Last year I bought a pair of Rega tweeters for $10 on CL. I recognized them as Vifa and thought that even if they were blown, which they were, I could get new voice coils from Madisound as I had before for my other Vifas. Well. it turned out that Fred Flintstone had owned these and new VCs are not available. But I kept them and tried a few things to see if I could get them to work. Then I stumbled on an ad on eBay for two 19mm voice coils with silk domes from China for $10. I said what the heck, if they don't work I can't say I didn't try. It took two weeks for them to get here and after some VERY careful positioning, glueing and soldering I have a nice working pair of tweeters for a total cost of $20. I built some cabinets out of scrap 1" MDF, bought some Infinity 2-way L-pad crossovers, and mounted them with a pair of PSB 5t woofers I had laying around. Everything sounds great except that even with the tweeter knob turned all the way up they not very bright. My question is if the resonant chamber on these Regas lower the resonance frequency, if I remove the chamber will that brighten up the tweeters? They are crossed over at 3000 Hz. Thanks!
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Most single 6" polycones will output about 83dB in a speaker, paralleled they would be 90dB.
A 19mm tweeter usually outputs about 88dB. So ought to be loud enough for a single driver with a lot of slack to spare. An l-pad is not a totally ideal way to do things. At full loudness it may put a simple 8 or 16R resistance across the tweeter with some serious upward slope towards high frequencies.
You'd need to draw the circuit to see what you've got. And measure the l-pad's overall resistance.
I don't think the tweeter chamber size matters much. It's just like putting a speaker in a bigger box which gets you more bass, but doesn't affect level in the rest of the range. Anyway, you don't use the bottom end of a tweeter, you filter it out.
It could be your Rega chassis have a weak magnet to adjust level and save Rega using resistors in their designs. Which is the sort of money-saving idea you might use when ordering bespoke tweeters from Vifa. It could be your new coils aren't sitting in the middle of the gap lengthwise.
A 19mm tweeter usually outputs about 88dB. So ought to be loud enough for a single driver with a lot of slack to spare. An l-pad is not a totally ideal way to do things. At full loudness it may put a simple 8 or 16R resistance across the tweeter with some serious upward slope towards high frequencies.
You'd need to draw the circuit to see what you've got. And measure the l-pad's overall resistance.
I don't think the tweeter chamber size matters much. It's just like putting a speaker in a bigger box which gets you more bass, but doesn't affect level in the rest of the range. Anyway, you don't use the bottom end of a tweeter, you filter it out.
It could be your Rega chassis have a weak magnet to adjust level and save Rega using resistors in their designs. Which is the sort of money-saving idea you might use when ordering bespoke tweeters from Vifa. It could be your new coils aren't sitting in the middle of the gap lengthwise.
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Hello Steve. This morning I was listening to a recording of "Stop Making Sense" I made off of the internet. I left the tweeter level adjustments alone and just turned down the bass to a more ear-friendly level and they seemed to even out very nicely. The high-frequency passages on this recording sounded clean and crisp. And with the volume turned up on Swamp they sounded fuller and distortion free. I'm trying to teach myself about speaker design and what the specifications mean and their significance. Thank you for the response. I will go over it a few more times and learn what I can for future projects. Mark B. STL, MO, USA
I really couldn't give you much of an opinion without knowing everything about the speaker.
Drivers, cabinet, crossover values, impedances, bass loading aka reflex or closed box and length of port. It's quite a skilled business to get a speaker sounding right.
A 6" polycone is usually quite well behaved, but the bass coil size makes a big difference to perceived bass. It's not really fair to ask a question without supplying enough detail to answer it.
One thing is for sure, off-the-shelf crossovers are a minefield. What works for a 5" bass may not work at all well for a 6". Or an 8".
Drivers, cabinet, crossover values, impedances, bass loading aka reflex or closed box and length of port. It's quite a skilled business to get a speaker sounding right.
A 6" polycone is usually quite well behaved, but the bass coil size makes a big difference to perceived bass. It's not really fair to ask a question without supplying enough detail to answer it.
One thing is for sure, off-the-shelf crossovers are a minefield. What works for a 5" bass may not work at all well for a 6". Or an 8".
Yes I understand that there is an art to speaker design. From what I have read the proper order is cabinet design, graphing the speaker frequencies, and then selecting the crossover points. I selected these OTC crossovers because the specs matched up with the specs for the woofers, and I know they make a good product at a reasonable price. I did try using some crossover calculator software, but I could not build my own for less than what I paid for these. I do appreciate what you said about the L-pads. I know these Vifas are easy to blow. My other pair are on their 3rd pair of VCs. As long as I have you here maybe you can answer this question. I like to hook up multiple speakers in parallel to get a wider fuller sound without a lot of volume. Is there a limit to how many speakers I can safely run together and can it be measured with an ordinary multi-meter. I have run up to eight pair ranging from 5" to 15" and 4 to 8 ohms with a 50 watt amp. I have put a cooling fan on it and keep the volume down just to be safe. I know that impedances differs if speakers are in parallel or in series. I realize this is a huge question but any thoughts would be appreciated. Thanks again, Mark
You've been VERY lucky not to have blown your amplifier here! 😱
Most speakers are 8 ohms. Most amplifiers can safely drive down to 4 ohms.
Like my Rotel, which has two sets of speaker terminals on the back. But they do warn you not to switch in the second pair if they are 4 ohms. Because then the amplifier would see only 2 ohms, and that is moving into short circuit territory. And the transistors would plain overheat. Or a fuse or trip would go, if you are lucky.
2X 8 ohm speakers in parallel is not a problem because that makes 4 ohms, you follow?
4X 8 ohm speakers in parallel makes 2 ohms. That is bad.
You can wire 4 speakers as a set of 2 series wired speakers (16 ohms), connected in parallel with another similar set. That's actually 8 ohms overall. But some strange things might happen if they are not all the same. A picture below of a configuration that can be wired series or parallel and sounds good. That's all one speaker, in effect.
Advice depends on circumstances. Here's a well designed 6" speaker with 3/4" tweeter:
CA18RLY/22TAF-G
Your eventual design won't be a million miles away.
Most speakers are 8 ohms. Most amplifiers can safely drive down to 4 ohms.
Like my Rotel, which has two sets of speaker terminals on the back. But they do warn you not to switch in the second pair if they are 4 ohms. Because then the amplifier would see only 2 ohms, and that is moving into short circuit territory. And the transistors would plain overheat. Or a fuse or trip would go, if you are lucky.
2X 8 ohm speakers in parallel is not a problem because that makes 4 ohms, you follow?
4X 8 ohm speakers in parallel makes 2 ohms. That is bad.
You can wire 4 speakers as a set of 2 series wired speakers (16 ohms), connected in parallel with another similar set. That's actually 8 ohms overall. But some strange things might happen if they are not all the same. A picture below of a configuration that can be wired series or parallel and sounds good. That's all one speaker, in effect.
Advice depends on circumstances. Here's a well designed 6" speaker with 3/4" tweeter:
CA18RLY/22TAF-G
Your eventual design won't be a million miles away.
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Thank you very much for the information. It will take me a while to go over this. What I plan to do in the future is use more amplifiers with a common source of material. I have read about doubling up on amps as long as they are exactly the same model for each channel. I'll have to go back and reread the article before I do any wiring. I understand what you mean about wiring in series and then in parallel. Thanks again for all the material. Nice to talk to someone who understands this and can give me good advice.
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