I have a pair of Usher spkrs which use the Vifa TC26TG05-06 tweeters. It's a 6 ohms 90db unit.
Out of vanity, I replaced it with a pair of XT25 ring radiator without changing the X-over. As the XT is 4 ohms and 91.5db, I expected higher high freq energy but, on the contrary, I'm hearing less.
How is this so?
Out of vanity, I replaced it with a pair of XT25 ring radiator without changing the X-over. As the XT is 4 ohms and 91.5db, I expected higher high freq energy but, on the contrary, I'm hearing less.
How is this so?
http://www.d-s-t.com/link/vifa/data/tc26tg05-06d.htm this site says your original tweeter has 92dB sensitivity.
If you look at the frequency response graphs of the tweeters (you can find them on madisound's site) you'll see that the FR measurements were taken at 2.83V @ 1m. 2.83V with an 8ohm speaker is 1W, but is 2W for a 4ohm speaker. If the XT25 were tested at 1W @ 1m you'd see that it would be less sensitive than your original tweeter. Some numbers by themselves can be misleading. Sensitivity is one of those numbers. Output power of an amplifier is a more infamous example
If you look at the frequency response graphs of the tweeters (you can find them on madisound's site) you'll see that the FR measurements were taken at 2.83V @ 1m. 2.83V with an 8ohm speaker is 1W, but is 2W for a 4ohm speaker. If the XT25 were tested at 1W @ 1m you'd see that it would be less sensitive than your original tweeter. Some numbers by themselves can be misleading. Sensitivity is one of those numbers. Output power of an amplifier is a more infamous example
hmmm...
Using the L-pad calculator from lalena and then plugging in the numbers into excel, I still couldn't quite understand what is happening.
With the woofer at 86db and the tweeter at 92db and assuming they only compensate it by 5db (I think they usually under compensate so that the speaker sounds brighter n more lively), I got R1 = 2.6 and R2 = 7.7.
Then I put these values with the 4ohms and I get a oervall imp of abt 5.2 ohms (close enough) and a reduction of 3.6db. Therefore the output shd be around 88db, right?
Yet somewhat the overall presentation is very muffled...
Using the L-pad calculator from lalena and then plugging in the numbers into excel, I still couldn't quite understand what is happening.
With the woofer at 86db and the tweeter at 92db and assuming they only compensate it by 5db (I think they usually under compensate so that the speaker sounds brighter n more lively), I got R1 = 2.6 and R2 = 7.7.
Then I put these values with the 4ohms and I get a oervall imp of abt 5.2 ohms (close enough) and a reduction of 3.6db. Therefore the output shd be around 88db, right?
Yet somewhat the overall presentation is very muffled...
Like I said earlier, the XT25 tweeter is 91.5dB with 2W@1m, not with 1W.
http://www.madisound.com/pdf/vifa/xt25tg30-04e.pdf
So it would be more like 88.5dB with 1W@1m, which is a lower sensitivity than you used with your calculations. You need to pad it down much less to bring the treble back up.
http://www.madisound.com/pdf/vifa/xt25tg30-04e.pdf
So it would be more like 88.5dB with 1W@1m, which is a lower sensitivity than you used with your calculations. You need to pad it down much less to bring the treble back up.
Hi,
Taipe - Taiwan.
We need your crossover freq.
Or more details, I don't know what we are dealing with. Your reference model of speaker, size and model of mid-woofer.
Do you have acess to x-over or not. Do you want to add that tweeter and not touching the insides. That is almost impossible unless you give it the same impedance. See, every x-over is made for only one speaker.
Best Regards.
Taipe - Taiwan.
We need your crossover freq.
Or more details, I don't know what we are dealing with. Your reference model of speaker, size and model of mid-woofer.
Do you have acess to x-over or not. Do you want to add that tweeter and not touching the insides. That is almost impossible unless you give it the same impedance. See, every x-over is made for only one speaker.
Best Regards.
Hi Inductor
1st thing 1st, I'm no taipei or taiwan. in fact those buggers juz called us 'stupid' in the media. anyway, our political leaders will settle that with them!
OK, let put things back perspective. I have no intention of changing the x-over. I have the XT25 and was experimenting with it and somehow couldn't recouncile the sound with the limited knowledge in speaker design. Like I said before, I thought of it too simply! I've reinstate everything as it just will not work!
However, your pics on the simulation is rather interesting. Is it from a freeware? I wld really love to play around with if to improve my understanding of spkr building!
1st thing 1st, I'm no taipei or taiwan. in fact those buggers juz called us 'stupid' in the media. anyway, our political leaders will settle that with them!
OK, let put things back perspective. I have no intention of changing the x-over. I have the XT25 and was experimenting with it and somehow couldn't recouncile the sound with the limited knowledge in speaker design. Like I said before, I thought of it too simply!
I've reinstate everything as it just will not work!However, your pics on the simulation is rather interesting. Is it from a freeware? I wld really love to play around with if to improve my understanding of spkr building!
Fossil said:
XT is sounding smoother but less density than TC26 maybe due to the wide high frequency range. Another important thing is: if you do not modify the x-over, then the frequency of high pass cut off frequency will a lot upper(in a case of -6dB/oct) than the original design because of the 4 ohm impedance of the XT and the Q value of the h-pass filter network will be dropped too low, which could made the tweeter sounding very wooden. The upper hi-pass roll-off add up low Q will cause a lack between mid and hi frequencies. So you maybe have to increase the value of the hi-pass cap, if x-over is -12dB or above, then the inductor value must be decrease at the same time. Try this step and find out.
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