'LGT' Construction Diary

[ShinOBIWAN]

Originally posted by KBK
Shin, I have those 4 drivers myself, and am saving them for another project. I'm using the 7's in a project right now. As for the 5"...Do they have a spyder with negative compression? IIRC, they come that way but it does look alarming, when you initially see it. I'm just looking for conformation on the negative position of the spyder thinge. Yours look like they have it as well, from the position of the cone.

As for the Weldbond, Guitar makers and Luthiers use it..due to one specific thing: It has the same mass and bonding characteristics of the wood itself, which is perfect for the laminate. The watered down weldbond makes for a deep and thorough bond point between the laminates..that has verly low 'changes' in density and internal reflection throughout the bond point, ie, it cuts down on multiple resonance issues within the material itself, that can be created via the laminante bonding point. It makes for a deep thorough bond point, with a non-hamonic resonance. You can see why it is a favorite of the luthiers, for repair or manufacturing. Basically, if one was to do a acellerometer based test for laminaite exitation and distortion, the weldbond laminate would likey show up to be the better configuration. Think about it.

A guitar has a tremendous amount of energy going through the body. The sound of that body is largely the major part of it's sound. Imagine if the sound of a given guitar was ruined in the process of repair. Weldbond..does NOT do this. Everytime it is used, the sound of the guitar is maintained and directly comparable to the original designs. This speaks volumes about it's use in speakers.

Thanks KBK, I didn't realise weldbond was used in that capacity and because of the properties you mention. Certainly worth remembering when doing lamination in the future if I don't go with the 4" thick and whittle a baffle out of that.

The AT drivers are the Rolls Royce of transducers, not the best performing but the sound is very refined and pleasing whilst the build quality and attention to detail is without peer IMO.

BTW I checked the spider issue you mentioned by looking directly down the side of the driver and through the basket windows to check the profile of the spider. It looks as though its in the normal 'at rest and centered' position to me. Have you had your drivers stored for a period of time in the upright position? Try flipping them over and leaving like that until you need them. If still concerned you know Per is always accessible.

[ShinOBIWAN]

Originally posted by tktran303
Ah, the secret's out Shin!

Now I know how you became so good with the cabinets!

I've always had great respect for car audio install guys- incredibly dedicated, take great pride in their rides, and perfectionists when it comes to their projects.

Way OT but have you seen Per Soda's Lime Beetle project?
http://www2.hemsida.net/bilstereo/index2.html

Click under Fabrication to check out the construction diary.

Woodwork, metalwork, fibreglassing, plastics... you name it, he does it:
http://www2.hemsida.net/bilstereo/li...6_Speakers.pdf

Leaves us home-speaker builders for dead.

About 7 or 8 years ago when a small group of us were at the height of our automotive audio phase we used to go to virtually all the local shows such as the ones at Don Valley, Donnington, Santa Pod Raceway etc.
Some of the installs at these places just made the eyes water, absolutely beautiful. It was a really big shot in the arm to try and emulate that stuff so we all went home with a head full of idea's and our standards vs. practical skill set in vast disproportion. We just kept trying, feeding off each others installs as they progressed and sharing idea's and experience. Nobody taught us anything so we all felt like we discovering all this for the first time - quite a buzz. Eventually we started to approach what we'd drooled over at these shows and afterwards took great pride in showing all this off to people genuinely interested. I always got a kick out of someone asking how we'd done this or that. Then after the show was done we'd go home and think of ways to make our installs better for next time.

I've now sort of grow out of all that, not really out of choice but because the rest of the gang I used to do all this with is now either married, have kids or moved away. But anyway, I moved my attention to DIY home audio just over 3 years ago and the car audio side of things prepared me well, at least in terms of cabinets and aesthetics.

With the links you've provided that is the type of work we aspired to and that got us so interested in the first place and whilst we never had results that good they did transition from plain old carpet covered sub box in the boot/trunk into something way above and beyond that. A hell of a lot of fun and I'll always have fond memories of those days.

[KBK]

Originally posted by ShinOBIWAN


Thanks KBK, I didn't realise weldbond was used in that capacity and because of the properties you mention. Certainly worth remembering when doing lamination in the future if I don't go with the 4" thick and whittle a baffle out of that.

The AT drivers are the Rolls Royce of transducers, not the best performing but the sound is very refined and pleasing whilst the build quality and attention to detail is without peer IMO.

BTW I checked the spider issue you mentioned by looking directly down the side of the driver and through the basket windows to check the profile of the spider. It looks as though its in the normal 'at rest and centered' position to me. Have you had your drivers stored for a period of time in the upright position? Try flipping them over and leaving like that until you need them. If still concerned you know Per is always accessible.

The've been in the boxes provided, sealed. But, on their sides. I opened them recently..and all 8 spyders and cone positions were screwed. Those drivers came to me a great expense as well...at the height of the Canadian dollar difference..which was $1.6 cdn to 1 US dollar. Plus, Per shipped them on my dime. And he did it 'overnight', which I did NOT ask for..... The shipping cost nearly made me puke. Over $700.

All told, the drivers cost me nearly $4k cdn. Now I'm ready to use them, and they are screwed. I need them --NOW-- for a show. They are at the center of about 10 years of work.

I'm not amused. I guess I'd better call him.

[ShinOBIWAN]

Originally posted by KBK


The've been in the boxes provided, sealed. But, on their sides. I opened them recently..and all 8 spyders and cone positions were screwed. Those drivers came to me a great expense as well...at the height of the Canadian dollar difference..which was $1.6 cdn to 1 US dollar. Plus, Per shipped them on my dime. And he did it 'overnight', which I did NOT ask for..... The shipping cost nearly made me puke. Over $700.

All told, the drivers cost me nearly $4k cdn. Now I'm ready to use them, and they are screwed. I need them --NOW-- for a show. They are at the center of about 10 years of work.

I'm not amused. I guess I'd better call him.

If there is a problem then sorry to hear about that.

Tomorrow I'll try and take a couple of photos so you can compare. It all looks normal to me but pictures will settle the matter quick sharp.

[tinitus]

I have wondered about how many drivers out there that are really centered properly, and how they do it anyway - but I am also told that when power is applied the voice coil will center itself automatically

[LaMa]

Originally posted by KBK
Shin, I have those 4 drivers myself, and am saving them for another project. I'm using the 7's in a project right now. As for the 5"...Do they have a spyder with negative compression? IIRC, they come that way but it does look alarming, when you initially see it. I'm just looking for conformation on the negative position of the spyder thinge. Yours look like they have it as well, from the position of the cone.

Can you elaborate on which 15H cquenze driver you are using? As my stock 15 H 52 06 13 SD drivers of <1 year old show the same negative spider (concave geometry when looked upon from the side).

[ShinOBIWAN]

I think you and KBK are confusing the non linear design of the spider with a fault. It is centered.

If you look carefully at the spider you'll see it has differing rib sizes, this can make it look as though its very slightly sagging but move the foam aside under the spider and you'll see it looks as if the spider is being pushed upwards. Its just the profile of the spider shape.

Its not common and the only other driver that I've owned with a similar design is the Scanspeak 18W sliced paper.

[LaMa]

Originally posted by ShinOBIWAN
I think you and KBK are confusing the non linear design of the spider with a fault. It is centered.

If you look carefully at the spider you'll see it has differing rib sizes, this can make it look as though its very slightly sagging but move the foam aside under the spider and you'll see it looks as if the spider is being pushed upwards. Its just the profile of the spider shape.

Its not common and the only other driver that I've owned with a similar design is the Scanspeak 18W sliced paper.

Sorry If I was not clear, I'm not saying that it is not standard or that the spider is sagging, I just want to illustrate that the drivers of KBK are most probably just fine and share the same design features as my drivers.

And yes I forgot to mention that it are just the ribs of the spider which are becoming smaller to the center.

Yes, the Scanspeaks show even more irregular spider shape, atleast the 15W8530 series.

[ShinOBIWAN]

Ah, sorry Lama, the mixup was at my end not yours.

[ssabripo]

geezus christ Shino, you never cease to amaze me!!