Hi everybody,
I recently bought some Seas 27TFF tweeters for my car, and am using some old a/d/s crossovers which I am nearly certain are 2.5k @ 18dB/octave (12dB on the lowpass).
I'm getting a little crackle at very loud volumes, but 2.5k/18dB seems like it should work.
Does anybody think that crossover point is too low for those tweeters?
Or, would I be better off with a shallower slope at a higher point, like 3k or even 3.5k?
(The mids are Dynaudio MW160GT, good up to around 4k according to mfr).
One other thing--I bought these cheaply on eBay, so I suppose that it's possible (but not likely) that they're counterfeit.
I recently bought some Seas 27TFF tweeters for my car, and am using some old a/d/s crossovers which I am nearly certain are 2.5k @ 18dB/octave (12dB on the lowpass).
I'm getting a little crackle at very loud volumes, but 2.5k/18dB seems like it should work.
Does anybody think that crossover point is too low for those tweeters?
Or, would I be better off with a shallower slope at a higher point, like 3k or even 3.5k?
(The mids are Dynaudio MW160GT, good up to around 4k according to mfr).
One other thing--I bought these cheaply on eBay, so I suppose that it's possible (but not likely) that they're counterfeit.
I used 2.2kHz/24dB in my floorstanders. I don't know how loud you play, but all I can say is that I've never had your problem.
Just re-reading your mail, I'm tempted to suggest you check that the crackle is not coming from your mids: how low are you crossing them over (high-pass), or are you running them with only low-pass filters? You can check this quickly by disconnecting the tweeters.
In one instance I have observed, crossing over a tweeter too low resulted in distortion (honking), but I have yet to hear crackling.
Just re-reading your mail, I'm tempted to suggest you check that the crackle is not coming from your mids: how low are you crossing them over (high-pass), or are you running them with only low-pass filters? You can check this quickly by disconnecting the tweeters.
In one instance I have observed, crossing over a tweeter too low resulted in distortion (honking), but I have yet to hear crackling.
sqlkev: Yeah, you're right. The imedance might be different. I measured it with a voltmeter, but that's the just coil resistance, not the nominal impedance at it's lower frequency. I wonder if I could test to see if the impedance had shifted the crossover point by using an RTA? I can remeasure the coils on the old tweets that went with the xovers, but again, that isn't going to be very scientific either...
Shaun: It's centered at 2.5k, 12dB on the mids, and 18dB on the tweets. I can check this by covering up the tweeters--as the mids are in the doors and the tweets are in the rear deck.
One other thing I noticed last night: there's a fair amount of sibilance--not so bad that the Sss's hiss and crackle, but bad enough that they're really prominent with a little hiss. (Was listening to 'Blue' by Lucinda Williams--difficult track because her voice crackles and stuff anyway).
Shaun: It's centered at 2.5k, 12dB on the mids, and 18dB on the tweets. I can check this by covering up the tweeters--as the mids are in the doors and the tweets are in the rear deck.
One other thing I noticed last night: there's a fair amount of sibilance--not so bad that the Sss's hiss and crackle, but bad enough that they're really prominent with a little hiss. (Was listening to 'Blue' by Lucinda Williams--difficult track because her voice crackles and stuff anyway).
Hi DM,
The best you can probably do is measure the DC resistance of
the old tweeters and then match the new tweeters to this.
Fortunately your new tweeters are too sensitive to be used
"raw", so you should use an L-pad arrangement to reduce the
sensitivity to match the output output level of the midrange
and at the same time match the old tweeters DC resistance.
/Sreten.
The best you can probably do is measure the DC resistance of
the old tweeters and then match the new tweeters to this.
Fortunately your new tweeters are too sensitive to be used
"raw", so you should use an L-pad arrangement to reduce the
sensitivity to match the output output level of the midrange
and at the same time match the old tweeters DC resistance.
/Sreten.
Hi,
Thanks.
That's what I think I'm going to do.--match the impedance. The coil impedances weren't very far apart (less than 1 ohm)--so I'm not going to do anything untill I get an RTA to see what's really coming out of the tweeters.
Right now I'm trying to figure out if I should buy a Behringer RTA + mic for USD300, or a handheld for USD280, or a software program (freeware) with a mic and preamp for around USD140. I hate to go software if I'm still going to have a preamp that requires external power, so I'm really leaning towards the overkill solution of just buying the Behringer RTA, even though it's rackmount.
-derrick
Thanks.
That's what I think I'm going to do.--match the impedance. The coil impedances weren't very far apart (less than 1 ohm)--so I'm not going to do anything untill I get an RTA to see what's really coming out of the tweeters.
Right now I'm trying to figure out if I should buy a Behringer RTA + mic for USD300, or a handheld for USD280, or a software program (freeware) with a mic and preamp for around USD140. I hate to go software if I'm still going to have a preamp that requires external power, so I'm really leaning towards the overkill solution of just buying the Behringer RTA, even though it's rackmount.
-derrick
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