I have been reading Dr. Geddes, and I want to try some waveguides to control dispersion. This also means I will want 1" compression drivers (like the Geddes ones) but this seems conflicting in a home situation.
Will they respond well to low power, like SET? I've heard these drivers sound effortless due to their ability to play loud, but I feel I could only take advantage of this by forcing them to cross low.
I want them to take the place of Fostex drivers that are doing mid-bass and up, but to me it just seems chalk and cheese.
Will they respond well to low power, like SET? I've heard these drivers sound effortless due to their ability to play loud, but I feel I could only take advantage of this by forcing them to cross low.
I want them to take the place of Fostex drivers that are doing mid-bass and up, but to me it just seems chalk and cheese.
Depending on how you define mid bass, that may not be a good idea. Generally you want a 1" driver crossed over above 1K or so and then you have the issue of the size of the waveguide if you want to go below that. Many 1" drivers won't even play to 800hz at least as far as the minimum crossover points recommended by the manufacturer.
Rob
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What are the crossover points for your Fostex drivers now?? Are you considering droping the waveguides on top of the Fostex's for a 3 way??
Depends on how much padding you have to do and if there will be any passive compensation for the waveguide. They don't need much power but you can eat quite a bit of what is available just padding them down. Usually you are looking at at least 10db depending of the sensitivity of the midbass driver. If you start with 2-3 watts your looking at 200-300 miliwatts at the driver. With a 110db driver that will get you to about 104db or so. That would be at 1 meter so to me not enough for you???
Rob
Depends on how much padding you have to do and if there will be any passive compensation for the waveguide. They don't need much power but you can eat quite a bit of what is available just padding them down. Usually you are looking at at least 10db depending of the sensitivity of the midbass driver. If you start with 2-3 watts your looking at 200-300 miliwatts at the driver. With a 110db driver that will get you to about 104db or so. That would be at 1 meter so to me not enough for you???
Rob
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I wil be listening from 3-4m so 104dB is a good start. I should be able to pick up a few dB as I have some amp options.
I wasn't thinking of going 3-way, but I might consider it while I learn the new driver's capabilities and find a way to go 2-way.
Any idea how the CD would sound above a fostex?
I wasn't thinking of going 3-way, but I might consider it while I learn the new driver's capabilities and find a way to go 2-way.
Any idea how the CD would sound above a fostex?
I don't see what the compression driver has to do with the crossover point. To me this frequency is dictated by two things: The directivity of the woofer at its upper end and the low-end directional control of the waveguide. The compression driver is pretty much irrelavent.
Now in Pro apps this is different because you are using the compression driver near its limits, but in home use these drivers have so much extra capacity that over extending them is simply not going to happen.
And I do not see what limits any driver at low levels:
While I am not a big fan of tube amps, I see no reason why a very high efficiency is not an ideal match for a low powered one.
Now in Pro apps this is different because you are using the compression driver near its limits, but in home use these drivers have so much extra capacity that over extending them is simply not going to happen.
And I do not see what limits any driver at low levels:
While I am not a big fan of tube amps, I see no reason why a very high efficiency is not an ideal match for a low powered one.
I've said this before, but it is worth repeating. Any CD device must have equalization. That's because with CD its power response must be falling along with its axial response. If it "doesn't require EQ" then it is not CD.
Hello Earl
You don't see an issue with a 2-3 watt amp and at least 10db of attenuation on the compression driver potentially not acounting for any of the CD compensation on the waveguide?? That will give him what a couple of hundred milliwatts??
He wants to use them from the Midbass up. So a 100-300hz crossover point is OK with a 1" CD?? Where is he going to get the waveguide forget about matching the directivity at crossover??
Rob
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I will more than likely bi-amp, so I'll get to keep my watts
I'll just need to design a woofer system to meet them, I guess.
To control directivity to 300 Hz would require the waveguide to be about six feet in diameter. Is that the plan? Sounds kind of far fetched to me. No 1" compression driver is going to go down to 300 Hz anyways - I go to 800 Hz or thereabouts in the Summa, but lower than that could be difficult. I think the driver could do, but waveguides of a reasonable size can't.
As you said - is 104 dB enough for you? Its not for me, but then thats "part" of what I don't like about Tube amps. The other part is the high output impedance. Why not just get a good receiver and be done with it? Then who cares about padding the CD driver.
As you said - is 104 dB enough for you? Its not for me, but then thats "part" of what I don't like about Tube amps. The other part is the high output impedance. Why not just get a good receiver and be done with it? Then who cares about padding the CD driver.
FE108 Sigma is a 4 inch driver - is it already on a large front horn/waveguide whose diameter is suitable to match a modest-large CD horn? This type fullrange is usually runs full-out in BLH and in that case may be augmented with a little low-mass tweeter. Where do you want to put the CD horn xover? I don't know much but don't understand the application.
Distortion. It rises very quickly under a certain frequency. Easy to measure, easy to hear. Phase gets a bit strange, too - but that's probably the horn.
I want more, but I have a nice 10W SS amp I'd be willing to use up top. With a sensitivity of 108, that's 118dBW/m I assume, raw, before the waveguide.
I'm using metronomes. They do well for what they are, but they seem to skirt the issue of treating the front of the driver.freddi said:
If I go this way, I'd set up the CD then create a system to meet it from the lower end. (I tend to work backwards sometimes
)What directivity? It's omni down there.
Where's he going to get the requisite "boost" for HF compensation of a constant directivity waveguide? From the active crossover? No free lunch there, either; he still has to have the headroom.
Ttan98 has the best answer: forget about constant directivity, use an exponential horn, and pretend beamy is better.
[I mean, precise imaging with no artificial spaciousness, what's not to like...?
]
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Perhaps the econowave project (thanks to the poster above
) is an interesting read if a 2 way is the way to go for you.Why didn't you mention it Zilch?
By "low levels" I meant signal level not frequency. Yes, operating a compression driver too low in frequency dramatically drives down its performance limits, but at low enough signal levels even this is not an issue. Hence, my comment that I did not see any limitations to a driver operating at "low levels".
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