Could easily be some room interaction or ground-bounce.
Regarding driver distortion (amo's question):
I have some JBL 1" drivers that have around 1 % THD for 1 Watt of input power. If you look at it just like that, one is tempted to think that this quite much THD for such low power. If you have a 2nd look then you'll see that it will generate more SPL than an average dome tweeter shortly before it's voice-coil is melting. At reasonable listening levels THD is much lower than the average dome tweeter will ever achieve. And I must say that there are better compression drivers out there than my JBLs. Lower THD than good horn drivers is only achieved by some high-power ribbons like the SA driver.
Regards
Charles
The dips down at ~100Hz and ~380Hz vary with mic. position, and look last picture here http://home.tu-clausthal.de/~tpa/port/index.html the 100Hz one is there measured at same position with completely different speaker (150mm sealed enclosure compound isophon) Must be some room interaction there.
Its possible to supress the peak at 200 to 280 Hz somewhat, i don´t really know if its better in sound now:
Its possible to supress the peak at 200 to 280 Hz somewhat, i don´t really know if its better in sound now:
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crossover parts count climbing, weight of crossover component reaches the weight of other peoples speakers....
I more and more have the feeling more components are fighting room response and not speaker response anymore, as measurement position does the most differences on cuves.
I more and more have the feeling more components are fighting room response and not speaker response anymore, as measurement position does the most differences on cuves.
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could i please have some guidance by crossover experts? is that crossover totally nonsense?
The tweeter impedance in crossover region is about straight 8 Ohms. The bass goes from 8 Ohm at ~300Hz up to ~ 14Ohm at 1000Hz.
So what was intended for linkwitz riley 540Hz is more like LR 540Hz for the tweeter and maybe 540Hz Butterworth for the bass. should i use at the bass something like 6.4mh 13.4uF instead?
The tweeter impedance in crossover region is about straight 8 Ohms. The bass goes from 8 Ohm at ~300Hz up to ~ 14Ohm at 1000Hz.
So what was intended for linkwitz riley 540Hz is more like LR 540Hz for the tweeter and maybe 540Hz Butterworth for the bass. should i use at the bass something like 6.4mh 13.4uF instead?
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Measurements
till,
Your doing and learning some really great stuff. Before your can really rely on your measurements, you need to be able to know what's your speaker and what's the room. Can you see the comb filtering in the early graphs? The log freq scale makes the combs look closer in the hi end, a lin scale would look like an evenly spaced comb.
Do you understand hancocks post? Don't "fix"room problems in your crossover.
Know this, even the early graphs are very nice! You should ignore what are clearly room distortions. Can you look at phase with hobbybox? Perhaps take a look at http://www.sat-live.com/
Then you will be able to see phase and measure with music, not noise.
till,
Your doing and learning some really great stuff. Before your can really rely on your measurements, you need to be able to know what's your speaker and what's the room. Can you see the comb filtering in the early graphs? The log freq scale makes the combs look closer in the hi end, a lin scale would look like an evenly spaced comb.
Do you understand hancocks post? Don't "fix"room problems in your crossover.
Know this, even the early graphs are very nice! You should ignore what are clearly room distortions. Can you look at phase with hobbybox? Perhaps take a look at http://www.sat-live.com/
Then you will be able to see phase and measure with music, not noise.
Till: Is it alot of work for you to make the transition piece between wooden horn and driver (the aluminium looking piece)? I'm making wooden horns for a TAD 4001, and would love to pay you some euro cash to make me a pair of these metal pieces.. It would be about double the size as yours...
do you have material / round piece of metal for this? The material is not really cheap if you have to order the normal way. I would need to drive on day to a friends workshop, who has all the tools and i can work there without paying money for using the metalwork tools.
Are there still drivers without diaphragms?
Are there still drivers without diaphragms?
I do not have metal for it, no. I assume you use aluminium? Any idea where i'll get thick metal rods cut to custom lengths?till said:
You don't have to go through all that if you do not have tools for the job yourself. It'll probably be cheaper, quicker, and easier to do this locally i guess. Just contacted slowmotion regarding this, as he lives in Norway and I think he metioned once he had a suitable tool for such a job. If using aluminium I can probably do this on a lathe designed for woodworking too?
The diaphragms are soon to be on their way (Radians)
Thanks for sharing your excellent project.
"If using aluminium I can probably do this on a lathe designed for woodworking too?"
no.
You need a serios metal lathe to do this right. We have a precision one (at my friends place) for about 1000mm long and 420 mm diameter pieces.
I can order the aluminium, but do not expect it to be cheap. I can ask prices, but you need to send me a drawing first. Please email.
For the drivers i want to know if there are still some TD4001 for sale for good price.
no.
You need a serios metal lathe to do this right. We have a precision one (at my friends place) for about 1000mm long and 420 mm diameter pieces.
I can order the aluminium, but do not expect it to be cheap. I can ask prices, but you need to send me a drawing first. Please email.
For the drivers i want to know if there are still some TD4001 for sale for good price.
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