Focal 4 inch driver. Fs=64. What to do?

[lineup]

Focal 4K211 4",
90dB, 8 Ohm,
150Hz - 5KHz,
0.96Kg,
Fs 64,
Qts 0.34,
Vas 7.5L,
Polykevlar cone

I have a pair of these old polykevlar
FOCAL 4K211 = 100 mm midrange drivers, 90 dB & 8 Ohm

1. What would you do with them?

2. What tweeter to use?

3. What bass woofer?

4. Crossover frequencies & sloops ( 6dB / 12 dB)?

I would very much prefer to use a Sealed Box design.
But only if this would be alright to get a good speaker.

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Anyone, please.
I need a few hints

[Moondog55]

Some possible ideas here.
Like all 3-ways multiple difficult decisions
http://diyaudio.co.kr/wwwboard1/data/board3/falcon.pdf

As a general rule use the telephone bandwidth as a guide, in my limited experience the wider themidrange bandwidth the better the overall sound of the finished speaker, are you going active or passive in the cross-over??

With-out seeing a waterfall plot or graph or taking measurements you may just have to experiment

[jupiterjune]

Lineup-

I would get go with a Seas tweeter. Anything in the $30 plus range. Just make sure it can be crossed over as low as 2000 hz, if necessary. Silk dome or aluminum--you will have to decide what your prefer.

As for the woofers, Seas or Peerless would be great choices. Two L18RNXP's in parallel should give you a final sensitivity of 87dB 2.83V/m with 6db of baffle step correction. But they are aluminum coned drivers--you may like paper cones better. Whatever woofer you choose, just make sure it can be crossed over up to 1000 Hz if need be.

Crossover points--I like to start with 300Hz and 3000Hz and 12dB/octave. I don't have experience with that particular driver, but these are good starting values for a 4" midrange.

JJ

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thanks jupiterjune for comment

i will see what i can do

i just downloaded a speaker cad calculator freeware
if I put in values of this Focal midrange driver i can see what will do

jupiterjune, you use any such speaker designer cad programs?

[jupiterjune]

Lineup-

I use Xover pro from HarrisTech Audio. It is very useful once you get used to it. It does have certain limitations (ie -- it can't simulate series crossovers), but I have never found them to be a problem.

I find especially useful for adjusting phase response while keeping the impedence in a useful range.

It comes with many driver parameters pre-loaded. I just checked, the 4K211 in there, although it doesn't have "response data" which shows a drivers deviation from the response predicted by the TS parameters.

JJ

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yes. Moondog. and jupiterjune
This is my preference: VERY Wide midrange.
Now, really wide is fullrange .
.... At the expense of some low bass and probably upper, too.

I want to use 12 dB Linkwitz-Riley.

I bought this 4 inch because of the low FS ( 64 Hz )

I might get away with x-over at 250 Hz ( 4x64 = 256 )
Question is how much it will suffer from taking some of the 200-300 range?

I also will consider an expensive Scan-Speak dome
Scan-Speak D2905/9500, I might afford to buy

Is also 90dB SPL .. but 6 Ohm impedance.

Membrantyp: Coatad textil
Impedans : 6 Ohm
Frekvensomfång : 2000-30000 Hz
Effekt: 150 W/2500 Hz
Känslighet: 90 dB/SPL
Resonansfrekvens, FS: 550 Hz
Rek. delningsfrek: >1400 Hz
Yttermått (mm): Ø 104.5
Monthål (mm): Ø 73.5
Vikt: 0.7 Kg

Does it matter much if I have 8 Ohm for midrange and 6 Ohm for BASS and DISKANT?

=================

For BASS I want to use 10 inch ( 250 mm )
As the MID x-over is low, I may use close to subwoofer BASS.
But I will use 2 low bass elements.

I do not know which Brand 10 inch. To chose.
Scan-Speak or SEAS or Peerless I can get from several dealers here.

[lineup]

Here we have most midrange driver parameters.
Like Voice coil, Magnet & diaphragm + electrical data:
Focal 4K211
http://www.audiocraftworks.gr/gr/pag...vers/focal.htm

[jupiterjune]

Scan-Speak D2905/9500, I might afford to buy

I've never used that one, but it is considered legendary by many--I'm sure you wouldn't go wrong with that tweeter.

The Focal specs were the same as those loaded into Xover pro.

I don't think 250 Hz xover will be a problem for the 4k211--unless you play your music really, really, loud.

It does not matter if your woofer and tweeter impedence is lower than your midrange impedence. Unless (possibly) if you are using a tube amp with high output impedence. Aleph's certainly don't have a problem with it.

Just keep in mind if you want baffle step correction, (I always use a full 6 db) then you will want to put two woofers in parallel. Which means you really need "8 ohm" drivers to end up with a 4 ohm nominal impedence. The final sensitivity you end up with will be the same as a single woofers sensitivity -- ie, 87dB for the Seas L18 woofers I mentioned above.

Ten inch drivers would be good choice for the bass. Look for something with Qts close to .4 for sealed boxes. Here is a link for a sealed box calculator if you haven't found one already:
http://www.carstereo.com/help/Articles.cfm?id=30

JJ

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thanks, jupiterjune
good info