I am about to finish building my speaker enclosures so will have to think about the veneering. I don’t have a press or vacuum bag so will either have to outsource it or do it like @Sorenm:
-your picture above looks like you used sticks the gradually bring down the veneer onto the contact glue. But how come the sticks didn’t get stuck?
-Not sure if contact glue/cement works in my case anyway because I have used epoxy in quite a few places, not sure if the stuff used for veneering binds to epoxy.
Thoughts welcome.
-your picture above looks like you used sticks the gradually bring down the veneer onto the contact glue. But how come the sticks didn’t get stuck?
-Not sure if contact glue/cement works in my case anyway because I have used epoxy in quite a few places, not sure if the stuff used for veneering binds to epoxy.
Thoughts welcome.
The beauty of contact cement is that it primarily sticks to itself, so the spacers/sticks come off easily after positioning the veneer. You point about epoxy is correct, as far as I understand, but it would depend on where and how much epoxy was used. Some of the wood working pros may have insights.
Epoxy for filling voids? No issues there, rough it up a bit with 100 grit. The contact cements are neoprene based. Very low VOC. Buy a veneer that is paper backed unless you have a pre-shrinking process that's foolproof.
https://www.veneersupplies.com/
Wealth of knowledge there, not sure about shipping to UK. Vacuum bags have their uses, but for this type of work they can cause a few issues when it comes to dealing with clean edges—contact cement, hand rolling and flush-cut bits (or veneer saws) are a better move.
https://www.veneersupplies.com/
Wealth of knowledge there, not sure about shipping to UK. Vacuum bags have their uses, but for this type of work they can cause a few issues when it comes to dealing with clean edges—contact cement, hand rolling and flush-cut bits (or veneer saws) are a better move.
For the electronics, I spent some time getting quotes from different shops. In the end, the Volts were sourced from Solen, the Faitals from Parts Express and the ScanSpeak from audio-hi.fi. It proved difficult to get quotes for all the Mundorf crossover components even though I tried multiple US, CA and EU shops. I suspect the reason is that some of the parts are not typically stocked and the shops had a hard time getting pricing/availability from Mundorf. Just speculation though. For comparison, and because I am a Dane, I sent a note to Jantzen (Danish company, at least formerly) and got a surprisingly swift reply. They helped spec closely matched component options from their assortment. These likely were a little pricier than the Mundorf BOM, but after much fretting over possibly changing the voicing of the speakers, the Jantzen parts were ordered. Unless there are other OSMCs roaming Colorado, it will be hard to determine to what extent a different brand of crossover components impact the final sound, but hopefully, the end product will be pleasing to my ears.
The cross overs were built on three boards and will be place inside the speaker cabinets.
The cross overs were built on three boards and will be place inside the speaker cabinets.
If contact glue is not usable or you need to (eventually) reposition the veneer here is an alternative (PVA+iron method):
https://oakwoodveneer.com/ironon.html
I realise a photo would help:
The aluminium bracket for the Volt is coated with epoxy, the four recesses in the corners are for magnets so will also get covered with a thin layer of epoxy. I will have to fix more blemishes so there will be other areas covered with probably body filler. Maybe I’ll have to use a combination of contact cement and epoxy for the veneer, then clamp.
The aluminium bracket for the Volt is coated with epoxy, the four recesses in the corners are for magnets so will also get covered with a thin layer of epoxy. I will have to fix more blemishes so there will be other areas covered with probably body filler. Maybe I’ll have to use a combination of contact cement and epoxy for the veneer, then clamp.
Time for another update. After much fretting about what finish to apply, the boxes were finished with Arm-R-Seal, an oil/urethane mix that was wiped on in multiple coats. I really wanted to use something less noxious but the size of the speakers seem to invite future placement of objects, like cold drinks, on top, so I went for the bulletproof coat. After a few days of applying several coats a day, the cabinets were lined with 8 mm felt (glued) and 30 mm acoustilux (stappled).
The crossovers were mounted on the bottom and back panel, then covered with dampening material. It was easy to order this dampening material along with the crossover components and I didn't shop for the specific foam used in the previous builds in the thread. I am sure there are pros/cons...the acoustilux was easy to apply over the crossovers.
From there, it was just a matter of mounting the back panel and setting up the speakers:
The stands are made from 2"x2" oak and finished in black calligraphy ink followed by urethane, on the excellent suggestion of @pfarrell. They have adjustable furniture feet. All in all, the speakers turned out much better than I had hoped for, and, they made music on the first hookup. They truly sound special, but more about after living with them for a while.
The tweeters were initially wired with 1.2ohm resistors, this being in the middle of the suggested range, but I swapped these with 1ohm after a couple of hours as the level of the treble seemed too low - 1ohm seems perfect with my system. The ports were cut to 11 cm, but I will likely play with shortening these down the road.
Big thanks to @mbrennwa and colleagues for designing such beautiful sounding speakers!!! If you are on the fence about building these, go for it!
And yes - they are huge, heavy and imposing
But the scale at which they play matches.
The crossovers were mounted on the bottom and back panel, then covered with dampening material. It was easy to order this dampening material along with the crossover components and I didn't shop for the specific foam used in the previous builds in the thread. I am sure there are pros/cons...the acoustilux was easy to apply over the crossovers.
From there, it was just a matter of mounting the back panel and setting up the speakers:
The stands are made from 2"x2" oak and finished in black calligraphy ink followed by urethane, on the excellent suggestion of @pfarrell. They have adjustable furniture feet. All in all, the speakers turned out much better than I had hoped for, and, they made music on the first hookup. They truly sound special, but more about after living with them for a while.
The tweeters were initially wired with 1.2ohm resistors, this being in the middle of the suggested range, but I swapped these with 1ohm after a couple of hours as the level of the treble seemed too low - 1ohm seems perfect with my system. The ports were cut to 11 cm, but I will likely play with shortening these down the road.
Big thanks to @mbrennwa and colleagues for designing such beautiful sounding speakers!!! If you are on the fence about building these, go for it!
And yes - they are huge, heavy and imposing
But the scale at which they play matches.
@wwschaff The speakers are absolutely wonderful. I can't say what part the crossovers contribute specifically, but the speakers are coherent, seem tonally balanced and throw a large sound stage. They are more resolving than my sonus Faber speakers and can effortlessly play at higher levels, I don't know if headroom is the term, but they just seen relaxed and musical at both low and high/loud levels. Coming from something like an 8" woofer, the bass is mesmerizing.
I wonder if any of you OSMC builders have played with port length and could share your subjective experience from this?
The OSMC paper states:
"The recommended port length is approximately 8–9cm long, but slightly different port lengths (7cm to 11 cm) can be used to tweak
the bass response. A longer port will cause a lower bass tuning with a softer roll off, whereas a shorter port will cause a higher bass tuning with a slight bass
peak."
I have 11 cm ports, as shortening ports is easier than the other way around, and a cabinet volume of 80l minus the space taken by the crossover components, so likely 77-78l. The dampening consists of 8 mm felt plus 30 mm acoustilux, except for the crossovers which are covered by acoustilux only. I don't have the skills or software to calculate the optimal, theoretical port length for this configuration, and thought I would ask for insights before shortening the ports by a cm or two. I realize ports are inexpensive and reversing any cuts would be easy, but part of the fun is the pondering.
The OSMC paper states:
"The recommended port length is approximately 8–9cm long, but slightly different port lengths (7cm to 11 cm) can be used to tweak
the bass response. A longer port will cause a lower bass tuning with a softer roll off, whereas a shorter port will cause a higher bass tuning with a slight bass
peak."
I have 11 cm ports, as shortening ports is easier than the other way around, and a cabinet volume of 80l minus the space taken by the crossover components, so likely 77-78l. The dampening consists of 8 mm felt plus 30 mm acoustilux, except for the crossovers which are covered by acoustilux only. I don't have the skills or software to calculate the optimal, theoretical port length for this configuration, and thought I would ask for insights before shortening the ports by a cm or two. I realize ports are inexpensive and reversing any cuts would be easy, but part of the fun is the pondering.
Thanks @shadowplay62 !! This is super cool.
On a quick look, and without understanding the theory, it seems the shorter port gives up to a 1 db boost over the longer port below ~150 hz. The difference below the crossover points of the graphs seems slightly larger, but inverse, and I wonder if this would be less audible than above these points given how low in the frequency register this is. Would the slight differences in SPL be further amplified by the room/front wall, or would that be highly room specific?
Thanks again and apologies for the naive questions.
On a quick look, and without understanding the theory, it seems the shorter port gives up to a 1 db boost over the longer port below ~150 hz. The difference below the crossover points of the graphs seems slightly larger, but inverse, and I wonder if this would be less audible than above these points given how low in the frequency register this is. Would the slight differences in SPL be further amplified by the room/front wall, or would that be highly room specific?
Thanks again and apologies for the naive questions.
The interactions with the room are prevalent so it's difficult to say what it is better, you can see it like a fine tuning. Just try the 8cm vent as the modification is not that complicated.
In theory a lower tuning freq gives a lower bass extension at the lower frequencies (f10 is lower), whereas f3 is lower with a higher tuning freq.
11cm -> f3 55.8 Hz / f10 31.7 Hz
8cm -> f3 49 Hz / f10 34.1 Hz
Remember that differences are small and it's a matter of taste.
In theory a lower tuning freq gives a lower bass extension at the lower frequencies (f10 is lower), whereas f3 is lower with a higher tuning freq.
11cm -> f3 55.8 Hz / f10 31.7 Hz
8cm -> f3 49 Hz / f10 34.1 Hz
Remember that differences are small and it's a matter of taste.
