Hi Jim, I just ordered a pair of Alpair 10.3M and I am interested in this MLTL having seen your past designs. Could you explain how this alignment would differ in sound to the Pensil or the Frugel-horn XL?
They will be placed in a 30sq meter room with 3m ceilings, and will be right in or near corners (I can pull them out a bit). I am looking for a full sound with good bass, something I could not achieve with my Fostex cabs.
I also looked at GM's MLTL but would like to keep the height to under 48".
Thanks!
They will be placed in a 30sq meter room with 3m ceilings, and will be right in or near corners (I can pull them out a bit). I am looking for a full sound with good bass, something I could not achieve with my Fostex cabs.
I also looked at GM's MLTL but would like to keep the height to under 48".
Thanks!
I've never heard either of the alternative alignments.
I have built several MLTLs prototypes for many different designs/drivers. i like the tall and slim look of my MLTLs plus their sound is impressive.
The integration with your room will be key to achieving your goals--especially for good bass. Placement near the corners will give you additional acoustical gain but move them around to assess where they sound the best. You may have to add some baffle step compensation to balance their in-room sound.
Good luck with your project.
Jim
I have built several MLTLs prototypes for many different designs/drivers. i like the tall and slim look of my MLTLs plus their sound is impressive.
The integration with your room will be key to achieving your goals--especially for good bass. Placement near the corners will give you additional acoustical gain but move them around to assess where they sound the best. You may have to add some baffle step compensation to balance their in-room sound.
Good luck with your project.
Jim
That was my experience when I built similar MLTL using the Alpair 10p. My room only allows one placement option and the bass was not nearly as full and impressive as the simulations suggested it would be.
Thanks Jim for the reply. As mentioned I won't really be able to pull these far from the corners so I hope they're not too boomy.
Hi needtubes, what values did you wind up with? I will let the drivers break in for a few hundred hours before I judge the sound.
Bass is dominated by the room, but with the Pensils, one can pull out some damping for more bass.
dave
As P10 suggests:
"one can pull out some damping for more bass"
you can do the same with a MLTL.
The beauty of DIY is that you have control.
Jim
"one can pull out some damping for more bass"
you can do the same with a MLTL.
The beauty of DIY is that you have control.
Jim
Sorry I forgot to post this.
I created a pair of these speakers based on Jim's design.
This was my first speaker build!
I used a CNC router to machine the parts out of 12mm mdf.
I included a tongue and groove style so they fitted neatly together.
The final cuts are a consequence of the internal dimensions of Jim's plans.
I used dacron for the stuffing, packed tight in the top, looser in the bottom.
I used Alpair 10.2 because I had some laying around from a previous failed project.
I have some nice Jarrah to face the next pair with....might get to that someday.
I created a pair of these speakers based on Jim's design.
This was my first speaker build!
I used a CNC router to machine the parts out of 12mm mdf.
I included a tongue and groove style so they fitted neatly together.
The final cuts are a consequence of the internal dimensions of Jim's plans.
I used dacron for the stuffing, packed tight in the top, looser in the bottom.
I used Alpair 10.2 because I had some laying around from a previous failed project.
I have some nice Jarrah to face the next pair with....might get to that someday.
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How do they sound?
Have you put a stethoscope to the cabinet walls? 12mm mdf is like using 9mm quality ply and i'd think that might be a bit thin for such a large cabinet.
dave
Have you put a stethoscope to the cabinet walls? 12mm mdf is like using 9mm quality ply and i'd think that might be a bit thin for such a large cabinet.
dave
Understood...It was my first speaker build so I was lacking such knowledge.
Subjectively, they are awesome. Deep bass. I used a 25 watt Class d amp.
You do have to sit in front of them as the alpairs have a tendancy to beam the tops. I have them in my bedroom pointing at the bed from the opposite corners of the room. Nice.
JC,
I used Acousta Stuf material (polyfill) in my prototypes filling the top half of the enclosure as I mentioned in message #1 in this thread. See:
Acousta-Stuf Polyfill Speaker Cabinet Sound Damping Material 1 lb. Bag
As another alternative I also recommend bonded Dacron material in sheets as it is 0.75 pounds per cubic inch density which I assumed for the simulation for my design. See:
Bonded Dacron
You can likely locate similar material from other suppliers.
No other lining or fill below the top half of the box.
Jim
I used Acousta Stuf material (polyfill) in my prototypes filling the top half of the enclosure as I mentioned in message #1 in this thread. See:
Acousta-Stuf Polyfill Speaker Cabinet Sound Damping Material 1 lb. Bag
As another alternative I also recommend bonded Dacron material in sheets as it is 0.75 pounds per cubic inch density which I assumed for the simulation for my design. See:
Bonded Dacron
You can likely locate similar material from other suppliers.
No other lining or fill below the top half of the box.
Jim
Hi Jim, I have gone ahead and ordered wood for the project. I am trying to source a port tube over here in Spain and having difficulties.
I am able to get a 2" flared port, 5 3/4" long. Is this acceptable or will it change the alignment too much?
Thanks!
I am able to get a 2" flared port, 5 3/4" long. Is this acceptable or will it change the alignment too much?
Thanks!
Your 2" diameter flared tube is close so you could give it a try. Listen to the performance ascertain if you like the sound.
Other port tubes could be created from mailing tubes (typically cardboard) or pvc pipe. It don't have to be an expensive part from a supplier.
Other port tubes could be created from mailing tubes (typically cardboard) or pvc pipe. It don't have to be an expensive part from a supplier.
Rigid PVC plumbing pipe should also work fine.
For port diameter changes, the formula shared by P10 in the following link can help you with determining the length:
http://www.diyaudio.com/forums/full-range/282804-bass-reflex-port-shape.html#post4525003
For port diameter changes, the formula shared by P10 in the following link can help you with determining the length:
http://www.diyaudio.com/forums/full-range/282804-bass-reflex-port-shape.html#post4525003
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Thanks Jim and Zman. Using the calculator from Planet10's post I get an adjusted length of 3,83" for the 2"diameter.
Up to what point can the ports be changed without affecting the performance that Jim has achieved? For example is converting port length to baffle thickness or 2xbaffle thickness too drastic? It would allow for a very convenient and quite small hole.
I will look around a few plumbing supply shops in the city but I'm not sure they have much in the way of inches. The closest may be 50mm or 60mm.
Up to what point can the ports be changed without affecting the performance that Jim has achieved? For example is converting port length to baffle thickness or 2xbaffle thickness too drastic? It would allow for a very convenient and quite small hole.
I will look around a few plumbing supply shops in the city but I'm not sure they have much in the way of inches. The closest may be 50mm or 60mm.
I have finally built the first cabinet (still waiting for a port tube). I bought some 1cm thick ceiling insulation tiles. Would top, back and one side (in the top half only) be a good starting point?
Thanks!
Thanks!
I'm sorry but you will have to experiment with the ceiling tiles. I have never used them and can not give you much help on thickness and such.
I really suggest the polyfill or Dacron filling (pillow stuffing) as it is similar to what I use. You need a volume filler for typical MLTL operation vs. a surface damping material like those ceiling tiles. l
I really suggest the polyfill or Dacron filling (pillow stuffing) as it is similar to what I use. You need a volume filler for typical MLTL operation vs. a surface damping material like those ceiling tiles. l