New DIY speakers finished

[Thomas_A]

I like DIY and made my monitor speakers a long time ago based on a design from a magazine (also sold commercially which I bought 20 years ago) but with different drivers and another filter. Been using the accompanying "subs/stands" a long time but now finished my new subs/stands with better performance. Ported (down firing) and tuned to around 21 Hz which is about one octave lower compared to my old ones (not really subwoofers...). Sound is actually cleaner and less boomy compared to the old ones, probably because the former ported design had a peaking in the 40-50 Hz region. So soon time to measure the system and do some adjustments. Some speaker grilles are coming as well. Will also add my separate active filter laying around (30/18 dB slopes), using HT amp 24/12 today.

 

[pozz]

The cabinet work is: wow.

 

[Thomas_A]

The cabinet work is: wow.

Thanks, the finish is nothing special I would say if you would look closer, but it is good enough for me. Some details in black are missing still, will post an update later.

 

[Ron Texas]

Rather unconventional looking.

 

[Thomas_A]

Approximate response on axis measured in room so gated heavily (no good below 1000 Hz). I like a bit lower energy 2-5 kHz and around 8 kHz.

 

[Thomas_A]

And the in room response at listening position (i.e. including room). I've cut out the region below 100 Hz since I only have measurements with the "old subs" at the moment.

 

[VeerK]

How did you do those angled joints, they look so nice and flush

 

[direstraitsfan98]

The finish almost looks like a Wilson Audio Specialties speaker. That grey is typical of what color they usually come in. That wasn't what you were going for perhaps, was it? Honestly if you swapped out the drivers to Seas ones, it wouldn't look that out of place.

 

[Thomas_A]

How did you do those angled joints, they look so nice and flush

The monitor speakers are built as "one foot cubes", and the slanted with a hand saw. The front is then glued on and trimmed with a handsaw. The same method with the subs. I built several monitor cabinets, and these ones are constrained layer damped MDF 9+9 mm using damping glue from Swedac to remove some 300-400 Hz cabinet resonances.

 

[Thomas_A]

The finish almost looks like a Wilson Audio Specialties speaker. That grey is typical of what color they usually come in. That wasn't what you were going for perhaps, was it? Honestly if you swapped out the drivers to Seas ones, it wouldn't look that out of place.

The model is based on Mirsch Audio but originally as a DIY kit.

But there are similarities also to the later series of Stig Carlsson speakers:

 

[Ben_Vee]

Beautifully made. The surface finish is the part of diy-ing I find the most daunting. My opfen baffle speekers work nicely in our living room soundwise, but still in raw MDF "look". It's ugly, but I have no idea how to achieve the even glossy white surface, I would fancy. I even asked at car body painters, but they are not interested in working with my speakers... Sigh!

 

[Count Arthur]

I studied indutrial design many years ago and we often used MDF for model making. We would first seal the MDF with dilute PVA, then smooth it off and use car spray paints on top. You can use car body filler for any gaps or holes. For a smooth or gloss finish, the secret is building up layers of primer and sanding it smooth with "wet and dry" between coats before applying the final top coat. With metalic paint, you want a final clear lacquer coat on top.

It's time consuming and you have to wait for each coat to completely dry before you start rubbing it down, but with patience, you can achieve a really good finish, however, the paint is quite delicate and won't stand up hard knocks or much handling.

 

[Prana Ferox]

Beautifully made. The surface finish is the part of diy-ing I find the most daunting. My opfen baffle speekers work nicely in our living room soundwise, but still in raw MDF "look". It's ugly, but I have no idea how to achieve the even glossy white surface, I would fancy. I even asked at car body painters, but they are not interested in working with my speakers... Sigh!

Check out the process at this link. The general gist is that it's labor intensive. Also, you really need a decent spray setup you're comfortable with.

 

[Thomas_A]

I agree that you can do much to make the perfect finish. I only made the basal sanding and painting, fine sanding the first layers of paint. It is good enough for me.

 

[Ben_Vee]

Check out the process at this link. The general gist is that it's labor intensive. Also, you really need a decent spray setup you're comfortable with.

Thanks for the link, a very nice guide. But I hope, a white surface is a bit more forgiving than black... The problem I foresee is spraying with the solvent based paints. My workshop is downstairs in the basement and ventilation is poor - and furthermore, there is a direct vent (basically the supply shaft rundiing from basement right to the attic) into the house, so that fumes/smells from solvents quickly spread into the living space.

When I ever finish this part of the job, I'll post some images...

 

[planet10]

Nice looking speaker.

Are those tweeters the very nice Peerless cones with the aluminum dustcap?

And may i ask why the drivers are spaced so far apart?

We did a small surround box with similar construction. It is not all that easy. :^)

dave

PS: 1st post

 

[HammerSandwich]

...there is a direct vent (basically the supply shaft rundiing from basement right to the attic) into the house, so that fumes/smells from solvents quickly spread into the living space.

Ben, if you don't need a smooth/glossy finish, look into Duratex. It's water-based and often reviewed as odorless. (I haven't tried it yet, but it's on my list for this reason.)

 

[Thomas_A]

Nice looking speaker.

Are those tweeters the very nice Peerless cones with the aluminum dustcap?

And may i ask why the drivers are spaced so far apart?

We did a small surround box with similar construction. It is not all that easy. :^)

dave

PS: 1st post

The cone tweeters are the Peerless CT62 H. Quite cheap ones, no longer made, but good for the price.

Not sure what you mean with spaced so far apart. Not sure they are very far apart (except the subwoofer).

 

[planet10]

Not sure what you mean with spaced so far apart. Not sure they are very far apart (except the subwoofer).

In an ideal worls you are trying to achieve a centre-to-centre spacing of less than a quarter wavelength od the cross-over frequency. Given the size constriants of a tweeter & midWoofer that means as close together as possible.

dave

 

[Thomas_A]

In an ideal worls you are trying to achieve a centre-to-centre spacing of less than a quarter wavelength od the cross-over frequency. Given the size constriants of a tweeter & midWoofer that means as close together as possible.

dave

Yes, this is true. But I focus on other design aims. The design is focused on a reasonably good dispersion, heavy toe in, near-wall placement, diffraction minimisation, on axis with timbral adjustments according to the stereo system errors (Shirley et al), slanted baffle + 18 dB/octave crossover, reduced dispersion of tweeter response laterally.