Re-working Infinity RS-425 speakers

[michaelgp3]

Greetings. I've purchased and installed Silver Flute W17RC38-04 6 1/2” Wool Cone woofers into an Infinity RS-425 2 way, 6 ohm, PR design enclosure to replace missing woofers. These are a match for impedance & sensitivity, with specifications more in line with bass reflex tuning, which passive radiator designs follow. With the exception of the models in DCM's Time Frame line, this is the most expensive (MSRP) speaker that I've seen that used spring terminals for your speaker wires. Everything else is stock, but because the cabinets are in wonderful condition I've sealed up the inside seams with an adhesive caulk (enclosure construction was already solid). I gave it a listen with the stock crossover, and found that the bass & mid-bass registers could use some tuning. I want to understand the crossover before experimenting with it.

There is a 1mH inductor in series with a .25mH inductor on its way to the + terminal of the woofer. Between these is soldered an 8uF non-polarized electrolytic capacitor in series with a 2 ohm, 10 watt resistor which is paralleled across to the wire going to the – terminal of the woofer.

Intentionally left out of the above description are the crossover components feeding signal to the tweeter.

The crossover point is advertised as being at 3.1k hz.

Any thoughts on what, if anything, can be done, or is it just the woofer I picked? (No disrespect meant towards the silver Flute product). Thanks in advance.

[SciFiDogSD]

Looked up the Infinty's & they measure (OD) at 22.5"H x 11.5"D x 9.5"W! Is that correct? If so they come out to roughly a .97 cu ft cab! I take it your wiring them in series for 8 ohm! Ran them through Bass Box and the flute indicates it tends to prefer a ported cab over a sealed cab. With a ported design and using several sizes of ports I came up with an F3 of roughly 100 Hz with an Fb of 38 Hz! With a sealed cab the F3 jumped up, so I'm not quite sure if this is a good pick for this cab!

[michaelgp3]

The cabinet dimensions you list are correct. There is only one woofer per cabinet. If you've found a picture of these, the lower 'driver' is a passive radiator. Perhaps I need to take a page from the White Van folks and glue a brick or 2 inside (to reduce the cabinet volume).

[SciFiDogSD]

ok & thanks! I ran it again and F3/Fb did not change much> F3 of 100.3Hz(ported)! I've never used the 4 ohm version, but have used the shielded 8 ohm version and it is a nice performer in a .46 cab, plenty of bass! I've also been told this by others that the sheilded version is the best of the flute 6.5's..


I did go back for grins & giggles and ran the shielded 8 ohm version and it comes up with a much better F3 of 81Hz(ported). A passive might of some help here, I've never worked with them,but would certainly seem to help

[michaelgp3]

Slight difference in dimensions; I should have looked at your post closer. I have (OD) 22.5"x9.125"x11.25", equal to @ .91 cubic foot internal volume, accounting for parts and braces displacing air.

Silver Flute recommends a 6 liter vented box with a port 1.5" in diameter by 5.5" long. So, 6 liters = 0.212 cubic feet (assuming the port and the air displaced is not included in this figure - I think I need to check with Madisound's tech support on this). My confusion with our conversation is this: how did you arrive at a enclosure volume of .46 cubic feet when Silver Flute recommends .212 cubic feet? Is the difference accounted for by your woofer/crossover/tweeter/bracing/port volumes? Perhaps your shielded woofer helped in this regard.....I did not see a shielded 4 ohm version available when I was shopping.

I'm intending to reduce the internal volume of my cabinet by gluing superballs (each one cut in half) to the back, top, sides, and bottom of the cabinet. This method allows me better control over tracking changes to the enclosures volume, and can only serve to make the enclosure more inert, acoustically.

[SciFiDogSD]

Looks like a lil confusion here. The .46 cu ft cab recommendation is for the 8 ohm shielded version as listed in the item description/parameters! There is no shielded version for the 4 ohm! Giving MAD a call would'nt hurt to help you along! Interesting thing using super balls glued to the interior, learn something new everyday!