SB Acoustics Bromo

[RHO]

I finally finished my last (yes, last, not latest) DIY build. A pair of SB Acoustics Bromo.
It took me way too long to get it done. I just don't have the time nor motivation anymore to build my own gear.
Economically it makes much less sense for me also.
But, I'm really happy with the result. In the end it was worth it. But I don't think I will do it again. (over the years I've build about 10 pairs of speakers and a few amps to) I just enjoy listening more then building now. (for some time it was the other way around!)

Here are some pics for you to enjoy.

The enclosures were quite easy to build, apart from 1 part. The miters weren't perfectly done. So after the first layer of paint I got very small openings at the edges. Getting those filled was harder than expected.
In the end I think it turned out just fine.

The filters fit nicely at the bottom and leave plenty room for the magnet of the low-mid.

I added some Bondum800 and filled the rest loosely with BAF.

I build the fronts out of 2 layers of Ikea APTITLIG cutting boards.

The bass reflex ports are 3D printed to perfectly fit 50mm drain pipe.

The drivers fit snugly.

They currently serve as my new desk speakers.

They were not intended as my desk speakers and I think they are a bit large for the application. Still not sure if they are going to stay.
Initially they were intended for the livingroom, with assistance of a 12" subwoofer underneath each. But I sold the subwoofer drivers and never finished the enclosures for those.

I can say they sound even better than expected. Mids and highs are very clean. The sound is very natural.
Bass, is boomy, but I guess that's the effect of the application. These were not designed for this use.
I hope I'll find the time and opportunity to start measuring them in situ with REW and maybe apply some EQ.
I'm contemplating getting a MiniDSP Flex digital, so I can add the sub (CSS Trio12 in 53L sealed) with Hypex FA252 to the set.

 

[Biblob]

I really like the white and bamboo combination. Smart thinking, using the IKEA cutting boards.
I'm curious about the stiffness of this, compared to a more regular 19, 32, or 18 mm thick MDF board.

 

[RHO]

I really like the white and bamboo combination. Smart thinking, using the IKEA cutting boards.
I'm curious about the stiffness of this, compared to a more regular 19, 32, or 18 mm thick MDF board.

Thank you. I'm quite happy with the aesthetics too.

The 2 layers of the cutting board are much stiffer and harder than MDF. Really, I had to drill the pilot holes for the screws larger, just to be able to get the screws in. (and I'm a fairly strong dude)

 

[voodooless]

It really looks good! I like the bamboo front. Isn't the reflex a bit close to the tweeter? It will probably lower your tuning this way, but that could be intended.

 

[RHO]

It really looks good! I like the bamboo front.

Thank you.

Isn't the reflex a bit close to the tweeter? It will probably lower your tuning this way, but that could be intended.

It is quite close, yes. I can take it out by removing the tweeter and pulling it out trough the tweeter cutout.
But it's about 1x the diameter of the tube away from the back of the tweeter.
I'm actually thinking about stuffing the tube with BAF to diminish the output.

Once I get the subwoofer integrated in the set these will get a high-pass anyway.

 

[mightycicadalord]

Excellent wood working and finish.

Doesn't look too big for the desk but then again I use similarly sized bookshelves on a smaller desk and I like it.

 

[RHO]

Excellent wood working and finish.

Doesn't look too big for the desk but then again I use similarly sized bookshelves on a smaller desk and I like it.

Yeah, I'm still not sure about the size.
I'm going to use them for some time to evaluate the situation. Maybe I'll move everything around on the desk to find a better configuration.

 

[mightycicadalord]

I was curious about the bamboo, If you check my history you can see I recently shared a failed cabinet made from pine. The wood expanding and contracting was too much and the cabinet isn't worth keeping. Would the Bamboo exhibit similar humidity issues long term?

 

[RHO]

I was curious about the bamboo, If you check my history you can see I recently shared a failed cabinet made from pine. The wood expanding and contracting was too much and the cabinet isn't worth keeping. Would the Bamboo exhibit similar humidity issues long term?

I don't think you would have the same issues with bamboo.
I've been using these cutting boards as ... cutting boards and they get wet frequently. No warping or splitting or other deformations.
Pine is quite bad in that way.

 

[xarkkon]

beautiful! pity it's your last pair. would love to see many more projects from you

 

[DanielT]

Beautiful! Good work.

 

[restorer-john]

Fabulous looking speakers and definitely worth the considerable time and effort you put in. Enjoy!

 

[RHO]

Did some re-organizing today. (much more work then you would think)

 

[OWC]

It really looks good! I like the bamboo front. Isn't the reflex a bit close to the tweeter? It will probably lower your tuning this way, but that could be intended.

The only way to tell is doing impedance measurements.

Usually it just gives the port a (much) lower Q, aka obstructing it.
The damping material as well as the path through the bracing is also not very optimal.

 

[RHO]

The only way to tell is doing impedance measurements.

Usually it just gives the port a (much) lower Q, aka obstructing it.
The damping material as well as the path through the bracing is also not very optimal.

From the low-mid to the mouth of the port there is no damping. I left that open. The opening in the bracing is bigger than the port area.

Is there an easy way to do an impedance measurement?

 

[OWC]

From the low-mid to the mouth of the port there is no damping. I left that open. The opening in the bracing is bigger than the port area.

Is there an easy way to do an impedance measurement?

If you have an audio interface, it's extremely easy by just using some amplifier (ideally not a bridged one) as well a something like a 5W resistor (value around 18-33ohm)
It's not always just surface area, but obstruction in general.

 

[RHO]

If you have an audio interface, it's extremely easy by just using some amplifier (ideally not a bridged one) as well a something like a 5W resistor (value around 18-33ohm)
It's not always just surface area, but obstruction in general.

I have plenty resistors and a Aiyima A07 amp, but no analog input.
I'm considering a miniDSP Flex. But that could still take a while before I get one.

Edit: I was thinking about doing some room treatment first. I'm interested in these products: https://www.thomann.de/intl/hofa.html

 

[Wolf]

I must say, the Bromo kit sounds really good. Nice choice there, and I dig the Bamboo!

 

[RHO]

I must say, the Bromo kit sounds really good.

Yes, it does.

Nice choice there, and I dig the Bamboo!

Thank you. It did turn out to be a quite attractive little speaker, if I say so myself.

 

[mightycicadalord]

I have plenty resistors and a Aiyima A07 amp, but no analog input.
I'm considering a miniDSP Flex. But that could still take a while before I get one.

Edit: I was thinking about doing some room treatment first. I'm interested in these products: https://www.thomann.de/intl/hofa.html

Could always just build some treatments. I'll never buy them premade because the mark up is just too high on premades. I have friends that bought a couple 2-3" premades for the same cost it took me to make like six 4" panels. They're super easy to make too, especially with your skills.