Desktop slims

[dirtbike]

Hello

I'm very new to this DIY speaker thing. When I was a teenager I did make a few loudspeakers in my parent's garage based on the speaker stacks you would see at rock concerts. I also made a pair of Rogers LS5a from plans a few years ago from Kef drivers I think).
I was motivated to make a pair of speakers to increase my knowledge base and experiment with some ideas I have with Bluetooth self-powered devices. I'm a fairly competent electronics engineer and DIYer.
The look and aesthetics of the speaker are very important to me, having seen images of small slim designs on the internet I came up with the design shown below.

I have based the driver and crossover design on the Bantams (thanks Tom Z) except for a larger Passive Radiator

The main features being slimmer, taller, and deeper with a larger side mount passive radiator (which I think looks better in the larger space). The front and top will have rounded edges. To keep the design as slim as possible I have made the sides of 12mm MDF the rest being 18mm MDF with an 18mm brace from side to side. The volume is about 1.5 liters. A small metal box will house the electronics (more of that later). The finish will be a real wood veneer all around. The drivers and crossover components are on backorder due for despatch at the end of May.

While sonic performance is important it also has to look right as well.
I hope my design doesn't compromise the original Bantams design by TomZ too much. Would appreciate any comments

Thanks for having me here on your forum

TomF

[zx82net]

Nice! Just be aware, the larger PR will require more mass to tune it to the same frequency. All of that moving mass may give them a tendency to walk around your desk, have some bluetack ready

[dirtbike]

Thanks for the tip.

I was intending sitting the speakers on springs (rather than spikes and making a mess of the desk) again because I think they will look good, maybe 3 or 4 depending on the weight. Something like these. They are 20mm in dia and 30mm long.



They are a bit stiff in the compression sence. I intend to recess them into the bottom of the case with only a few mm showing. Now I will consider putting some rubber on the bottom of them as well

TomF

[Chris Roemer]

If you use the ND105-PR, and have approx. 0.07cf NET (2L), the tuning looks good w/NO added mass, w/an F3 below 80Hz.

[dirtbike]

Thanks Chris for your comments, but I was considering the Dayton Audio Designer DSA135-PR 5 inch which fills the space better than the 4 inch driver.
What do you think about that?

TomF

[Chris Roemer]

PERFECT ! - w/NO added mass. And your F3 will reach about 10Hz lower. (Tunes 2L to the mid 70s.)

The ND will be Xmax-limited near 28wRMS @ 65Hz, w/that PR stroking about 1/2" (p-p).

[tomzarbo]

PERFECT ! - w/NO added mass. And your F3 will reach about 10Hz lower. (Tunes 2L to the mid 70s.)

The ND will be Xmax-limited near 28wRMS @ 65Hz, w/that PR stroking about 1/2" (p-p).

Nice!

And to ZX82net's comment. I have small soft rubber feet on the bottom corners of my original 'Bantams' and they still move around a bit. I'm guessing the 'Passive Aggressives don't have this issue as the PR's are opposed, but the little 3.5" Peerless PR in the Bantams has enough weight to make the speaker dance all over the place if not 'glomped' down somehow, so your larger, weightier 5" PR will likely want to make the cabinet move about even more.

Your spring idea looks interesting... I think they would need to have enough 'give' to absorb some of the vibration, just me thinking out loud, and thinking they look like automotive valve springs. Maybe they are more compliant than they look, though.

This looks like it will be a pretty good speaker, I'm looking forward to seeing it created. I hope you post pics as you go, I'd love to see them.

TomZ

[3rutu5]

2L is quite compact, what driver are you using,? ND90/91?

has a Boenicke W5 inspired feel to this, I like it. I'll be watching how this one goes as being 0.07 cuft it fits my current requirements for my desktop build

[dirtbike]

Thanks for all your positive comments. Yes other drivers are the same as Bantams -

Dayton Audio Designer DSA135-PR Passive Radiator (DSA135-PR)
Dayton Audio ND91-4 Bass-midwoofer (ND91-4)
Dayton Audio AMTPOD-4 AMT Tweeter Matched Pair

You are correct they are W5 inspired - well spotted.

I hope to be starting cutting wood in June.

I'll keep you posted.

TomF

[3rutu5]

i started off basing my desktop speakers to look like them, kerfed the timber and got that shape, but then went away from the passive on the side. I was actually thinking about something similar this weekend with getting a pair of those 3inch tang bands and going a sub on the side and some full ranges on the front.

Good luck and ill be glued to this.

[dirtbike]

Thanks.
I won't be using solid wood like the W5. But if these go well I may attempt a clone of the W5

TomF

[dirtbike]

Working out the best way to round the top, bottom and back edges - about 25mm radius. I was going to use a router but my router only has a 6mm shank and all the round router bits I can find require a 12mm shank. So I'm going to build the cabinets with quadrant mouldings on the edges using 30mm MDF quadrant as follows.

[3rutu5]

note sure if you are familar with the bending techniquie called "kerfing" check out the below link as it might give you a different way to get that W5 look

http://techtalk.parts-express.com/fo...or-pc-speakers

i did mine and many others with kerfing and it looks pretty good, might be an alternative to using a larger router bit.

[unclejunebug]

Is your router’s collet fixed? No way to remove it and replace with a 1/2” collet?

[dirtbike]

Hi 3rutu5.
I have seen that technique on other woodworking projects but didn't know it was called Kerking. It's a good idea thanks, I guess the thickness of the wood determines the smallest radius. I'm looking for a 25-30mm radius which I think looks about right for the shape and size of my enclosure. What is the radius of your speaker design and wood thickness.
Thanks
TomF

[3rutu5]

Hi 3rutu5.
I have seen that technique on other woodworking projects but didn't know it was called Kerking. It's a good idea thanks, I guess the thickness of the wood determines the smallest radius. I'm looking for a 25-30mm radius which I think looks about right for the shape and size of my enclosure. What is the radius of your speaker design and wood thickness.
Thanks
TomF

That one was a 40mm rad using 19mm.pine. to have a look at minimum cuts vs radius vs thickenss try checking out the online kerfing calculator on the block layer website. They have it in both metric (what i use) and imperial measurements

[dirtbike]

Started a new post called TWF5's small desktop speaker based on the feedback I have had so far.