hjames
02-23-2011, 06:02 AM
I got a pair of L100T speakers a few weeks back. Even tho I had a pair of them 2 years ago, and sold those off to a list member,
the price for these was exceptional, they had already been refoamed, and they are nearly perfect,
except for a ding on the top right corner of 1 of them. So, I couldn't resist!!
50114
The smaller box next to it is our B380 sub ...
Of course they have the original L10T crossover, not the advance T3 version that smooths the top-end ...
I had my previous L100T crossovers reworked by a forum member - I like the improvement and will probably
have these new ones upgraded. His thread here -
http://www.audioheritage.org/vbulletin/showthread.php?7812-L100T-vs-L100T3
They sound good as is. I'm currently using them as surrounds in my media room.
Its a small room so they are pretty much flush against the wall, and am troubled by the rear ports.
So - my first thought is to "move" the ports to the front. I did this with a pair of L60Ts a while back,
matched the placement of the front port with a pair of L20Ts, and while I was never a fan of the L60T, it didn't make the sound any worse.
So - any thoughts, comments, experiences on tweaking L100Ts ...
I lifted this quote from another thread on L100T refoaming that drifted a bit.
It fits this thread, although I have no need (or the skills) to create new cabinets for mine ...
Vent location is not critical, as long as it does not open right at the back of the woofer cone.
That can cause noises. (Upper ranges of the woofer back-wave that normally get absorbed by the fiberglass stuffing.)
I prefer front ports myself, so the rear ports on my L100T's are sort of a pain to deal with.
(It means that you cannot position close to a wall, have to have some space.)
On mine, one of the cardboard tubes was all crinkled up on the inside, so I bought some 4" flared ports off the 'bay. They were too short, so I trimmed them to be half as long as they need to be, and used two per box. Some PVC cement holds them together. I read somewhere (some link Zilch posted somewhere...) that the distortion caused by a port goes down with the flared port, and that both ends must be flared for the lowest distortion. Even lower distortion is possible if the inside end of the port is mounted on a baffle. So I found a way to put one in the bottom of the box, sort of as a cross-brace going side to side about midway between the front and the back. It's about 14" X 14" made of 3/4" mdf. I figured that it would have to be made in two pieces to get it in the finished box, so I cut 2 square pieces, then cut them in half. After cutting them in half I glued the center only back together so that I could cut a round hole for the port. Since only the center was glued, I ended up with a round piece and two rectangles with a half circle missing on one side. One of these went in the bottom and was glued tight. Meanwhile, the rear port hole was too small for the flared ports, so I had to cut a plug to tap into the hole to give me a center for my Jasper jig to turn on. I then cut the larger size hole in the rear, and mounted the flared port, half from the back, half from inside, with the PVC cement in the middle. Lastly the second half of the inner baffle went in and was glued down over the inside flared end.
I think they sound a little tighter in the lowest registers now, with all the work, they'd better!
So anyway, this has been a long way of saying, if you do redo the boxes, put the port on the front, and use flared ends, inside and out, and think about putting a brace in that forms a baffle for the inside end of the port tube. (Plus others to tie the front to the back as well.)
Oh, and put the mid and tweeter on one box to the left, and one to the right. (Mirror image.)
The front baffle dimensions are a really good starting point for a new box, because if you change them that may upset the frequency response of the speaker. At least in theory the crossover is designed with those dimensions in mind. Moving the mid and tweeter from the left side to the right wont matter, as long as the dimensions from each side and from the top and bottom of each driver are the same as the other one. If you really want to change the baffle dimensions, I'd build one box and compare the sound to the original box before building the second...
the price for these was exceptional, they had already been refoamed, and they are nearly perfect,
except for a ding on the top right corner of 1 of them. So, I couldn't resist!!
50114
The smaller box next to it is our B380 sub ...
Of course they have the original L10T crossover, not the advance T3 version that smooths the top-end ...
I had my previous L100T crossovers reworked by a forum member - I like the improvement and will probably
have these new ones upgraded. His thread here -
http://www.audioheritage.org/vbulletin/showthread.php?7812-L100T-vs-L100T3
They sound good as is. I'm currently using them as surrounds in my media room.
Its a small room so they are pretty much flush against the wall, and am troubled by the rear ports.
So - my first thought is to "move" the ports to the front. I did this with a pair of L60Ts a while back,
matched the placement of the front port with a pair of L20Ts, and while I was never a fan of the L60T, it didn't make the sound any worse.
So - any thoughts, comments, experiences on tweaking L100Ts ...
I lifted this quote from another thread on L100T refoaming that drifted a bit.
It fits this thread, although I have no need (or the skills) to create new cabinets for mine ...
Vent location is not critical, as long as it does not open right at the back of the woofer cone.
That can cause noises. (Upper ranges of the woofer back-wave that normally get absorbed by the fiberglass stuffing.)
I prefer front ports myself, so the rear ports on my L100T's are sort of a pain to deal with.
(It means that you cannot position close to a wall, have to have some space.)
On mine, one of the cardboard tubes was all crinkled up on the inside, so I bought some 4" flared ports off the 'bay. They were too short, so I trimmed them to be half as long as they need to be, and used two per box. Some PVC cement holds them together. I read somewhere (some link Zilch posted somewhere...) that the distortion caused by a port goes down with the flared port, and that both ends must be flared for the lowest distortion. Even lower distortion is possible if the inside end of the port is mounted on a baffle. So I found a way to put one in the bottom of the box, sort of as a cross-brace going side to side about midway between the front and the back. It's about 14" X 14" made of 3/4" mdf. I figured that it would have to be made in two pieces to get it in the finished box, so I cut 2 square pieces, then cut them in half. After cutting them in half I glued the center only back together so that I could cut a round hole for the port. Since only the center was glued, I ended up with a round piece and two rectangles with a half circle missing on one side. One of these went in the bottom and was glued tight. Meanwhile, the rear port hole was too small for the flared ports, so I had to cut a plug to tap into the hole to give me a center for my Jasper jig to turn on. I then cut the larger size hole in the rear, and mounted the flared port, half from the back, half from inside, with the PVC cement in the middle. Lastly the second half of the inner baffle went in and was glued down over the inside flared end.
I think they sound a little tighter in the lowest registers now, with all the work, they'd better!
So anyway, this has been a long way of saying, if you do redo the boxes, put the port on the front, and use flared ends, inside and out, and think about putting a brace in that forms a baffle for the inside end of the port tube. (Plus others to tie the front to the back as well.)
Oh, and put the mid and tweeter on one box to the left, and one to the right. (Mirror image.)
The front baffle dimensions are a really good starting point for a new box, because if you change them that may upset the frequency response of the speaker. At least in theory the crossover is designed with those dimensions in mind. Moving the mid and tweeter from the left side to the right wont matter, as long as the dimensions from each side and from the top and bottom of each driver are the same as the other one. If you really want to change the baffle dimensions, I'd build one box and compare the sound to the original box before building the second...