That is much like the plan, but it looks ugly in the taste of the guy. I showed him the Neumann KH420G and the Kii Three BXT to show what would fit that office on the commercial market, and he thinks those are plain ugly and are no option, how good these technically may be.
He lives in an old castle and want it finished in polished full magony wood (at least the front) to fit the decor. The rooms is his office, but it's also his libary and has the classic wood floor to ceiling bookcases made in magony wood, and a magony floor and ceiling. The speaker should blend in, and will probally be a double layer build, with inside baltic birch (airtight), and an outside cabinet in magony full wood (with room for movement like furniture.
But that layout is interesting, i may go the same way (many things to consider on this).
Thanks adason, I like the second one; how I have imagined using big domes (or small cones) with a tweeter with a small bezel
dave
Stuck in hospital browsing with the phone works OK but posting is a pain
dave
Stuck in hospital browsing with the phone works OK but posting is a pain
Certainly an intriguing idea! These are all good drivers. When choosing the mid/tweeter xover frequency, make sure you get a smooth dispersion. In other words, the off-axis SPL drop should be about the same for the mids and the tweeter at the xover frequency.
I have no advice but having just bought some NOS Peerless domes a few thoughts.
To get the C2C distance as small as possible you need a driver with the smallest faceplate you can find and also the tweeter ditto.
This seems to indicate 50mm domes
Secondly; if you use a 50mm dome they seem to demand a crossover outside of the "telephone bandwidth" and need better design skills than I possess right now.
Thirdly they seem to be screaming 4-Way at me using a 6" bass-mid
So possible configuration SSWMTMW using 10,12 or 15inch bass drivers as the "S"
To get the C2C distance as small as possible you need a driver with the smallest faceplate you can find and also the tweeter ditto.
This seems to indicate 50mm domes
Secondly; if you use a 50mm dome they seem to demand a crossover outside of the "telephone bandwidth" and need better design skills than I possess right now.
Thirdly they seem to be screaming 4-Way at me using a 6" bass-mid
So possible configuration SSWMTMW using 10,12 or 15inch bass drivers as the "S"
Potential construction design for Hardwood baffle:
If it's a large library I'd probably go for Cello Grand Master in aesthetics, I've always thought they would look good in a wood paneled room with a large Persian rug.
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In what respect specifically is it not good with regard to baffle construction (..it obviously wasn't offered for its T-Line design)? If it's way over complicated - how?
To me it looks like a rather nice way to "pull" the baffle to the *cork gasket - making it air tight while allowing for expansion/contraction of the natural wood baffle. The basic driver mounting also looks good to me.
*and also a nice choice of a natural material for the gasket.
To me it looks like a rather nice way to "pull" the baffle to the *cork gasket - making it air tight while allowing for expansion/contraction of the natural wood baffle. The basic driver mounting also looks good to me.
*and also a nice choice of a natural material for the gasket.
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At minimum this will certainly need to be a multiple smaller LF driver 3 way system build to get the most from the mids. It also depends on his amplification and its low impedance drive capabilities. The problem you're facing with an MTM using larger mid domes (larger than 2") is the needed lower crossover point to avoid combing and the need to space them as tight as possible with the HF. Ideally smaller faceplate drivers are appropriate for this. If however, you're thinking of using the Bliesma T34B, I'd just do an WMTM with 2 higher end Scanspeak 6-7" cone mids and put the T34B in a waveguide. You won't be pushing that tweeter hard at all to keep up with the 2 mids, given the sensitivity and WG loading at about a 1.8k 12dB / 1.6k 18dB HP (for proper MTM vert lobe). If you choose to use dome mids, go with the T25B for tighter spacing. To my ears, the T25B sounds better up top, costs less and has a smaller faceplate too.
T didn’t say that wasn’t good, I don’t know etuff, it it is WAY more convoluted than any I have seen here, certainly none of the solid heavy builds I have. Given the”misinformation” I do recognize I would also discount that particular bit until I checked further. And the other parts of the box I do understand (bad) makes me leary… design & construction. And that they think it worthy of big buck drivers.
dave
dave
If this new owner is a good woodworker perhaps he should think about a scroll work wooden grill to simply hide the drivers A La the big Japanese multi-way speakers of the 70's ?
that is something i take in consideration, but i managed to get them close enough to do the crossover between tweeter and mid at 2kHz in my simulations, and both drivers would be very confortable at that point with a 3th order crossover i think. Distance between cones is 120mm, and distance between the two mids in that layout is 130mm. This is what the id is now. on the left the 2 middomes (M74A6), in the middle the tweeter and the woofers (PT8) on the left with the ports above and below the middomes. A bit inspired on the Dynaudio BM3 that someone mentioned here. Like this all drivers are very close to the tweeter.
But as usual a lot of scenario's will be checked before i decide what it will be. This is not final, it's just the id i like the most at the moment.
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I don't think that is a good design, the woofer has no breathing space on the back (it need to have at least some space because ofthe venting hole) and that MLTL is way to small to work well on higher volume. I did sim a MLTL for this driver and it is way bigger than here.
I wouldn't do it this way. The horizontal spread means that the horizontal lobing will be a mess, which will not exactly help the stereo imaging. I'd recommend to keep the drivers aligned vertically.
For example:
The external diameter of the Bliesma M74 is 121 mm. A Scan Speak D2004 tweeter has an external diameter of 55 mm, and a Scan D3004 has a diameter of 62 mm. The D2004 would allow a 176 mm vertical spacing of the mid domes, or 182 mm with the D3004. These numbers correspond to wavelengths of 1950 Hz (D2004) or 1885 Hz (D3004). So, to comply with d'Appolitos rules in my example, you'd want to keep the xover frequency at these values (or lower).
However, I would also look at the dispersion characteristics of the tweeter and midranges, and try to choose the xover frequency to get a smooth match at the xover. Looking at the datasheets of the drivers in my example above, the Bliesma starts beaming at about 2 kHz (or slightly below). The tweeters start beaming well above 3 kHz.
So, an xover frequency somewhere at 1.8 to 2 kHz would fit nicely (no beaming from both the mids and the tweeter), and would be nicely in line with d'Appolitos rule.
That driver config is going to generate some not so desired lobing characteristics around the crossover point and down into the mids. Not that it won't sound good on axis, but it certainly will behave unpredictably off axis. The reason i say this is based on experience with this exact driver setup on studio monitors. Given the output capability of a single 3" dome you're intending to use, it will be sort of a compromise on both ends to use 2 of them based on off axis performance alone, but also due to more complicated crossover design having both mids combine response and gain in a not so easy to manage way. In this situation I feel that less is more.
Changing to scanspeak tweeters is not what he wants i think. He's kind of set on Bliesma tweeters for various resons. I could maybe use the smaller T25 tweeter, i need to check if it can fit. Those are also 68mm wide. That could make it possible to put them only slightly offset of the tweeter. Would that be better? The woofer can go on top and bottom of that mid-tweeter config.
I know a TMW would be simpler, but would it be enough (maybe with 2 woofers so TMWW) to fill the space, the office is 12x7.5m and 5m high. I can't find how loud these tweeters and middomes can go. For cone woofers xmax is mostly the limit, but i don't know for domes.
What Wilsons did he have before in there? Maxxes?
I still don't think this room size is reason to go MTM, and if talking 2khz XO - pretty much using the expensive domes for 1 octave is wasteful.
Going to the T25 will obviously help spacing but reduce the SPL capability compared to the T34.
If the guy is so rich, why not get him to order 1 Ellipticor dome, 1 Bliesma, 1 Volt, compare them and go from there.
Wilson Alexandria's he had. And i'm glad those are gone because they are awfull looking and sounding for me. Very sharp bright and resonant. I did not measure them but i'm sure all kind of resonances are very present when you do that.
He is kind of set on the drivers, and heard some scanspeak based speakers that made him not like those (altough it was probally a bad design, because those are geat). And very rich men are often very stuborn, he definitly is...
But things changed, he changed his mind and want to build them into the wall. There used to be a small chapel setup at the end of that room, that he removed (he is very anti-religious) and he is building a new libary shelf system, a copy of the others in that space to fill that free space. So it's an TMW IB now it seems because i can't fit them as a wmtmw in the space i get. 75cm high x 30cm wid x35cm deep is too little space to fit that speaker in that bookshelf rack. A TMW will fit.
Thanks all for thinking with me, it was informative even if the project changed...