GM's MLTL with 416-8B

[westend9]

I've kind of settled into a good listening schedule with the new boxes and have fiddled around with level matching and such. Also had a few visitors that confirmed we're on a good track with these. I even had my old buddy, Harry, in the room for a while. This is a cat that is over 90 and still recalls a lot of his speaker building days. To him, Sinatra was an upstart, funny stuff.

The woofers have seemed to break back in and other listeners have confirmed this. This is no surprise as I had them in storage for a couple of years. I think I can get the lower end a little "livlier" by removing some of the stuffing. I think it is a little too much for the application. I plan to remove about half the thickness and see if there is any change. I hope to get a little more reinforcement of the really low stuff by doing so. More of what's already present, I guess. Any suggestions appreciated on the stuffing.

Overall, the enclosures are very good, lower notes are reproduced substantially and the venerable 416b is allowed to shine. A board member suggested to get some measurement gear and that is on the schedule. I am weighing options on that.

[AltecLansingFan]

............. A board member suggested to get some measurement gear and that is on the schedule. I am weighing options on that.

You also can test the enclosures with your ears, with this CD http://amzn.to/ebCGnn
And of course, and that's very important; only testing in your listening room!!!

[westend9]

You also can test the enclosures with your ears, with this CD http://amzn.to/ebCGnn
And of course, and that's very important; only testing in your listening room!!!

Thanks, I'll get it coming my way.

[AltecLansingFan]

Thanks, I'll get it coming my way.

I think it's track 18, 19 and 20 (I'm not really sure) There you can hear all Hz from 10Hz and up. The best is that you can hear almost NO or less volume peaks in the frequency's.

I'm not an expert, but when I look to the enclosure, the briefcase vent looks not too big.
So I think when you have some problems with the LF, you can tune the vent, to make the vent deeper. I would start with a vent from around 6 cm deep (make a 4 cm. deep wood frame from plywood, and put that wood frame on the inside around the vent. In the test phase you can clamp it temporary with a clamp. (during the tests you can adjust the frame by cutting it smaller and find out what works best in your situation) Succes!

[GM]

Increasing vent length lowers F3, Fb, so for all but VLF special effects and some pipe organ symphonies, tuning lower would normally only be called for if the bass was too 'boomy' which can occur with corner loading. For more bass/mid-bass 'presence' [tonal balance] then, either a larger vent that raises F3, Fb and/or some baffle step compensation [BSC] is called for which is usually the case if the speakers are well away from any wall, corner boundaries. Of course, fiddling with these or any other fine tuning adjustments should only be done once installed in-room.

As for tuning by ear, it's better than nothing, but due to the way we perceive sound it's a crapshoot unless one has perfect pitch good enough to tune a piano and why I got in the habit of getting young women to help since men tend to do better down low while women do much better through the HF, so between the two, a decent balance can normally be struck and I'm guessing why I didn't have a clue what all SAF, WAF, etc. meant/implied when I got on-line.

GM

[airboss]

Very interesting project, and beautiful workmanship. I never did see a link to the original plan? Or maybe there isn't one.

Two thoughts, both incompletely informed perhaps. The result of idle midnight thinking.

Sealing openable joints: I've thought of using ordinary Crouse Hinds (or other manufacturer.) duct seal (sometimes called Elephant Poop amongst other things) My thinking has been to run it thorough my old hand crank pasta machine with the linguini blade installed after thickness rolling. The stuff is good forever in some pretty tough industrial settings but provision would need to be made with a "pry" lip attached to the removable piece. Or maybe a screw thread against a hard spot on the support cleats to break the seal. It's pretty sticky. Drivers can be attached to the baffle using these: http://www.mcmaster.com/#threaded-inserts/=bzcrce Drill the mounting holes so they don't go through the baffle, or (if they do) back them with a piece of 1/8th ply, glued in place with some of GM's magic poly glue. Actual leaks through the driver suspension (if bad enough) might require re-doping the surround. Weber speaker might sell some speaker dope; I dunno.

Second. I've heard some good things about R-13/R/18 for internal sonic resistance and have seen it settle over time to the bottom of the box. My thinking has been to loosely tack bird netting (the black UV resistant kind) over the bats to try and hold them in place. I've heard that packing the stuffing too tight will require a larger box for the same results as loose filling but it may be worth a try.

[westend9]

I think it's track 18, 19 and 20 (I'm not really sure) There you can hear all Hz from 10Hz and up. The best is that you can hear almost NO or less volume peaks in the frequency's.

I'm not an expert, but when I look to the enclosure, the briefcase vent looks not too big.
So I think when you have some problems with the LF, you can tune the vent, to make the vent deeper. I would start with a vent from around 6 cm deep (make a 4 cm. deep wood frame from plywood, and put that wood frame on the inside around the vent. In the test phase you can clamp it temporary with a clamp. (during the tests you can adjust the frame by cutting it smaller and find out what works best in your situation) Succes!

I was thinking forward to doing that very thing, temporarily adding a plywood vent extension. At this time, my ears tell me it is not necesary. I believe the designer hit the ball on the fat of the bat, it is going over the fence!

Increasing vent length lowers F3, Fb, so for all but VLF special effects and some pipe organ symphonies, tuning lower would normally only be called for if the bass was too 'boomy' which can occur with corner loading. For more bass/mid-bass 'presence' [tonal balance] then, either a larger vent that raises F3, Fb and/or some baffle step compensation [BSC] is called for which is usually the case if the speakers are well away from any wall, corner boundaries. Of course, fiddling with these or any other fine tuning adjustments should only be done once installed in-room.

As for tuning by ear, it's better than nothing, but due to the way we perceive sound it's a crapshoot unless one has perfect pitch good enough to tune a piano and why I got in the habit of getting young women to help since men tend to do better down low while women do much better through the HF, so between the two, a decent balance can normally be struck and I'm guessing why I didn't have a clue what all SAF, WAF, etc. meant/implied when I got on-line.

GM

My thoughts, too, GM, wait until I have everyting in situ. I'd sure like to have some measurement devices, at this point. I may get to a local place that stocks all of it and just plunk down the funds.

Very interesting project, and beautiful workmanship. I never did see a link to the original plan? Or maybe there isn't one.

Two thoughts, both incompletely informed perhaps. The result of idle midnight thinking.

Sealing openable joints: I've thought of using ordinary Crouse Hinds (or other manufacturer.) duct seal (sometimes called Elephant Poop amongst other things) My thinking has been to run it thorough my old hand crank pasta machine with the linguini blade installed after thickness rolling. The stuff is good forever in some pretty tough industrial settings but provision would need to be made with a "pry" lip attached to the removable piece. Or maybe a screw thread against a hard spot on the support cleats to break the seal. It's pretty sticky. Drivers can be attached to the baffle using these: http://www.mcmaster.com/#threaded-inserts/=bzcrce Drill the mounting holes so they don't go through the baffle, or (if they do) back them with a piece of 1/8th ply, glued in place with some of GM's magic poly glue. Actual leaks through the driver suspension (if bad enough) might require re-doping the surround. Weber speaker might sell some speaker dope; I dunno.

Second. I've heard some good things about R-13/R/18 for internal sonic resistance and have seen it settle over time to the bottom of the box. My thinking has been to loosely tack bird netting (the black UV resistant kind) over the bats to try and hold them in place. I've heard that packing the stuffing too tight will require a larger box for the same results as loose filling but it may be worth a try.

I've used duct seal to seal woofers to the cab, the Large Advebts had this as a stock sealant. I epoxied the T-nut fasteners into the inside of the baffle. I wouldn't think any air can travel through the filled T-nut. I passed through the heating/cooling section of a local lumber super-store, recently, and saw a woven filter containment material. It is close to what you have descibed, a loose weave. The purpose of the material is to hold spun filter elements when someone has to build a filter from scratch. I may remove some of the R-13 before the cabs are moved out of the shop and the additional netting sounds like a prudent idea.

I'm enjoying the heck out of these!