Introducing: The Pit Vipers (Ooh Yeah!!!)

[Serenitynow]

I think I am going to try to wrangle in some of the low end hype by adding extra insulation.

How does adding extra insulation alter the low end of these ? Extension, punch, volume, etc ?
How much extra insulation is required and where should it be placed in the cabinet ?

[sonic_tooth]

I just received my parts order to build a pair of these last week. I think I am going to try to wrangle in some of the low end hype by adding extra insulation. I'm not sure what the trade off is by doing so. I'm going to be using these speakers as a secondary listening reference (I use Bagby RS180s for my primary/nearfields) for mixing and mastering work so I think a little bit less "party" might be better for my build. I will still do quite a bit of listening just for fun as well so I'm a bit torn. I guess its easy enough to adjust after the fact. Looking forward to hearing these!!!

[9sheng]

Hey, @Wolf​, thank you for your reply first. When I checked the manufacturer's capacitance specifications yesterday, I happened to think that using 3.3uf+47uf is a feasible solution. I spent some time on the resistance and found 1 ohm, 4.7 ohm and 10 ohm cement resistors of 30W. I think this power should be enough.



Now I attach the pictures of accessories used for your reference​






These are the pictures of the merchants. The parts have not arrived on my desktop

[Wolf]

Just parallel a 3uF with the 47uF to get 50uF, easy peasy.

Paul means in excess output levels, like 100dB or more. I think what you propose can work fine. If not, then use a series parallel arrangement of the 4.7 ohm with 4 resistors.

Later,
Wolf

[9sheng]

@Paul Carmody​, when I was selecting the divider parts, I found that there was no local (C2) 50uf capacitor, only 47uf, 56u and 68u for the time being. I want to say whether these three specifications are all OK? C2 If the capacitance of this capacitor slightly deviates, will it affect the whole?

At the end of your article, I said that please use a higher power resistor for a long time of high-power use. I found that only medium and high resistance circuits were used. The problem I encountered was that I could only find 30W resistance of 1 ohm and 10 ohm, but only 10W resistance of 4.7 ohm. My problem is that the power of the tweeter should be less than that of the midrange speaker. So I want to use a 30W resistor in the midrange circuit and a 10W resistor in the tweeter circuit. Can this scheme also meet the requirements of 10-20 hours of continuous playback.

thank you！​

[djg]

Now revealed, the real reason I did my nostalgia build of JR's 3 way. These Pit Vipers reminded me of the JBL L100Ts in my past. I have no use and no room for the Pit Vipers and the walnut veneer to make them look like the JBLs would be pricey. But I did consider the project.

The little monkey coffins provided a reasonably sized and priced trip down memory lane of even older vintage.

I hope to see someone's completed pair of these soon.

[Serenitynow]

I'm still here.
I got all the crossover components mounted to their boards.
Then, about 500 other things came up and I haven't had a chance to go any further yet.

[djg]

Nice stuff.

I wonder what happened to Serenity Now, he was very eager to build these.

[Steve Lee]

9sheng, your skills have improved markedly over the past several years - you are most impressive.
Please keep this up as you are an inspiration, here and the world-over.

[9sheng]

The materials have been delivered. I use two 18mm overlapping panels and a ring to reinforce the mid-range PVC pipe cap.

[9sheng]

​

[Paul Carmody]

If you do go with this bracing, make sure and take lots of pictures! This is bracing worth showing off!

[9sheng]

Your vision is very accurate. I calculated that the plane area of the internal support is 240428 square millimeters, which is replaced by the plate size ≈ (width) 358mm * (height) 671mm. This size is smaller than the backplane, because the size of the backplane is 358mm (width) * 828mm (height). So I can increase the depth of the box by 18mm (≈ 0.75 inch).

Thank you. I can customize the boards. I am looking for a nearby CNC to process and then assemble by myself, which will reduce a lot of work.​

[Paul Carmody]

I love this! This is the sort of internal bracing I wish I had the patience for (maybe owning a CNC would help).

Anyway, I think some of the career engineers here could probably calculate the exact internal volume taken up by all that bracing. An eyeball estimate from me almost makes it look like you might have the equivalent of like another baffle's worth of wood there. if that's the case, then it'd be a safe estimate to increase the cabinet depth by .75" to 1". Again, these are super-rough eyeball estimates. But that's what I'd do.

[9sheng]

More pictures