CraigsAudio wrote:I got one more evening of work done on the T39's. They are actually a little further along then what the pics show. The PL is cleaned up, holes filled, edges rounded over, and the cabs are sanded. Either tomorrow or Saturday I will start with flat black latex followed by two coats of Duratex.
el_ingeniero wrote:I notice you're doing something a bit different than my plans with the top ... can you talk about that?
The tops are different then the standard build because the cabs are slims. I took the pics before I glued wood around so that there is a lip to attach the access panel to, I will take a few more pics to show the rest of the details. This pair of T39's measure 13" wide OD and are built with 12" panels. The plans do specify the tops the way I have built them for the extreme slim version. These are the narrowest size for a 10" woofer. I need one narrow pair for small gigs where my family will be coming along. The space available in the back of out minivan will not allow for a much wider cab when my wife and 3 kids are in the car. The rest of my T39's will be 24" Lab12 loaded.
The choices that I made in selecting cabs let the system range from a small with family in minivan size up to large outdoor event size.
I have the plans for the T-39, I could tell that they are the slims. My plans show the top panels overhanging the baffle and back of the speaker chamber by an inch and a half or so. I was figuring you'd make the top cover all one piece or something.
I double checked my plans and the sketchup model. It looks just like what I built. I did get the latest copy of the T39 plans about 2 months ago since my almost 2 year old CD does not have the updates for the Lab drivers. Maybe there has been a revision? If I had left 1 1/2" overhang and then added a wood lip to that the driver opening would be rather small. Even if the driver fit I doubt that my hands would fit in there to screw down the driver. Are you sure that what you are seeing as an overhang is not really the wood lip that the top mounts onto?
I agree, the T39 is the ideal horn loaded sub. The balance between size, output, and extension is perfect. Anything larger that has more extension is a waste for me both in terms of pack space and ease of handling. I may even change my plan a little and go with 4 BP102 slims and 4 24"Lab 12 loaded for symmetry. After that just like you stated come the 30" ones, at that point pack space becomes irrelevant. If I ever got to that size I would get an enclosed trailer.
There's an argument for building 2X BP102 slims, 2X 24" Lab12 and 4X 30" Lab12.
The 6 extra inches going from 24" to 30" should be good for roughly 3 more DB, which means you can increase your audience size 40% or so and still bring just 1 pair of subs.
Stack all 6 Lab12 loaded cabs, and you hardly need a V-Plate.
el_ingeniero wrote:But if I ever build more, I'll go 30" wide. If I need to bring that much, pack size becomes a secondary consideration.
You know, that is a good point. You got me thinking that if (when) I build my next pair of T39s I am going to build them as wide as possible, but still narrow enough to fit through doors. That way I got 20" wide for regular stuff, the big boys for bigger shows and both for outdoors.
Omni 10
Omni 10.5
OmniTop 12 x 4
Wedgehorn 8 x 3
XF212
T39 @ 18" x 2
T39 @ 20" x 2
T39 @ 28" x 2
Jack 110 x 5
Jack Lite 12
XF210
XF210 (Slant only, no crossfire)
These were fun and very easy to build. They have been checked for leaks and are ready to go. So far they have only been played at low levels in my house (sleeping kids). I can't wait to get them in a larger space and see what they can do. My next project will be a pair of 24" wide T39's. I already have all the parts and 2 Lab12's. I am going to make them 20" deep like a few others have done so that an access panel can be made instead of using the piano hinge.
These were fun and very easy to build. They have been checked for leaks and are ready to go. So far they have only been played at low levels in my house (sleeping kids). I can't wait to get them in a larger space and see what they can do. My next project will be a pair of 24" wide T39's. I already have all the parts and 2 Lab12's. I am going to make them 20" deep like a few others have done so that an access panel can be made instead of using the piano hinge.
Looks really good. I doubt mine will be even close to that nice.
Looks like I will have more time after I get married to work on them. One thing I intend to do is putting the jack dish at the bottom of the cabinet to make for less running back and forth when I daisy chain them one 1 amp channel.
I'll also put put a hinged access cover over them that snaps shut to keep out some of the grime and filth from winter sidewalks.
I'll figure out a way of opening a space just large enough for 2 10G cables so I can close the access cover with the cables plugged in.
el_ingeniero wrote:I'll also put put a hinged access cover over them that snaps shut to keep out some of the grime and filth from winter sidewalks.
That's what the VOLUME control is for, turn it up and BLOW them out
I'll figure out a way of opening a space just large enough for 2 10G cables so I can close the access cover with the cables plugged in.
Other jack locations that I was considering were low on the back or in the horn mouth. If a pair of each of these were installed no matter how the subs are placed the cables could always be run such that they are out of sight/out of mind, the audience would never see the jacks and the wire could be run out of the way of stray feet.
Tonight I got my first chance to give the T39's a tryout. I tested both of them in my workshop. It is small measuring 16' X 16'. Soon I will move my shop out to the garage but before that can happen I have to poor a slab. Both subs tested fine and worked well together. Because off tools, scrap..... I could not place them properly and I am sure that there were cancellations. Once they were verified for proper operation I brought one T39 in my living room. My living room is about 25' X 13' and I corner loaded the sub. A BBE DS24 was used for the processing. The BBE fed a Crown 602 for the sub and the an Adcom amp for my ADS towers. This time the output was much better with the single sub dwarfing the output of the pair in my workshop by a large margin. Proper placement makes a big difference. Never assume that just because you have excellent subs that the sound will be good. Direct radiators also benefit greatly with proper placement.
The sound was very clean. Gone was the usual distortion which causes that struggling woofer sound that I loath in pro gear. What remained was clean natural sounding bass that filled the room. It made my ADS's sound puny and inadequate. Even though the ADS's are very good I prefer a large sound stage. In the past I has a pair of Acoustat electrostatic loudspeakers that had an incredible sound stage. The DR's that I built also have that same room filling quality to them. Anyway after testing the sub it is apparent that I need new mains that will keep up, and my wife agrees, that means another build I have one more pair of subs (Lab12) that I need to make cabs for. After that TLAH's and a Table Tuba will be next.
One of my T39's has developed a fatal flaw....... my wife will not let it leave the living room Looks like I may have to bump up the priority level of the table tuba build so that I can get it back
CraigsAudio wrote:One of my T39's has developed a fatal flaw....... my wife will not let it leave the living room Looks like I may have to bump up the priority level of the table tuba build so that I can get it back
You lucky bastard . If only my wife was eagerly awaiting my builds, I might actually get some done .
(who am I kidding, I'd still be putting some of it off)
I have one more pair of subs (Lab12) that I need to make cabs for. After that TLAH's and a Table Tuba will be next.
Looks like I may have to bump up the priority level of the table tuba build so that I can get it back 
. If only my wife was eagerly awaiting my builds, I might actually get some done 
.