Kofi Annan in: "Kofi's Living Room"

[Kofi Annan]

Kofi's living room is a tough one. It's got some serious challenges from an audio perspective and has traditionally been tough to fill with bass.

Here's the current setup:

VPI Scout with Dynavector 20XL
Transistor MC Step Up
Tube Phono Stage
SET 300b DRD (~8W output)
Fostex 206E in 208EZ backhorn w/ Dave's phase plugs and BSC correction circuit

So, anywayze, I like the sound, but the correction circuit is causing a decent efficiency loss, which causes Kofi to push the speakers and Mrs. Annan harder than necessary, in which case the latter causes the former to reduce its volume.

So, I'm looking for a reasonably priced new setup for the living room. Under some deep consideration is the Fostex-225K-with-the-17H-tweeter-in-a-BIB combo. Given the flatter response of the 225K I may not need a correction circuit at all, which may give me the efficiency needed for the 300b amps.

I'd also consider an OB design, like the Visaton B200 (I'd prefer the Supravox Signature Bicone, but I don't have $1,000 just sitting around), which would compromise bass, but might be fun anyway.

Other designs would be considered if I had any decent ideas-- and that's where you come in...

Attached is a photo of Kofi's Krappy living room, complete with amps, speakers, kid toys and feet (feet appear white due to flash). Noting all the eccentricities (weird shape, doorway between speakers, feet), could you, the collective community, recommend some air wrigglers? I really think the 225K deally would be pretty good, but I'm hoping for other suggestions around $500 that would do the trick as well.

So?

Kofi

[Scottmoose]

Well, the first question that springs to mind is to ask what the BSC circuit is for with your existing boxes? The 208ESigma cabinet shouldn't require any. It provides gain up to ~300Hz, and the -3db point of the baffle would be roughly the same (311Hz to be exact) so the former should counter the latter.

Looks to me like your main problem isn't extension, it's just pressurising the room, so whatever you do next, I'd suggest you get a couple of 15in woofers per channel so you're shifting some air.

[Kofi Annan]

[b]Well, the first question that springs to mind is to ask what the BSC circuit is for with your existing boxes? The 208ESigma cabinet shouldn't require any. It provides gain up to ~300Hz, and the -3db point of the baffle would be roughly the same (311Hz to be exact) so the former should counter the latter. [/]

Well, I'm using Martin King's correction circuit for my 206Es (using a 6R parallel resistor), which seriously tames the shout and boosts the bass. I've tried listening to these with the circuit in and out and I really prefer the sound with the correction circuit in.

I guess it was inaccurate of me to state that it's a BSC. It's really to do the above thingee.

Looks to me like your main problem isn't extension, it's just pressurising the room, so whatever you do next, I'd suggest you get a couple of 15in woofers per channel so you're shifting some air.

And how! Any suggestions on the woofers? Would the 225K BIB cause or solve any problems?

Kofi

[Vix]

Hi,

Does it make sense if Kofi builds a pair of BiB-s for Fostex 206 E? Building just a BiB and using the existing drivers would be the cheapest, and perhaps the most effective solution. The Sachiko, and/or Curvy Chang also come to mind. However, as I haven't heard any of them, I can't comment...

Vix

[Scottmoose]

Originally posted by Kofi Annan
Well, I'm using Martin King's correction circuit for my 206Es (using a 6R parallel resistor), which seriously tames the shout and boosts the bass. I've tried listening to these with the circuit in and out and I really prefer the sound with the correction circuit in.

I guess it was inaccurate of me to state that it's a BSC. It's really to do the above thingee.

And how! Any suggestions on the woofers? Would the 225K BIB cause or solve any problems?

Kofi

You mean a shelving filter, right? Hmm. The the values will be off, but whatever floats your boat. Surprising though: it shouldn't need any correction anyway in a horn, as that will damp the rising response the driver has in free air. Could just be that you prefer a duller sound.

Try the Eminence range. Beta 15 or Alpha 15, depending on what you do with them. Good value & quality units. I really don't think you're going to be happy with just 1 driver, however it's loaded, covering the entire frequency range, although I suppose you could try a high-gain double-horn. Alternatively, keep what you've got & add big [sub]woofers to help load the room.

[Kofi Annan]

You mean a shelving filter, right? Hmm. The the values will be off, but whatever floats your boat. Surprising though: it shouldn't need any correction anyway in a horn, as that will damp the rising response the driver has in free air. Could just be that you prefer a duller sound.

Could be, but these things have been shouting at me since day one. Don't get me wrong-- they're great drivers-- but I had to make some corrections. Dave's phase plugs really helped in the highs, but robbed them of some bass. I also added wool felt to the magnet and modeling clay to the frame. I've never treated the cones since I'm a sissy, but I'd consider that at some point.

So, upon adding the "shelving filter" things really got in line. You're right that it's duller, but cashing in some midrange for bass is a good deal in my living room-- especially since this kills the shout altogether.

I'll try listening with the filter out this afternoon. Many things have changed system-wise since I built these, so maybe I can handle it full on now.

Try the Eminence range. Beta 15 or Alpha 15, depending on what you do with them. Good value & quality units. I really don't think you're going to be happy with just 1 driver, however it's loaded, covering the entire frequency range, although I suppose you could try a high-gain double-horn. Alternatively, keep what you've got & add big [sub]woofers to help load the room.

I was thinking Eminence...

Could I get away with a passive crossover for these or maybe a plate amp? Also, I may have to go with a pair for now and upgrade to a quad later. Any ideas on a box or could I maybe even OB them?

Kofi