So some options are:
1. Active (signal level) equalization, which isn't that difficult, implementing a 6dB step.
2. Passive (speaker level) equalization using either RC or LR network.
I agree that LR in series with driver is better than RC in parallel with driver, as long as the amplifier has the voltage to drive the high impedance.
So, what's a good starting point frequency ... gotta start somewhere ... calculate starting frequency from width of front baffle?
(sooner or later, I'm going to break down and buy a Behringer unit ...)
1. Active (signal level) equalization, which isn't that difficult, implementing a 6dB step.
2. Passive (speaker level) equalization using either RC or LR network.
I agree that LR in series with driver is better than RC in parallel with driver, as long as the amplifier has the voltage to drive the high impedance.
So, what's a good starting point frequency ... gotta start somewhere ... calculate starting frequency from width of front baffle?
(sooner or later, I'm going to break down and buy a Behringer unit ...)
Short version; take your -3dB point at 4560 / width of the front baffle in inches. Another one to add to the reading list: http://www.t-linespeakers.org/tech/bafflestep/index.html The calculators above are also useful.
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I am surprised that nobody asked the obvious (big ones) first...are you absolutley sure that both drivers are wired correctly? By absolutely sure, I mean check both of them now. One wired backwards will ruin everything, as will both backwards. Second, how are the speakers placed? If they're on stands, you will probably lose a bit of bass without floor reinforcement. If they are very near sidewalls, you may be hearing nasty early reflections garbling everything up. If the room has lots of hard floors, sound will suffer (my listenning room sucked so I put down rugs all over...still not up to snuff).
Lastly, and this may be an optical illusion in the supplied pics of your enclosures, but it appears that all of the interior panels (the ones running from one side to the other defining the shape and path of the horn) are not of exactly the same width. This will cause leaks, which will have a tremendous effect on sound as well as bass output. A tiny leak could do it. If you're close to just tossing these cabinets, slather in a bunch of construction adhesive and clamp them up. Also, any cabinet vibrations will color the sound and can even cause a collapsing soundstage (ask me how I know). Less than desirable construction materials will contribute to this. If there is any improvement from sealing up the cabs better, consider just "doubling up" wall thickness by layering on a nice plywood (if you don't desire to rebuild). Heck, even adding on another layer of the cheaper material may help. I have no experience with the 207, but I do have a lot of experience with plenty of other drivers and I have been down this path before. All of the things I have mentioned I have had dealings with. Good drivers get bad real quick when there's a kink in the hose somewhere...
Lastly, and this may be an optical illusion in the supplied pics of your enclosures, but it appears that all of the interior panels (the ones running from one side to the other defining the shape and path of the horn) are not of exactly the same width. This will cause leaks, which will have a tremendous effect on sound as well as bass output. A tiny leak could do it. If you're close to just tossing these cabinets, slather in a bunch of construction adhesive and clamp them up. Also, any cabinet vibrations will color the sound and can even cause a collapsing soundstage (ask me how I know). Less than desirable construction materials will contribute to this. If there is any improvement from sealing up the cabs better, consider just "doubling up" wall thickness by layering on a nice plywood (if you don't desire to rebuild). Heck, even adding on another layer of the cheaper material may help. I have no experience with the 207, but I do have a lot of experience with plenty of other drivers and I have been down this path before. All of the things I have mentioned I have had dealings with. Good drivers get bad real quick when there's a kink in the hose somewhere...
I do a lot of critical listening in mono (single loudspeaker and single monoblock amplifier). I do this especially during component development (loudspeaker or amplifier), when I'm making minor tweaks and adjustments that aren't always replicated on both channels for stereo listening. This also allows me to focus on many performance attributes while minimizing stereophonic effects.
I also pay a lot of attention to phase, in which reverse connections would be a glaring blemish.
A variety of different orientations, but I'm afraid the problems I'm hearing a far worse than placement optimization.
Yes, this would be a grievous problem! The construction is very well-fitting. All of the common dimensions were cut with a calibrated table saw fence without any readjustments between each piece - the pieces fit without gaps. I'll seal it up with (insert goo here) as one last attempt.
Again, the problem I'm hearing are far worse than cabinet coloration. I'd be much happier if the sonics improved enough so that soundstage became an issue.
Here's the real problem. I can make a good driver sound "marginal" with a cardboard box and duct tape cabinet (yes, I've done it before). With these FE207Es, I can't even summon "marginal" sound in sealed, vented, or horn.
I'm also not a novice speaker builder. I have been a serial loudspeaker builder for 20 years, since my first set I built when I left home for college. I've had these Fostex drivers for a few years now, and after a handful of cabinets, I still haven't got anywhere with them.
I'll be implementing the step filter this week, and failing that, going open-baffle.
Ah, so the panels looking as if they are not of the exact same width is a pictoral illusion. I figured that it was, but it's worth mentioning as a shadow or two in the image made me suspicious.
If this is the first fullranger that you've owned (which doesn't sound likely at all), then perhaps you don't like the sound of a single driver. That still wouldn't fully explain what you are lamenting about, though. I'm kinda out of ideas. I suppose that there could be a such thing as a displeasing driver from our beloved Fostex. Dunno. I want you to succeed but I can't help any further. Maybe that OB is gonna fit you just fine...
I try to help and then you slap me with pointing out the spelling mistakes?!?! 😉
If this is the first fullranger that you've owned (which doesn't sound likely at all), then perhaps you don't like the sound of a single driver. That still wouldn't fully explain what you are lamenting about, though. I'm kinda out of ideas. I suppose that there could be a such thing as a displeasing driver from our beloved Fostex. Dunno. I want you to succeed but I can't help any further. Maybe that OB is gonna fit you just fine...
I try to help and then you slap me with pointing out the spelling mistakes?!?! 😉
Thanks. I suppose the last few posts are somewhat superfluous until I get the baffle step compensation working, and tinker with a few more things. Otherwise, I'm just blowing more hot air (which I have been known to do). I need to work through some tweaking and ideas until I legitimately have anything more to say on the subject ...
It was too tempting ... thanks to Micro$oft ... good form, thanks ...
Have you run impedance tests on the drivers... i'm now wondering if you got a duff pair of speakers.
dave
dave
Kashmire:
Sorry if I've missed it, but I don't recall a mention of other speaker (types) that you use in your critical listening sessions, or if you'd had occasion to hear other models of Fostex drivers that you found more tolerable than the 207 (so far).
More than just being disillusioned by what you've heard to date, it could well be that any type of full-range driver is just not for you. I know for example that if my first exposure to single driver speakers was some of the very expensive but poorly integrated Lowther front horns / bass bin systems at VSAC in 2001, it would have taken a leap of faith to wade in the pool. Fortunately that was not the case, and I've had more enjoyment during the past decade (already!) with building and listening almost entirely to single driver systems.
Sorry if I've missed it, but I don't recall a mention of other speaker (types) that you use in your critical listening sessions, or if you'd had occasion to hear other models of Fostex drivers that you found more tolerable than the 207 (so far).
More than just being disillusioned by what you've heard to date, it could well be that any type of full-range driver is just not for you. I know for example that if my first exposure to single driver speakers was some of the very expensive but poorly integrated Lowther front horns / bass bin systems at VSAC in 2001, it would have taken a leap of faith to wade in the pool. Fortunately that was not the case, and I've had more enjoyment during the past decade (already!) with building and listening almost entirely to single driver systems.
Thanks for the encouragement. The quality of people participating on this forum is truly impressive.
Status: I tweaked wraps on an inductor coil last night, and will try the baffle step compensation tonight. I also damped the cabinet walls with a bit of neoprene, and I'll experiment with stuffing.
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