Does anyone know the sensitivity specs of the factory installed tweeter? I would imagine quite high for lower power consumption...

Also, if anyone knows the crossover frequency of the tweeter it would be much appreciated...

I'm looking to replace the factory tweeter and seeking the most appropriate replacement. Mine seems harsh and fatiguing.


Thanks...

 

I thought the same thing about my tweets until I ran the fader all the way forward.

I will try next week to run a pink noise CD through the system and measure the tweeter wires with a spectrum analyzer to see the xover frequency (I don't have a spectrum analyzer, but I can get access to one sometimes). I'd like to do this with all the speakers.

Anyone have an impedance meter? At least you could find the impedance peak and thus the fS of the tweeter, which is a critical part of deciding what xover is needed...

 

I could take a look at the fs quite easily. Next week, I'll run it and let y'all know... I'm guessing the x-over point is still much higher than the fs though.

Has anyone added a passive x-over downstream of the amp and just preceding the Tweet to try and correct whatever funkiness is going on? All the S's and T's type of sounds are hissing... maybe just series inductance or a cap in parallel would kill it, but I've never tried it and I don't want to kill all the high frequencies.

I'll try the cap after i have an impedance curve and calculate something instead of guessing. Its difficult not knowing what the x-over internal to the amp looks like though.

Keep ya posted...

 

I could take a look at the fs quite easily. Next week, I'll run it and let y'all know... I'm guessing the x-over point is still much higher than the fs though.

Has anyone added a passive x-over downstream of the amp and just preceding the Tweet to try and correct whatever funkiness is going on? All the S's and T's type of sounds are hissing... maybe just series inductance or a cap in parallel would kill it, but I've never tried it and I don't want to kill all the high frequencies.

I'll try the cap after i have an impedance curve and calculate something instead of guessing. Its difficult not knowing what the x-over internal to the amp looks like though.

Keep ya posted...

 

Typically the rule of thumb is that the xover point must be at least 1 octave above Fs, and two octaves for max power handling (assuming a 2nd-order xover).

I personally use the one-octave rule with second order xovers when I build passives, and as long as plug in the actual measured impedance at my xover point instead of what it says on the sticker, I've had almost zero tweeter failures. Just don't have an impedance meter any more.

Anybody selling a Rockford IM-1?

 

Just out of curiosity, is this happening with all sources?

 

elduderino, are you asking if the ugly sound mentioned previously (hissing) is happening with all sources? Or were you refering to something else?

 

[QUOTE=Castles_Saloon]elduderino, are you asking if the ugly sound mentioned previously (hissing) is happening with all sources? [QUOTE]

Yes.

 

Since I couldn't figure out how to insert a pdf as an image, you can email me at macjunk@hotmail.com if you want the actual z curve.

If any one could enlighten me as to the best way to post a pdf is, then please do so and i'll gladly post the z-curve.

Sorry for the technical difficulties...

 

The curve is less relevant to me than the Fs and how steep it is (i.e., what's Zmax, and would you describe the peak as narrow or wide?)

They look like OK tweeters... but I'm replacing them anyway.

 

The impedance curve is surprisingly flat. Z min = 3.25 ohms; Z fs = 3.9 ohms; dips back down to 3.25 ohms at 5kHz and rises with to 3.9 ohms @ 20kHz.

The peak is not much of a peak, but if you used 70% of Z max, the frequency bounds would be 1200 & 1700 Hz.

Note: when I drove the tweet with an absolutely pure sine wave of 500 hz (Fluke 57000 Calibrator), there were many other frequencies you could hear. Perhaps harmonics or just ugly resonanes of the tweet, but they were there. Its seems best to invest in new tweets...

 

Hey guys. Im not sure exactly what all your technical terms mean, but my tweeters sound like crap as well. Happens on songs you wouldnt expect tweet distotion on at all like The Doors and DMB.

 

In reading your post, I think the actual frequency of the impedance peak got left out? You seem to be saying that there's an incredibly low Q to the peak's shape. From what you said later in the post, it sounds like your measured maximum impedance occurred at 1450 Hz.

However, to have such a low impedance peak, these things must be stuffed with ferrofluid. Or something.

If you drive a dynamic transducer with a test tone one octave below its resonant frequency, is it going to sound good? I'm not sure, but my inclination is to suspect that dynamic drivers don't perform far below their resonant frequency in a linear fashion. Maybe I'm totally wrong... but back in the 80's, whenever I tried to get bass out of customers' 15" EV PA woofer speakers, that were really midranges with Fs up in the high hundreds, it never worked. I would think a tweeter isn't going to play 500 Hz well, and that it's not designed to...? If it has an Fs of 1450, I would send a test tone of 2.9K-3K through it and see how it sounds - that's where I would expect it to be designed to perform.

If the crossover on this tweeter is one octave above your measured Fs (a standard rule of thumb with second-order networks to keep tweeters from blowing up), it's -3dB point is at 2.9K. If it's a second-order network, then the tweeter would be -15dB down at 1450 Hz (-3 + -12 = -15). It would then be -12dB more at 775 Hz, and -4dB more (approximately) at 500 Hz.

So with these assumptions, this tweeter is playing 500 Hz at -31dB down! It's important to have good linear perfomance in the stopband, but I don't know that I'd worry much about stuff happening 31dB down.

All this assumes that the tweeter is crossed over one octave above its resonant frequency (could be two octaves and 5K, depending on the school of thought of the speaker system designer), that the measurement showed the impedance peak at 1450 (just an extrapolation on my part at this point) and that the crossover is second order (an assumption - it's possible that the tweeters are in parallel with the F door mid channels and just have a first order series capacitor for a 6dB/octave slope - at which point its inability to play 500 Hz could become a huge shortcoming.)

So, why are you willing to change the tweets but not swap out the amp?

 

yeah, I hope you are certainly right about the crossover being somewhere in the ~3kHz ballpark. I only mentioned the obvious breakups I noticed when first firing up the tweet at 500 Hz. The only thing I wondered is if their were any correlations in sonic errors at 500 Hz vs. a higher f's. For tones at 2khz and greater, i didn't listen for any misbehavior. This was a really quick bench test (20 min. for soldering testing, recording and all) so I could have easily made a mistake. I'll double check it and let ya'll know if I find a mistake.

You're right about the Q being abnormally low... I noticed that too which gave me second thoughts as to the correctness of my test. But the Fs = 1450 Hz sounded right. A Z changing from just above 3 ohms to 4 is almost too small of a variation. My excel sheet was probably hosed or sumthin'.

As far as looking at the tweets vs. new amp, etc., its simply a cost thing. How can I get the most bang for the buck? Tweak the existing amp, swap out Tweets, these are all under $100. To get a decent Amp is ~$500. Just as JonPfive also mentioned, the tweets sounded like crap, so I'm starting with the tweets and working my way backwards. God I just hope its not the source(CD) or pre-amp. Then we're all limited as too what improvements new speakers or amps can provide.

How much improvement in SQ have other members noticed from their upgrades? I presume its quite siginificant which gives me confidence in amp or speaker changes...

 

If you have added an auxillary input to your tsx, how would you compare the SQ of the new source (i.e. IPOD) vs the existing cd player?

Assuming the lowest level of compression for MP3s, etc. like 320kb...

if the harshness of the highs/Tweets is still equal to that of the CD when played through the MP3 player, then the problem is downstream (amp, x-over, speakers). Otherwise, the source of our woes is actually the CD player/DAC or pre-amp.

Has anyone done some true SQ comparison of a single track on the CD player vs. MP3 player (least compresstion)?

Maybe I just need to add an auxillary source... hmmm

 

You know, Castle, I thought the tweets sounded awful until I faded my system all the way forward. The sound smoothed out a LOT - even my fiancee noticed. I suspect the rear mids are running wild at the high end and playing lots of crud... give it a try.

I'm still gonna upgrade, but in the meantime...

 

Thanks elduderino for the tip! That does make a lot of sense to me...

Do you know the kind of cone material the stock speakers are? If the rear doors are playing all frequencies, then they could easily be the cause of the harshness and high frequency distortion. You may have just saved me some money... at least for the time being

 

I think they are just shiny treated paper... haven't seen the rears in person, but there are photos here in the sticky about pulling door panels...

Let us know...

 

I tried fading to the front. That did smooth out some of the harshness I was hearing, but it wasn't a total cure. Its time for me to start saving some $$$ for replacement speaks, amp, and auxillary input...

Has anyone tried to fit Boston z6s in the front doors? If so, what did you think of the SQ in the TSX and what custom speaker mounting did you use?

 

To get more responses, I would post that question in a new thread...