ps-180-8 vifa bc25sc06-4 two-way

[arlis_1957@yahoo.com]

this is a build formerly with the ox20 vifa. the ox20 just couldnt keep up with the ps180. i made a change after hearing several iterations at iowadiy. very nice sounding tweeter.
i routed out the little waveguide i had made for the ox20 and while i was at it, i wraped the inclosure with faux black leather. i'll post some pice later.
measured this morning in box. had a good fight with my wt3......i won!
what i have so far. fourth order electrical 4bw @2800, third order electrical 3bw@3300. my only concern is the low impedence on the tweet.
i left the raw drivers turned on so you could see what i had to deal with.

[arlis_1957@yahoo.com]

Re: ps-180-8 vifa bc25sc06-4 two-way

[johnnyrichards]

Re: ps-180-8 vifa bc25sc06-4 two-way

Should be a winner Lowell, I really liked what I heard in the midrange on the Dayton.

[mattp]

Re: ps-180-8 vifa bc25sc06-4 two-way

Very cool, that is a classy looking cabinet. I've always wanted to try something like that, Sonus Faber cabinets always catch my eye.

[scottsehlin]

Re: ps-180-8 vifa bc25sc06-4 two-way

Hi Lowell,

That BC25 tweeter is very efficient, so it need a lot of padding to get down to the level of the PS180. With your low impedance, I am guessing you have a pretty small resistor (3 or 4 ohms) in parallel with the tweeter. You could experiment with a couple of things:

1. increase both the series and parallel resistance on your tweeter L-pad.
2. Take out the parallel resistor altogether and put a series resistor before the high pass network.

If you do this, some of your other high pass values will likely change, but hopefully at least one will work without being too disruptive.

[ReissM]

Re: ps-180-8 vifa bc25sc06-4 two-way

very nice sounding tweeter.

what i have so far. fourth order electrical 4bw @2800, third order electrical 3bw@3300. my only concern is the low impedence on the tweet.
i left the raw drivers turned on so you could see what i had to deal with.

Love the look of the black leather. Very cool.

One question, the tweeter looks like it starts to die at about 13 to 14kHz. Did you measure the tweeter on axis or slightly off axis? Was it measured at tweeter height or woofer height?

Scottsehlin has some good suggestions to increase the tweeter impedance. It might involve some minor changes to your filter though.

The Z phase looks to be ok in the range where the impedance drops to below 4 ohms so that's a good thing.

[arlis_1957@yahoo.com]

Re: ps-180-8 vifa bc25sc06-4 two-way

Thanks..
At this point there is no padding at all.

[arlis_1957@yahoo.com]

Re: ps-180-8 vifa bc25sc06-4 two-way

Love the look of the black leather. Very cool.

One question, the tweeter looks like it starts to die at about 13 to 14kHz. Did you measure the tweeter on axis or slightly off axis? Was it measured at tweeter height or woofer height?

Scottsehlin has some good suggestions to increase the tweeter impedance. It might involve some minor changes to your filter though.

The Z phase looks to be ok in the range where the impedance drops to below 4 ohms so that's a good thing.

I measured on axis at one meter. I will investigate further though.

[jsr]

Re: ps-180-8 vifa bc25sc06-4 two-way

That's odd you're not using any padding on the tweeter. I've found I need to use quite a lot of padding as that tweeter is really efficient.
That woofer stays really smooth up there...not many woofers can do that. Are those woofers still made?

[ReissM]

Re: ps-180-8 vifa bc25sc06-4 two-way

That's odd you're not using any padding on the tweeter. I've found I need to use quite a lot of padding as that tweeter is really efficient.

Lowell: Is there any chance that the volume knob was adjusted in between testing the tweeter and the woofer? I don't have first hand experience with these drivers, I'm just throwing out a possible explanation for your discrepancy with jsr.

[peepaj]

Re: ps-180-8 vifa bc25sc06-4 two-way

Lowell, those look sweet and feel free to drop them off anytime for an extended stay at my house :D . I can see why you have no padding on the tweeter with the specs. for the ps180 - Specifications: • Power handling: 30 watts RMS/60 watts max • VCdia: 1" • Le: 0.69 mH • Impedance: 8 ohms • Re: 6.32 ohms • Frequency range: 48-25,000 Hz • Fs: 48.2 Hz • SPL: 94.7 dB 1W/1m • Vas: 1.43 cu. ft. • Qms: 3.86 • Qes: 0.24 • Qts: 0.23 • Xmax: 4.6 mm • Dimensions: Overall diameter: 7.09", Cutout diameter: 5.71", Depth: 3.06". Maybe you need an even hotter tweeter than the bc25 with 96 db 2.83v/1m.

I was thinking this might make a good mid for a TMWW and with johnny's post about the midrange, what are your thoughts about using it as a mid?

[arlis_1957@yahoo.com]

Re: ps-180-8 vifa bc25sc06-4 two-way

reiss, yes its possible. i was trying to merge nearfield and well. and to be honest the fr on pcd shows it going down alot now, but omnimic likes it. tommarow ill try to get the other finished so i can listen to two.
jsr, they are in the current flyer.
peepaj, whats the little women cookin for dinner? ;)

[arlis_1957@yahoo.com]

Re: ps-180-8 vifa bc25sc06-4 two-way

well i still have a little dip around 2.8k but this at least looks a bunch better. the thing is, it is not in agreement with pcd. kind of wondering about the mic calibration.

[JasonP]

Re: ps-180-8 vifa bc25sc06-4 two-way

well i still have a little dip around 2.8k

*looks at the scale of the graph*
*looks at the graph*
*blinks*

Right, little Is that even 2 db? I mean sure that is likely going to be audible given the location (in the 2k to 4k range) but I doubt its going to be anything glaring. +/-2db from 500 and up is no small thing is what I'm thinking.

[jsr]

Re: ps-180-8 vifa bc25sc06-4 two-way

I can understand the woofer rated at 94.7dB/m being quite a bit lower in baffle due to the baffle step, but the tweeter shouldn't be that low when rated at 96dB/m. Not much being affected by the baffle step at frequencies above 3kHz. Can someone explain to me?...I'm not seeing it.