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

[Kustomize]

I mostly listen to House / Rap / HipHop / Rock


I was so confused between the Classix 2.5, Amiga and Tarkus. Now this too?


Good to see a new design coming up!

Thankyou Paul!

[Paul Carmody]

What's on the inside

I was all over the map as to how to create a separate enclosure inside the cabinet for the mids. You can sort of see in my sketches above that I was just going to build a rectangular sub-enclosure. But then I found an old thread here about a pre-made enclosure Eminence makes (https://www.parts-express.com/Eminen...osure-290-5506), and I really liked the idea and design. Unfortunately that particular guy wasn't really big enough for a 5-6" mid, so I went a bit safer and used a standard 6" PVC end cap. I figure this is basically an off-the-shelf part that is available pretty much anywhere. I think it'll work fine, and it will give the woofer the most space possible, letting me squeeze out as much bass extension as I can.

The next step is that I need to properly brace this cabinet. I was eager to fire these up, and so I figured for the sake of experiment I would just let it be a big hollow box. And yeah, it really resonates. Without bracing, it's basically a guitar cabinet. And recordings with electric guitars and upright bass make them vibrate sympathetically. OK, so interesting experiment, but far from ideal for an actual Hi-Fi speaker. So these are going back in the garage for a few days to glue in some bracing.

[joshshetter]

Nice on the PVC cap, will help save a bit of wood in what looks like a wood consuming speaker cabinet.

[Serenitynow]

Does the PVC cap like this work because the driver requires a small sealed enclosure or because it's not playing down to Fs ?

Also, what is the reason for putting it in it's own enclosure instead of just playing into the main enclosure ?

Not being a pain - just trying to learn.

[fpitas]

Without separate enclosures the woofer output will push the midrange cone around, and midrange may bounce around the box and come out the woofer cone. Also, the midrange cone will act like a badly tuned passive radiator for the woofer.

[Serenitynow]

Understand.
But what about the small enclosure for the midrange ? Is the size of it important ?
Thanks

[fpitas]

It affects the frequency response like any sealed box. Generally it's good if the total Q ends up around 0.707, just like for a woofer, just so the crossover doesn't have to smooth down a lump in response. But that depends on the crossover. Some people (like me) think a Q more like 0.5 sounds best for midrange.

[bassman_soundking]

@fpitas
Surprisingly I have a pair of Yamaha 3-ways (NS-A670X) that did just this.
8" woofer, 5" MB in common chamber.
Yes the mid is affected by the 8" lol even being ported.
I can only image if it was sealed.
Idk what they were thinking with this design.
This was a set of free speakers The Good Guys gave me with a higher middle end Denon 7.1 receiver I bought 19 years ago.

[fpitas]

Sure that mid isn't closed back? That's firmly in "white van speaker" territory there.

Also, ported doesn't relieve any pressure near the port resonance. Just as bad, or worse pressure fluctuations as sealed.

[Serenitynow]

Interesting.
Thanks for the Total Q explanation. Now I can see the need for correctly sizing the enclosure.

[bassman_soundking]

Yeah its definitely a MB driver not a midrange and its definitely not in a chamber.

I was looking it up just now and saw others complaining about it as well.
Says 6db x-over 1.5k and 3.5k lol too.

Even though Im not a skilled designer I see issues with the xo as well asa the common chamber design.

All aluminum (alloy) drivers that actually look nice. Tweeter looks a little cheesy though.

Probably instead of selling off extra parts they threw these together and thats why they were free.

[fpitas]

Worth every penny, too!

[bassman_soundking]

They dont sound horrible.
But they are not connected if that means anything.
Too bright and not the best at anything.
Cheap unbraced boxes with a vinyl wrap type covering, but it hasnt come off.
They are going to get sold with several other pairs of speakers that are collecting dust

[djg]

To Paul C's original post, I see that JBL now describes their current L100 model as a "bookshelf" speaker. Seriously. No link per PETT policy.

[Paul Carmody]

Yeah, see? C'mon JBL. What were you thinking? If you're gonna make a big heavy monkey coffin, do it proudly! Don't pretend to be petite. It's like the speaker equivalent of sucking in your gut.

[fpitas]

You guys just need bigger bookshelves.

[Serenitynow]

Back on topic.
Paul, have you settled on midrange choice now ?

[Paul Carmody]

To be honest, it's gonna take a while. My day job has me booked solid most days (and then my kids' various activities at night). I only get slivers of time for DIY. I'd estimate I won't have a final decision on the mid for another 2 months.

[Serenitynow]

Oh damn. Ok.
If there's anything I can do to help this project along, just let me know.

Todd

[djg]

The Serenity Prayer.

[Serenitynow]

Hahaha
If it would help.........I'm all over it

[Serenitynow]

Haven't seen it specified yet .
What tweeters are being used in these ?

[bassman_soundking]

Haven't seen it specified yet .
What tweeters are being used in these ?

It looks like the Peerless D27TG35-06