr/accessoires-amortissants-c-37_197.html
At last, do I have to cover (from below the driver to the top of the box) all the internal faces or just the top, the rear and the two side panels, leaving without damping the face with the driver?
Sorry for such a meticulous questions but if I understand correctly the damping is a crucial component in a ML-TL enclosure...
Thanks a lot and regards,
Christian
I'm building my speakers, based on the Alpair 10 FR, following the great ML-TL project by Jim Griffin. I have some questions about the damping material. Which one is the most indicated? I'm looking for something that can be just glued on the panels without the risk of "collapse" due to vibrations. In terms of "ease of use" I think felt should be the best option but I don't know if there are clearly better (in terms of efficacy) alternatives. Another issue is about the thickness of the material, I'm not able to translate with confidence this parameter: "stuffing density is 0.5 pound per cubic foot"...
Is this one: http://www.audiophonics.fr/mousse-damortissement-laine-pour-enceintes-p-1366.html similar to Acousta Stuff (used by Mr. Jim Griffin)? Someone see something fine for this project at the following page?: http://www.audiophonics.fr/accessoires-amortissants-c-37_197.html
At last, do I have to cover (from below the driver to the top of the box) all the internal faces or just the top, the rear and the two side panels, leaving without damping the face with the driver?
Sorry for such a meticulous questions but if I understand correctly the damping is a crucial component in a ML-TL enclosure...
Thanks a lot and regards,
Christian
Hi Ilwooz,
I've used this type,
http://www.audiophonics.fr/mousse-damortissement-40mm-pour-enceintes-p-1637.html
in fact a slightly thicker version, about 60mm or so which was available from a local store.
I used one piece only, mounted on the back panel between the top and the brace (opposite to the speaker), fixed with some Pattex strong glue sold in cartridge; in my case, I feel it was enough but I confess I did not experiment with more pieces of foam in other places.
Cheers.
Chris.
I've used this type,
http://www.audiophonics.fr/mousse-damortissement-40mm-pour-enceintes-p-1637.html
in fact a slightly thicker version, about 60mm or so which was available from a local store.
I used one piece only, mounted on the back panel between the top and the brace (opposite to the speaker), fixed with some Pattex strong glue sold in cartridge; in my case, I feel it was enough but I confess I did not experiment with more pieces of foam in other places.
Cheers.
Chris.
Hi elac310,
thanks a lot for your response. So you glued the foam only on the back panel. I saw (this is what I understood) that in the ML-TL 48 project for the Jordan JX92S driver the damping material cover all the internal faces of the cabinet from the top to below the driver. Hence in the case of the Alpair 10 do you think is too much? On the audiophonics page you kindly linked is reported the parameter of 20 kg/m3; converting pound unit in kg I see a result, compared to the parameter "0.5 pound per cubic foot", that have no sense for me (you see, I'm ignorant a little...). So many questions for the simple reason that is very difficult to try and experiment with different amount of material, building a cabinet with non-professional tools. And once the box is closed...
Thanks a go-go and bye,
Christian
thanks a lot for your response. So you glued the foam only on the back panel. I saw (this is what I understood) that in the ML-TL 48 project for the Jordan JX92S driver the damping material cover all the internal faces of the cabinet from the top to below the driver. Hence in the case of the Alpair 10 do you think is too much? On the audiophonics page you kindly linked is reported the parameter of 20 kg/m3; converting pound unit in kg I see a result, compared to the parameter "0.5 pound per cubic foot", that have no sense for me (you see, I'm ignorant a little...). So many questions for the simple reason that is very difficult to try and experiment with different amount of material, building a cabinet with non-professional tools. And once the box is closed...
Thanks a go-go and bye,
Christian
I built the Jordan MLTL-48. Greg Monfort, the designer of the cabinet, suggested to cover with damping material (fiberglass) only two walls (see the thread dedicated to the Jordan MLTL) and add or remove more damping to proper taste.
I preferred to not use the fiberglass because this material has been questioned to produce possible health problem due to the fiberglass dust that can be breath during cutting and installation.
I used the damping material of Monacor that I could easily find in my town, but I have not experience with different product
see here
Renato
ilwooz said:
Greets!
Yes, the damping is crucial to any ~full range driver speaker and why any damping suggestion should be considered just a starting point since we all hear the same, yet not so much. FWIW, many builders have PM'd me to say they used only a fraction of what I suggested on the various MLTL designs, so I quit suggesting amounts that made the smoothest/flattest sim. Note too that MJK's software is based solely on loose polyfil evenly distributed along 'X' distance from the top and loses whatever accuracy the sim has once you move away from this material, procedure.
For instance, I prefer the traditional 1" thick 'ridgid' acoustic fiberglass insulation popular with many manufacturers until its health issues when used in mass quantities became common knowledge. Its damping factor is considerably higher than polyfil, hence my default suggestion of lining just one each of any parallel walls, so normally this would be the top, one side and back down to at least just below the driver as a baseline for experimentation. To stuff a MLTL with it would turn it into an aperiodic alignment (~sealed cab response). Note that maximum damping benefit is found at the closed end of the pipe, so from the top down to above the driver is where I put it when I need to add more.
Wearing a simple dust mask and handled with gloves, this is ample protection for even the amount of dust generated to cut/move around enough for my two ~20 ft^3 cabs if you run a vacuum cleaner nearby to suck up any 'hanging' around. Once in the cab, it's not enough of a health issue unless any vent opening is large enough to allow pets or toddlers to climb in. For the paranoid among us, a cloth grill stretched tightly over the vent contains it.
Any of the polyester or open cell foam sheeting can be used to line walls though and lined as I suggested in an offset driver MLTL I doubt that many folks will want more unless the sheeting used turns out to have very low density.
Anyway, "stuffing density is 0.5 pound per cubic foot" simply means that you multiply the cab's net volume (Vb) in ft^3 times 0.5, then measure out that much stuffing material on a scale.
GM
Hi,
Thanks a lot Greg and Renato for your very kind response.
I think now I understand how to experiment with the damping material for my speakers. Greg, your explanation is very exhaustive and precious!
Following your suggestions I'll start with cover only the top and the back (from the top down to below the driver), then one side panel too, then...
Here in Italy we are very frightened about the fiberglass, I think I'll go with open cell foam sheeting or a damping material like the Monacor linked by Renato (looks analogue to this one: http://www.audiophonics.fr/mousse-damortissement-laine-pour-enceintes-p-1366.html).
I only have to find the most convenient way to testing different amount of stuffing without closing the box (I mean with all the panels glued, just leaving one removable). I also suppose is better to burn-in the drivers (maybe on the floor, while assembling the cabinet) before doing the tests, just to have a more realistic and reliable response, otherwise I think I could run into misunderstandings since the sound evolves over time...
Thanks again guys and have a nice day,
Christian
Thanks a lot Greg and Renato for your very kind response.
I think now I understand how to experiment with the damping material for my speakers. Greg, your explanation is very exhaustive and precious!
Following your suggestions I'll start with cover only the top and the back (from the top down to below the driver), then one side panel too, then...
Here in Italy we are very frightened about the fiberglass, I think I'll go with open cell foam sheeting or a damping material like the Monacor linked by Renato (looks analogue to this one: http://www.audiophonics.fr/mousse-damortissement-laine-pour-enceintes-p-1366.html).
I only have to find the most convenient way to testing different amount of stuffing without closing the box (I mean with all the panels glued, just leaving one removable). I also suppose is better to burn-in the drivers (maybe on the floor, while assembling the cabinet) before doing the tests, just to have a more realistic and reliable response, otherwise I think I could run into misunderstandings since the sound evolves over time...
Renato, You simply glued the damping material?
Thanks again guys and have a nice day,
Christian
You're welcome!
FWIW, since I'm a believer in mass loading lightweight cabs, especially tower designs, I do a two piece top where one is recessed and mounted to rabbiting that's easily gasketed with neoprene and add a massive, decorative marble or similar one to cover it up. For budget builds, a plain wood/whatever one with a heavy planter perched on top works of course and has some WAF if that's an issue.
GM
FWIW, since I'm a believer in mass loading lightweight cabs, especially tower designs, I do a two piece top where one is recessed and mounted to rabbiting that's easily gasketed with neoprene and add a massive, decorative marble or similar one to cover it up. For budget builds, a plain wood/whatever one with a heavy planter perched on top works of course and has some WAF if that's an issue.
GM
Hi,
it is funny, I have to look to the English dictionary to speak with a guy of my country (I hope found the correct words):
I just fixed each sheet with a couple of upholsterer staplers. It should be a temporary fix, but it seems to work. Even if it is almost one here I am listening to my Jordan I still have to paint them.
Renato
Hi Jim and all friends,
Recently just finish the ML-TL design, but i replace the FR with ALPAIR 10 BASS and add ALPAIR 5 on top of it with separate cylinrical enclosure.
My front baffle are 1" solid mango wood, with 3/4" plywood on others.
I didnt make any adjustment on the volume although using diff driver and have approx 2litres of enclosure for the Alp5 (approx 9cm diam with 8cm deep).
The last one would be a rectangular port with 2.5cm height, 16cm width and 10cm deep, i notice this one twice as the original port.
Now what im experiencing is lack of bass, didnt go low enough and no punch.
I didnt fill with anything yet, since just finish for 2days.
Any recommendations ?
Cheers
Henry
Recently just finish the ML-TL design, but i replace the FR with ALPAIR 10 BASS and add ALPAIR 5 on top of it with separate cylinrical enclosure.
My front baffle are 1" solid mango wood, with 3/4" plywood on others.
I didnt make any adjustment on the volume although using diff driver and have approx 2litres of enclosure for the Alp5 (approx 9cm diam with 8cm deep).
The last one would be a rectangular port with 2.5cm height, 16cm width and 10cm deep, i notice this one twice as the original port.
Now what im experiencing is lack of bass, didnt go low enough and no punch.
I didnt fill with anything yet, since just finish for 2days.
Any recommendations ?
Cheers
Henry
The crossover was recommended by Tony Gee,
series crossover
3,9mH + 40uf
with notch filter for the 10; 10uf + 10ohm, and 3ohm resistor on the 5.
Which provide a good balance, but lack of bass.
Right now im experimenting with
2,0mH + multiple caps (15+4.7+3.9+3.9 uf ), since thats the only one in variation to the 1pc of 40uf.
others are still the same.
Cheers
series crossover
3,9mH + 40uf
with notch filter for the 10; 10uf + 10ohm, and 3ohm resistor on the 5.
Which provide a good balance, but lack of bass.
Right now im experimenting with
2,0mH + multiple caps (15+4.7+3.9+3.9 uf )
, since thats the only one in variation to the 1pc of 40uf.others are still the same.
Cheers
Henry,
Based on your inputs you have:
1. Reduced the Alpair 10 enclosure size about 10% to allow volume for the A6 vs. the volume of my A10 prototypes
2. Nearly doubled the port area vs. my prototypes
3. No stuffing in the box
I modelled those changes in the Martin King worksheet and I get a low end response that has a F3 that is about 10 Hz (mid 40's vs. mid 30's Hz) above my results for a proper sized and stuffed box with correct port size. The lack of stuffing causes a peak in the response on the low end so the bass may sound imbalanced vs. flat and balanced with the mid frequencies. No stuffing will also create uneven performance in the mid-bass area as well. Thus I am not too shocked that you have reduced bass.
In order of impact for your enclosures I would reduce the port area and add stuffing to achieve a better respose. More cross-sectional area (increase your box size by 10%) would help but the easier changes to make are the port sizing and stuffing.
Jim
Based on your inputs you have:
1. Reduced the Alpair 10 enclosure size about 10% to allow volume for the A6 vs. the volume of my A10 prototypes
2. Nearly doubled the port area vs. my prototypes
3. No stuffing in the box
I modelled those changes in the Martin King worksheet and I get a low end response that has a F3 that is about 10 Hz (mid 40's vs. mid 30's Hz) above my results for a proper sized and stuffed box with correct port size. The lack of stuffing causes a peak in the response on the low end so the bass may sound imbalanced vs. flat and balanced with the mid frequencies. No stuffing will also create uneven performance in the mid-bass area as well. Thus I am not too shocked that you have reduced bass.
In order of impact for your enclosures I would reduce the port area and add stuffing to achieve a better respose. More cross-sectional area (increase your box size by 10%) would help but the easier changes to make are the port sizing and stuffing.
Jim
Posting your MJK model in text form
Hello Jim,
I have recently subscribed to MJK's new worksheets and have input your enclosure dimensions. I'd like to send a text version to you as I'm curious if it's correct. Have you joined Martin's yahoo group, and if so would you be willing to post a text version of the model? I think many on the group could benefit from such an effort.
Best Regards, Mark V.
Hello Jim,
I have recently subscribed to MJK's new worksheets and have input your enclosure dimensions. I'd like to send a text version to you as I'm curious if it's correct. Have you joined Martin's yahoo group, and if so would you be willing to post a text version of the model? I think many on the group could benefit from such an effort.
Best Regards, Mark V.
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