Indian equivalents of the following DIY items.

[roadkill]

I wanted to use a Vifa TC18WG49 for each speaker. I initially considered a 3-way, using a pair of 4" Peerless India drivers I have, but then the crossover design got a bit hairy, and I'm not confident winding so many inductors. So it's a two-way, with the Vifas for woofers and a locally available 1" dome tweeter (marked BPL industries, but I'm doubtful). They sound good, tho, and have a resonance freq. of 1.5kHz. The peak is not very much higher than average, only rises to about 18 ohms (8.8 ohm nominal), measured with Speaker Workshop and an impedance jig. Could it be they are damped with ferro fluid? I bought these tweeters from SP road, this guy named "Speaker Babu". You can identify the shop from the constant "bump bump" of too many subs playing Hindi film music remixes

No, no tee nuts for today. I got Two Towers on DVD and proceeded to watch the battle scenes about 20 times This is getting *way* off topic. What say we start a Wiki on getting components in B'lore, Mumbai, etc.? That way the endless-thread-itis prevalent will not be so bad. Think it's still OK to have 20-page threads? Try searching for info through them, and wade through tons of posts quite like this one...

[navin]

if the tweeter got a peak at 1.5k you want to XO atleast at 3k. (12db or more). I feel the TC18 might be hard pressed to operate above 2.5k. if you like a silghtly laid back design you might expriment with XOing the TC18 at 25.k and the tweeter at 3k. 12db LR should do nicely.

[Vivek]

Roadkill,
I am using the TC18WG49 too with D27 tweeters. What box volume are you using and is it a ported design?
I am using 12dB Bessels for both LP and HP filters. I was wondering if I should reverse polarity for the tweeters. I have tried both but there does not seem to be much difference.
I was thinking whether we can use a simple bolt and nut with a washer on the inside to mount the drivers. Once a T nut in hammered in, it may be difficult to remove it in case it gets all rusty. What say?

Vivek

[tcpip]

Originally posted by Vivek
I was thinking whether we can use a simple bolt and nut with a washer on the inside to mount the drivers. Once a T nut in hammered in, it may be difficult to remove it in case it gets all rusty. What say?

I have been using ordinary pointed-end wood screws for mounting drivers. Drill a hole in the MDF somewhat thinner than the screw, and just tighten the screw in. Angshu says that MDF tends to crumble if you remove and re-fix such screws many times in the same hole. My answer to that is that I'll turn the driver around by 20-30deg and drill a fresh set of holes after the first two or three rounds, assuming that I'm regularly re-fixing and removing drivers.

Brass T-nuts would be cooler, of course.

Or one can try using the existing steel T-nuts and putting a dollop of grease inside each, where the threads are, before fixing them to the MDF. Thick grease should last a long time and will prevent rust from binding the nut to the bolt.

Just my 10-paise worth.

[navin]

Originally posted by Vivek
Roadkill,
I am using the TC18WG49 too with D27 tweeters. What box volume are you using and is it a ported design?
I am using 12dB Bessels for both LP and HP filters.
Vivek

at what freq?

brass T nuts are best and use brass screws too or teh rust of the screw will jam the t nut. i'd use silicone on steel t nuts it is a lot cleaner.

plain old nuts will loosen over time. a wood screw would be better.

[Vivek]

Tarun,
I did what you suggested i.e drill a hole smaller and use wood screws. I was just worried because the tweeter holes have already lost the threading.

Navin,
I have crossed them over at 2500Hz and internal volume will be 73L. That is what I got with an online box volume calculator. Of course, I need to do some testing with Speaker Workshop. But I do not have a measurement jig and I don't know when I will find time to do all that. But for now, I plan to just hook up all this and do some breaking in. The serious testing will come later.

Vivek

[navin]

73L for 1 6". looks awful big. check those measurements. i'd recomend about 20-30L. well if you have built the box maybe you can add a 6 or 8" later for BSC.

[Vivek]

I built the big box in case I decide to add a bigger woofer, perhaps for a 3 way or something like that. About the 20-30 L you are talking about, what alingment will it be? Win ISD says 73L while the calculator at www.lalena.com/audio says I need to use 55L for the TC18. I just do not understand.

Vivek

[navin]

Butterworth B4

Vas = 44 lts
fs = 37 Hz
Qts = 0.47
D = 13.8 cm
Dimensions

--------------------------------------------------------------------------------
Vb = 55.89 lts

= L x W x H
f3 = 31.87 Hz
fb = 35 Hz
Dv = 5.08 cm
Lv = -3.4 cm

[Vivek]

So, do I try with 55L first? Sorry to ask so many questions but I am confused.

Vivek