Hi planet IX, cool! Sounds like you're doing pretty well 
Regarding the placement in the room, take a look at this article by Earl Geddes, where he explains why the "toe in" may indeed be preferred with controlled-directivity speakers like the OSMC (I am not saying that this is the universal truth for everyone, but it does make sense).
Also, regarding your asymmetry to the right side, I used to have such issues too (before developing the OSMC). I kept thinking it's the room for a long time... but once I decided to get to the bottom of it, it turned out that there was a very subtle issue with the configuration in my DAC / software that caused the problem. I suggest you try swapping things from left to right to make sure that your asymmetry is really related to the room: swap out the speakers between left and right, swap the connections from the power amp(s) to the speakers, swap the connections between your source(s) and the power amp(s), etc. This may be a bit of work, but it really helps to figure out where the problem really is.
Regarding the placement in the room, take a look at this article by Earl Geddes, where he explains why the "toe in" may indeed be preferred with controlled-directivity speakers like the OSMC (I am not saying that this is the universal truth for everyone, but it does make sense).
Also, regarding your asymmetry to the right side, I used to have such issues too (before developing the OSMC). I kept thinking it's the room for a long time... but once I decided to get to the bottom of it, it turned out that there was a very subtle issue with the configuration in my DAC / software that caused the problem. I suggest you try swapping things from left to right to make sure that your asymmetry is really related to the room: swap out the speakers between left and right, swap the connections from the power amp(s) to the speakers, swap the connections between your source(s) and the power amp(s), etc. This may be a bit of work, but it really helps to figure out where the problem really is.
Thanks for the article!
As for the asymmerty, I checked all the things you suggested some time ago, but I will do it again.
What I said was my first impression after 2 hours of listening and I didn't expect everything to be perfect right from the beginning.
Now the optimazition-phase begins
I placed the speakers with the tweeter and midrange closer to the middle as I thought this would also help a bit, right?
As for the asymmerty, I checked all the things you suggested some time ago, but I will do it again.
What I said was my first impression after 2 hours of listening and I didn't expect everything to be perfect right from the beginning.
Now the optimazition-phase begins
I placed the speakers with the tweeter and midrange closer to the middle as I thought this would also help a bit, right?
Yesterday, when I put the x-over in its final place, I noticed that I swapped the cables of one of the midrange drivers. So the polarity was reversed and this is why I had the asymmetrical soundstage (note to myself: don't connect anything temporarily after you had a couple of beers)
Now everything is fine and I'm very happy with the result.
Amazing speakers! Thank you Matthias and all others that made their contribution!
Now everything is fine and I'm very happy with the result.
Amazing speakers! Thank you Matthias and all others that made their contribution!
I find it hard to provide numbers on this. Turning this around: what do you have in mind? How big is your room and listening distance?
The listening room is part of a larger open plan area, but the room itself is 14.4m2, listening distance (baffle to ear) is around 2.7m. The distance between speakers (between baffle centres) is around 2.5m. I will pm you an annotated floorplan. Thanks!
@maximax77 Its a VERY rellevant consideration for you to get the right sound. My sweet father forced me to buy the biggest model from CVs AT line and paid the difference from the smaller model I went to get from the shop. -He was tired of driving me around in the country to buy smaller upgrades to what I had. Result was awful sound in my small room😄. I wonder if there are threads on the forum where questions about roomsizes are answered. I guess that is one of the few questions that an experiensed salesperson/installer would be right one to ask.
Cheers!
Cheers!
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Thanks for the PM with your drawing. My OSMC setup is also in an otherwise open part of the room, distances are not very different from yours. I will try to move my speakers according to your distances and report back.
I don't expect anything bad though. The controlled directivity of the OSMCs reduces the impact of the room quite a bit.
Many thanks @Guerilla, @Brett and @mbrennwa. A couple more questions:
- What is life with 12” woofers like - do such woofers penetrate walls even at low-moderate volumes, setting me up for eternal trouble with the wife, neighbours etc?
- @mbrennwa are the tweeter waveguides currently in stock?
- @mbrennwa again - are the forthcoming 3” mids from Bliesma giving you the itch to develop a OSMC v2?
It has nothing to do with driver size. 50Hz at 90dB from a 12" driver is exactly the same as 50Hz at 90dB from a 5" driver. Same amount of air is moved so the transmissibility of the sound into an adjacent space will be determined mainly by the building, SPL and frequency, and not the driver size.
As Brett explained, the size of the woofers is not related to how well you get along with your neighbours. Your neighbours will mostly worry about how loud you're going.
Yes, there are still a few in the box from the last batch.
Nothing wrong with the Bliesma per se, but I don't see why it would be worth the trouble to start from scratch with designing an OSMC with a Bliesma mid. The Bliesma does not have a waveguide like the Volt, and the Volt is a time-tested design. A new OSMC design using the Bliesma would require us to design a waveguide for the Bliesma, and redo the xover. That would be a lot of work, and I don't see why/how the result would be better than the OSMC with the Volt.
Do you mean passive triamping? Where you leave the passive xovers in situ and use multiple amps? It technically may be possibe to do (don't have the xover schematic in front of me as I type) but it's a complete waste of time money and effort (we have an acronym for that here). Don't bother.
This is a well thought out and refined design, and if you're asking this sort of question you don't have the knowledge or experience to improve on it.
Using a dedicated amp for each driver ("triamping" in this case) is possible. Just connect the woofer/mid/tweeter filters to each amp separately. I am sure some people will say that this will improve the audio performance. I personally don't think that three amps are better than a single (good) amp. Also, remember that the OSCM was designed to be an easy load for the amplifier, so even "small" amplifiers will be happy with the OSMC.
If you are asking for active filters, that's possible too. The filter functions are shown in the OSMC paper, and I can provide the data if needed. You'd have to exactly reproduce these filter functions using your x-over. Again, some (many?) people will argue that active sounds better than passive. However, my experience with the miniDSP active filters that we used during the OSMC development was quite the opposite. The sound quality was much better with the passive filters (yes, the filter transfer functions were identical). You can find the details somewhere buried in this thread.
What exactly is the reason you are considering using multiple amplifiers?
Yes I mean triamping. The reason is that i discovered that some cheap tripath ta2024 implementation is very good for hi/mid and something like icepower asx2-50 can drive bass fine. So in total it will be easier to do and cheaper(!) than xover (except additional wires but this is not a problem). So if it can even improve perf, then I can give it a try. The only doubt is amps agreement (2 x ta2024 vs asx2-50) but from my expirience they could match.