I thought about it. I am currently using two 18" TC Sounds Pro 5100's in my OB system, and they really aren't the best driver for OB. So I have contemplated using them as either a woofer for each of the mains, or building them into subwoofers. But if I use them as woofers would I really need the 18WU for the mains?
Using the 18WU's in the centre sealed would allow a tighter bass in the centre.
The issue is the highpass for the 12MUs - it should be crossed to something else at about 1k, so the 18Ws can't be omitted, IMO - certainly not for 18"s.
Am I reading this chart wrong? I currently have the 2 x 12MU's crossing over to the 18", but that is in open baffle system, maybe the frequency response is very different to a sealed cabinet.
And I don't know how to read the chart for things like cone breakup and when it is in distortion. The problem I found out after buying the 18WU's is that it is a mid -woofer and it really doesn't go much deeper than the 12MU mid.
I thought the idea was to avoid crossing over in the 300Hz - x000Hz voice range.
It's based on the HD measurements I posted some time back. It shows the HD of the 12MU is highest at low frequencies and lowest around 1khz. Also that Troels crossed his Seas Center mid at around 1khz. You can experiment. You don't have to avoid crossing at a specific frequency range. We were discussing previously if you can dispense with the 18W completely, and I saw that center channels are actually specified to be able to cover full range, and the baritone fundamental is around 300hz and therefore undertones will be lower than that. Same conclusions - the centers need to support full range, yet the 12MU's distortion rises the lower it's run. Datasheet says it supports 100hz, but that is just a guidance. It would seem weird to cross the 18W at 100hz; 500hz-1khz is more reasonable.
If I am reading this chart right the distortion doesn't seem to rise above that of the median till lower than ~300Hz. Do you have this same chart for the 18WU?
I think you'll find that a baritones fundamental is a bit lower than that stated 300Hz, probably closer to 80Hz, clean midbass for male voice, midrange for female.
Maybe this is why some 10" drivers sound better with some voices?
Maybe this is why some 10" drivers sound better with some voices?
I can't see one reason why this premium product should not be given a listening evaluation first and see whether the distortion might become objectionable.
hificompass doesn't have the 18W Illuminator tested, but it has the Ellipticor, Classics and Discovery.
Here's the 8545:
According to wikipedia, baritone range is G2 - G4 -- 98hz-392hz.
I ran the Dune throatspeak opening through Audacity -- that noise holds at 400hz but starts lower 🙂
Here's the 8545:
According to wikipedia, baritone range is G2 - G4 -- 98hz-392hz.
I ran the Dune throatspeak opening through Audacity -- that noise holds at 400hz but starts lower 🙂
Also, you may wish to read about Pida's Illu3 3-way with 18WU + 12MU - he went for low cross about 600hz.
Troels crossed over his Discovery Centre at 600hz as well, so it seems to be a fairly sensible place to do it.
Cone breakup is at the right side of the graphs where the response peaks at about 4khz and the off axis amplitude falls off a cliff, i.e. you don't run them up this high, i.e. listen to harp and piccolo music through the 18WU unfiltered, and walk around the room - it should not sound very nice.
The differences you want to observe on the low end are the quality and natural fullness of sound between the 18WU vs 12MU. Listen to music with double bass, baritone, kick drums. The 18WU should sound quite good with these things, as should the 12MU, but perhaps not as full weighted. Also, play that test music at higher volumes.
@Lojzek may be right in that you don't discern anything egregious running the 12MU down low; you can find out for yourself in a test box.
Most 3-ways will cross bass-mid in exactly the 300-1,000 region, e.g. ATC usually high-passes their mid-dome at 380hz. The other thing the 18WU should help with is the sound balance after baffle step loss - you can correct for this in your crossover to equalize the midrange depending on your intended baffle width - your open baffles won't be representative here if you're going to put this Center in a box with a baffle.
Another real world test would be to just play the center channel output from a couple of different movie scenes through the 12MU alone vs the 18WU alone. Are you missing clarity, imaging, even dispersion, is the sound different at low frequencies between them? Can you play one louder than the other? Use an opera test disc as well for music - try Te Deum aria from Tosca.
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Can't remember off the top of my head but I think I am crossing the 12MU's over to the 140-15AM dipoles around the 2500hz mark well before the cone break up. The 140-15AM monopoles will cross over a lot lower with LR4 1600hz being the recommendation from RAAL. Being that I am using an active crossover it gave me the opportunity to move the crossover to wherever I wanted. I found around that 2500 to be a fairly decent balance. I would have to repeat the tests with the monopoles because it could sound completely different to the dipole version of the drivers.
For the mid I am thinking somewhere around the 600hz mark might make a decent starting point to cross over to the 18WU's. And for the mains I am thinking I might just put the TC Sounds Pro 5100's in some ported boxes and cross them over somewhere around the 100hz mark for a 4 way on the mains.
For my active system I will probably buy something with a higher QTC around the .7 mark as that is much more OB friendly than what I have.
For the mid I am thinking somewhere around the 600hz mark might make a decent starting point to cross over to the 18WU's. And for the mains I am thinking I might just put the TC Sounds Pro 5100's in some ported boxes and cross them over somewhere around the 100hz mark for a 4 way on the mains.
For my active system I will probably buy something with a higher QTC around the .7 mark as that is much more OB friendly than what I have.
Goran's view is that 3khz or higher is optimal for high SPL, else 2-2.5khz with steep slopes if needing only lower SPL; also that tweaking the pads lets you shape the top end. The 12MU can accommodate any such range. More testing.
What active crossover do you use?
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