Beaming for a 12 cm mid starts at 3 Khz, so it's the crossover point to the RAAL that's important
Ok what about this? lowers another 300mm bringing it down to 1 meter tall.
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One thing intrigues me, what's the horn for?
The Raal already covers the whole upper range from 2-60khz....
The Raal already covers the whole upper range from 2-60khz....
The higher the crossover frequency between two drivers, the closer together you want their centers to be so as to avoid comb filtering.
In this case, it should be a priority to use the short side of the raal to mount it as close as possible to the driver to which it is crossed.
I was trying to go back through the thread to understand about the horn loaded driver, but I can't seem to find it. (I very highly doubt that such a horn can cover frequencies as low as 100hz)
What about the two small drivers, are they covering the same freq range?
A better solution IMO is to get the twin drivers (perhaps use four/side in a tight square formation) to cover the 100-2500hz range and then cross them to the Raal beyond that.
You'll end up with a three-way that should perform really well.
In this case, it should be a priority to use the short side of the raal to mount it as close as possible to the driver to which it is crossed.
I was trying to go back through the thread to understand about the horn loaded driver, but I can't seem to find it. (I very highly doubt that such a horn can cover frequencies as low as 100hz)
What about the two small drivers, are they covering the same freq range?
A better solution IMO is to get the twin drivers (perhaps use four/side in a tight square formation) to cover the 100-2500hz range and then cross them to the Raal beyond that.
You'll end up with a three-way that should perform really well.
The current configuration is Raal crossover over to two ScanSpeak 12MU mids at 4000hz which are then crossed over slightly high to a Tc Sounds Pro 5100 18" woofer at 300hz.
I want to move the 12MU bottom end up to about 1500hz and slip a mid woofer in the 150-1500 hole that is left.
Now that I have the woofers here and have started listening to it I don't think I want to try the slot loaded design idea that I was considering earlier. There doesn't appear to be sufficient excursion to make the idea work properly, I think the risk of causing reflection muddiness outways the potenial gain.
Had I used a higher qts driver it probably would have worked.
Been reading a few articles on this website Designing Loudspeakers - Part 20 Open Baffle Room Responses
and it has given me reason to think that I should perhaps try divorce the bass from the tweeter - mid - mid woofer combination, and use room placement to give better a sound mix.
I want to move the 12MU bottom end up to about 1500hz and slip a mid woofer in the 150-1500 hole that is left.
Now that I have the woofers here and have started listening to it I don't think I want to try the slot loaded design idea that I was considering earlier. There doesn't appear to be sufficient excursion to make the idea work properly, I think the risk of causing reflection muddiness outways the potenial gain.
Had I used a higher qts driver it probably would have worked.
Been reading a few articles on this website Designing Loudspeakers - Part 20 Open Baffle Room Responses
and it has given me reason to think that I should perhaps try divorce the bass from the tweeter - mid - mid woofer combination, and use room placement to give better a sound mix.
You should experiment with that separate bass placement. Work your mains as a 3-way(?) and add in the 18's as subs. ... but don't look to cross them @300hz as separates.
What I am currently thinking is have the Raal dipole tweeters I have coming on top, followed by the two 12MUs mids (facing opposite directions like StigErics) and a ~10" mid woofer all together and away from the walls, and a separate woofer crossed over around 100hz in its own cabinet. And like in that article placed to get the best bass, rather than putting it where the main speakers are, that way it takes the load off trying to electronically boost the bass. Since sub frequencies are omni directional I could place them anywhere, in fact I am considering making a sub couch like I have seen done on these forrums.
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Look, I know we are all throwing advice your way, but you are still lacking the basics. Maybe the 12 mu will not make it to 300hz comfortably, but you DO NOT need to run them all the way up to 1500. Why such a big jump? It makes NO sense at all to use them from 1500-3 or 4KHz only. That's just basic design. If they do not sound good down to 300hz, try 400, then 500 and so on.
I saw your post about the veteran speaker designer 'testing' them for you. Did he measure? Did he properly filter them? I only saw a mention of using a single inductor to bring down the top range. If that is all he did THAT IS NOT A PROPER OR FAIR test. I am not saying that they WILL work low enough to meet the 5100, BUT you are still just flying along by the seat of your pants with all of this and it makes me crazy to see you spend big $$$ and make rash, hasty judgments. You are working with the best drivers on the planet. They WILL sound good with proper implementation. Without, and you might as well buy something cheap for Jaycar.
We all have different opinions of where to take this project, but I think I can speaker or everyone commenting here that you need to proceed methodically. Give what you've got a fair chance. Do not waste time on some crazy looking prototype, overly complicated baffle designm Make a quick dirty proer framerwork to hold the 5100 nice and stable. Then make another baffle or framework to hold the 12mu and the Raal over or beside the 5100. Get it all set-up, run some sweeps BOTH nearfield for each driver to see what they do ON THE BAFFLE OR FRAMEWORK and then again at 1 meter away to see how they integrate with each other. Just laying those 12mu on your TV stand and having a listening impression is garbage. It will never sound good like that. OB and especially nude OB, require judicious use of EQing. Have you seen in StigEriks thread where he posts all of his EQ requirements? There are many bands of shelving and parametric on his multiway, original designs.
Greg
Yes in another email he send me frequency responses showing how they plotted against the ScanSpeak pdf.
I hear what your saying Greg and I don't plan to purchase any more drivers until 1. I know exactly what I need, and 2. I have tested current drivers in a more calculated and methodical way.
First steps first I am trying to design a baffle for the 18" that I can use now and refine down the track.
So the crazy designs stop with this one... Will see if I can make a start on it tomorrow.
(Top not shown to show internals on ends)
I hear what your saying Greg and I don't plan to purchase any more drivers until 1. I know exactly what I need, and 2. I have tested current drivers in a more calculated and methodical way.
First steps first I am trying to design a baffle for the 18" that I can use now and refine down the track.
So the crazy designs stop with this one... Will see if I can make a start on it tomorrow.
(Top not shown to show internals on ends)
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From a contributor on my own thread over at AudioCircle:
BTW I mounted a TC Sounds Pro 5100 18" Neo Subwoofer Driver on a 2' X 2' piece of plywood. The measured response at my usual 2+ meter couch listening location was surprisingly good - far better than the B&C 15" woofer! The 18" especially had far less distortion especially below 300 Hz, and the frequency response plot was smoother up to 300+ Hz (sorry, no pictures yet to post here). The TC Sounds 18" required much less EQ. IMO the 18” is not recommended for use below 50 or 60 Hz because my immediately behind-couch Velodyne DD-15 is preferred (again IMO because at very low frequencies a servo-controlled sub sounds good, and has measurably lower distortion).
Again, I don't know yet whether these measurements of the 18" Vs. the 15" indicate that the 18" woofer would subjectively 'sound' better than the 15" woofer. So far, it appears that the 18" should be OK as long as a steep low-pass crossover (say, 24 dB per octave slope) is used for below the 300 Hz area.
BTW I mounted a TC Sounds Pro 5100 18" Neo Subwoofer Driver on a 2' X 2' piece of plywood. The measured response at my usual 2+ meter couch listening location was surprisingly good - far better than the B&C 15" woofer! The 18" especially had far less distortion especially below 300 Hz, and the frequency response plot was smoother up to 300+ Hz (sorry, no pictures yet to post here). The TC Sounds 18" required much less EQ. IMO the 18” is not recommended for use below 50 or 60 Hz because my immediately behind-couch Velodyne DD-15 is preferred (again IMO because at very low frequencies a servo-controlled sub sounds good, and has measurably lower distortion).
Again, I don't know yet whether these measurements of the 18" Vs. the 15" indicate that the 18" woofer would subjectively 'sound' better than the 15" woofer. So far, it appears that the 18" should be OK as long as a steep low-pass crossover (say, 24 dB per octave slope) is used for below the 300 Hz area.
Nice setup! It looks like you are absorbing the rear wave? Any thought on that?
Hi Stig, thanks! I too have a studio background, so I come from the school of thought that you should not hear your own listening room. That is only one panel for now. I need to do some listening and place the other panels around as needed. In the old location in my room, there were 12 panels concealed behind a curtain all around the rear and sides of the baffles. And then 6 more on the side walls at the first reflection points. I basically have no side walls now in this orientation since the room is 25 feet wide now rather than 25ft deep. After much critical listening, I like the tighter focus of absorbing the rear wave of a dipole much as you appear to as well.
I will most likely need diffusion on the wall behind my head, now that it is much closer than before too. I'd like to do a cloud perhaps, but there is a rather large ceiling fan in my way with this new room orientation.
I don't want to derail SilentScreamers thread, so I'll leave it at that and continue updates here if you care to follow along:
Raal 140, Neo10, AE Dipole 15 in the works
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First generation is to screw top section to top lid or be separate, but had already considered two round poles feeding through top lid touching only top and bottom with some kind of absorbing material around to reduce transfer.
Was 2am when I knocked that idea up, but yes had already considered doing that (was just too tired to draw it up) by putting a 45 degree angle on top of the 45 degree angled pieces and making the lid in two or four pieces.
What made me hesitate was the consequences of the driver above with the MDF sloping the wrong way.
Still thinking about it though.
Current is 2 x RAAL dipoles with AM transformers on there way from Alexandra (through local guy)
the 2 x Tc Sounds Pro 5100's. However many of the 12MUs I should wind up using (still like them very much but question how much range the should cover) and 2 x Tc Sounds Ultra 5400 for a folded horn couch. Once everything is mocked up and tried then more than likely a pair of 8"-10" but not committing to those until much testing.
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A baffle is born... Busy weekend planned, so knocked up a prototype baffle after work today. Still need to do some wings and mount the baffle to the pedistal, and rewire one of the 12MUs back in.
Sound different mounted in the baffle. First thing I noticed is that I have audible sound at only -60 (Ground Sound turn on level).
It got late so it didnt turn it up to regular level, but eveything sounds a little out whach like it needs to be reconfigured pretty badly.
Well this baffle is only a steping stone, and part of the learning curve to see what I do and dont like.
Sound different mounted in the baffle. First thing I noticed is that I have audible sound at only -60 (Ground Sound turn on level).
It got late so it didnt turn it up to regular level, but eveything sounds a little out whach like it needs to be reconfigured pretty badly.
Well this baffle is only a steping stone, and part of the learning curve to see what I do and dont like.
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