Hi Pelanj
Too small… yes maybe, that’s why I wrote, that I will start small 😉
The are roughly 3cm * 1cm each.
SD of the driver is 55cm², my ports have ~6cm² what is not so far away from recomandation, or is my calculation wrong?
And: what I think to know is, that the distance to the diafragma should be max. 1/4 of wavelength of highest frequency… less is no problem. Is this wrong?
If I would use same frequency range but smaller driver, ports can be small… why not, if I have a larger driver? What are the disadvantages?
Will try to have them as small as possible to make sure, that I don‘t get problems (reflections in the horn) with the tweeter.
To close to the throat (dia)… maybe, the farest point is ~14cm. so i could move them maybe another 3 cm
Christian
Too small… yes maybe, that’s why I wrote, that I will start small 😉
The are roughly 3cm * 1cm each.
SD of the driver is 55cm², my ports have ~6cm² what is not so far away from recomandation, or is my calculation wrong?
And: what I think to know is, that the distance to the diafragma should be max. 1/4 of wavelength of highest frequency… less is no problem. Is this wrong?
If I would use same frequency range but smaller driver, ports can be small… why not, if I have a larger driver? What are the disadvantages?
Will try to have them as small as possible to make sure, that I don‘t get problems (reflections in the horn) with the tweeter.
To close to the throat (dia)… maybe, the farest point is ~14cm. so i could move them maybe another 3 cm
Christian
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I was confused by the 12" dimension of the woofer - these have usually Sd of around 500 cm2 - and the holes looked (visuaĺy) like less than 1/10 of the Sd. The important distance is along the centerline of the horn. Placing the ports is a balance between highest frequency required and amount of interference with the HF. I am not sure how that would really work in the narow slot you have. If the slots are unnecessarily too close, weird stuff happens. Less than 1/4 wavelength is great, much less than does more harm than good. How much less I cannot tell. If the woofers can play high, you can increase the crossover point easily to see the influence.
Now you should See the Misstake. The Sd of the beyma ist 550cm2 not 55cm2.
So your holes are much too small at the moment.
So your holes are much too small at the moment.
Ahhhh…
Yes… crazy… just factor 10 😉
And welcome back to the 4“ Driver 😉
But i still have no idea, why the size of the holes depends on size of the driver and not on frequency and spl.
Is there anybody who could explain that?
Thx… especially for the hint… still unbelievable, that I made such a mistake 😉
Christian
Yes… crazy… just factor 10 😉
And welcome back to the 4“ Driver 😉
But i still have no idea, why the size of the holes depends on size of the driver and not on frequency and spl.
Is there anybody who could explain that?
Thx… especially for the hint… still unbelievable, that I made such a mistake 😉
Christian
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The size of the Ports depents on different Things. It's a bp4 so the size of the Camber (place in Front off the Driver) is different to smaller drivers. So the bp4 Port Changes it's size or lengh.
OK... something what need to be accepted 😉
But it would be a little bit better, if i would reduce the chamber in front of the driver?
Anyway: will change back to the already advised B&C 4NDF34-16 and will use 4 of them.
Thx a lot for the help and the hint!
But it would be a little bit better, if i would reduce the chamber in front of the driver?
Anyway: will change back to the already advised B&C 4NDF34-16 and will use 4 of them.
Thx a lot for the help and the hint!
Moin 😉
I have ordered 8 of the 16 Ohm version. This way I can drive the 4 in parallel and don‘t need to make a seriell/parallel mix.
Will try to drive them down to 100Hz… because i don’t need heavy SPL and will use sharp crossover, it could work.
Update will come as soon as possible… hopefully the drivers will arrive mid of next week, so let’s hope for next weekend 😉
Christian
I have ordered 8 of the 16 Ohm version. This way I can drive the 4 in parallel and don‘t need to make a seriell/parallel mix.
Will try to drive them down to 100Hz… because i don’t need heavy SPL and will use sharp crossover, it could work.
Update will come as soon as possible… hopefully the drivers will arrive mid of next week, so let’s hope for next weekend 😉
Christian
Hi Josef
Another question: what Port size have you used?
Thx
Christian
Better then the 16 Ohm? If why?
Another question: what Port size have you used?
Thx
Christian
My First Prototyp used two 1,6cm holes that equals 4cm2 with lengh of 2 cm. They we're good from 125hz to about 1 kHz
The 8 Ohm have more Clean Output capacity.
The 8 Ohm have more Clean Output capacity.
Thx!
I will make the holes a bit larger to get something between 4-5cm2
What do you mean by „more clean output capacity“? In my experience it’s better to have drivers in parallel instead of in series… so hopefully same here 😉
At the end, it will be a complete active system with DSP and FIR filter.
I will make the holes a bit larger to get something between 4-5cm2
What do you mean by „more clean output capacity“? In my experience it’s better to have drivers in parallel instead of in series… so hopefully same here 😉
At the end, it will be a complete active system with DSP and FIR filter.
8 to 16 Ohm FS is Higher and xmax is the half
the 16 Ohm is OEM it's hard to get the right Datasheet.
the 16 Ohm is OEM it's hard to get the right Datasheet.
Uhhh…
Will try to change the order… but because ordered by express I am not optimistic. Let’s hope.
Will try to change the order… but because ordered by express I am not optimistic. Let’s hope.
Mmhhh..
In the specs I found, x-mal is a little bit higher in 16 Ohm version… fs: yes, definitely lower at 8 Ohm ;(
https://en.toutlehautparleur.com/media/catalog/product/datasheet/bc/4NDF34-8.pdf
https://en.toutlehautparleur.com/media/catalog/product/datasheet/bc/4NDF34-16.pdf
In the specs I found, x-mal is a little bit higher in 16 Ohm version… fs: yes, definitely lower at 8 Ohm ;(
https://en.toutlehautparleur.com/media/catalog/product/datasheet/bc/4NDF34-8.pdf
https://en.toutlehautparleur.com/media/catalog/product/datasheet/bc/4NDF34-16.pdf
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I made a simulation in AJ-Horn. I know, it can not simulate meh's but mabe it is a good starting point for bass behavior.
To me it seems, that 16 Ohm behaves a little bit better than 8 Ohm... is this wrong?
16 Ohm:
8 Ohm:
Used TSP:
To me it seems, that 16 Ohm behaves a little bit better than 8 Ohm... is this wrong?
16 Ohm:
8 Ohm:
Used TSP:
Hi, have you tested both, the 8 and 16Ohm ?
If so, please say how tested..
I've always thought the specs for the 16 ohm on tlhp looked a bit bogus compared to the 8 ohm.
B&C doesn't list 16 ohm specs that I can find....nor does anyone besides TLHP...
Also have to say 4mm xmax seems a bit crazed just looking at the driver suspension....
So really curious how you came about 2.4.
Yes i have both here. 2.4 seams right. i can get the right datasheet if you like.
The 8 Ohm Variant has an xvar of 5.7 and that controlled. The 16 ohm xvar of 3mm
but you can also calculate xmax from winding and magnet gab
i think looking at half the xvar 6 db less is possible
The 8 Ohm Variant has an xvar of 5.7 and that controlled. The 16 ohm xvar of 3mm
but you can also calculate xmax from winding and magnet gab
i think looking at half the xvar 6 db less is possible