Snell,Jpw, Audio note

[ledzep]

I still buy quantities of that Vifa woofer (now made in the old Vifa factory by Scanspeak) for HB1, JPW & Snell customers who want to replace old drivers with perished surrounds. It has a cast magnesium chassis and a smallish magnet, deliberately so as it was intended for sealed box use. I still think it's a very nice sounding driver. Recently I've been partnering it with a newer, slightly more civilised, 19mm tweeter from Scanspeak's own range. There's still alot to be said for an 8" in such a configuration in typical British homes. Preferable (to me anyway) than thrashing the life out of a 5 or 6" in a ported cab.

Well said there Guy, spot on.

[Reffc]

I still buy quantities of that Vifa woofer (now made in the old Vifa factory by Scanspeak) for HB1, JPW & Snell customers who want to replace old drivers with perished surrounds. It has a cast magnesium chassis and a smallish magnet, deliberately so as it was intended for sealed box use. I still think it's a very nice sounding driver. Recently I've been partnering it with a newer, slightly more civilised, 19mm tweeter from Scanspeak's own range. There's still alot to be said for an 8" in such a configuration in typical British homes. Preferable (to me anyway) than thrashing the life out of a 5 or 6" in a ported cab.

I agree Guy...nothing good about an 80Hz tuned hump which lets nothing of bass texture through, let alone how badly most small ported boxes are designed (ports chuffing due to being too small in diameter). I'm guessing that it's the Vifa M21WGs you're referring to which I understand is still made on the original tooling. Looks very reasonable cost wise. Is the Scanspeak one of the discovery range? I guess it would need some resistance added to balance the load with the 8 Ohm woofer if it's one of the 4 Ohm drivers but the specifications on those tweeters looks good. The SEAS H0737 would probably be a suitable alternative for a little less. Very tempting!

[DSJR]

Not all manufacturers use the port to extend the bass, but then these speakers seem to lose all the bass (early issue AVI actives anyone) in the process, especially if no eq is added to flatten their response.

Got your PM Dan. I sincerely hope you'll be delighted

[istari_knight]

Got your PM Dan. I sincerely hope you'll be delighted

+1 Do keep us updated, I'll be very interested to hear how it turns out

[ledzep]

I agree Guy...nothing good about an 80Hz tuned hump which lets nothing of bass texture through, let alone how badly most small ported boxes are designed (ports chuffing due to being too small in diameter). I'm guessing that it's the Vifa M21WGs you're referring to which I understand is still made on the original tooling. Looks very reasonable cost wise. Is the Scanspeak one of the discovery range? I guess it would need some resistance added to balance the load with the 8 Ohm woofer if it's one of the 4 Ohm drivers but the specifications on those tweeters looks good. The SEAS H0737 would probably be a suitable alternative for a little less. Very tempting!

So just a quick one here,if the port hole is large would it work better?

[Reffc]

So just a quick one here,if the port hole is large would it work better?

Optimal port tuning should ideally have the air velocity limited to under 8m/s. Anything much over that, and turbulent airflow results (Reynolds Number and other boundary layer and friction factors come into play). This can lead to a lot of port noise and inefficiency. Ports can then tend to operate part resistively instead of purely reactively. The simple answer is to calculate the correct diameter to avoid this (length then changes) and to form bell-entry and exits for more laminar air flow. Its simpler in principle than this description might have you believe even although the maths behind it is reasonably complex.

[ledzep]

Optimal port tuning should ideally have the air velocity limited to under 8m/s. Anything much over that, and turbulent airflow results (Reynolds Number and other boundary layer and friction factors come into play). This can lead to a lot of port noise and inefficiency. Ports can then tend to operate part resistively instead of purely reactively. The simple answer is to calculate the correct diameter to avoid this (length then changes) and to form bell-entry and exits for more laminar air flow. Its simpler in principle than this description might have you believe even although the maths behind it is reasonably complex.

So in everyday language what does this mean?

[Yomanze]

So in everyday language what does this mean?

Ports fart if they are not very well optimised.

[take5]

So in everyday language what does this mean?

It translates as: "Buy Snells"

[Reffc]

It translates as: "Buy Snells"

Spot on