First of all, I would say that the design I want to achieve is based on the project made by Dark Regent.
Peerless Push-Pull Build Thread (with pics)
I am writing in this forum to ask for some help with the simulation of different programs such as bass probox pro, WinISD or LspCad (I have these three programs but I dont know how to design these special cabinets on them )
The woofers I will use will be these peerless
Peerless XLS 830452
a) how can I know the total volume of the box?
b) how can I know all the sizes of the box?
P.D: I dont want to spend more money on divers, I think these peerless are good enough. I am not worried about the final Qtc, I am just interested on the nice dipolar sound of the box ( non lineariteis in the response will be corrected through an equalizer).
Peerless Push-Pull Build Thread (with pics)
I am writing in this forum to ask for some help with the simulation of different programs such as bass probox pro, WinISD or LspCad (I have these three programs but I dont know how to design these special cabinets on them )
The woofers I will use will be these peerless
Peerless XLS 830452
a) how can I know the total volume of the box?
b) how can I know all the sizes of the box?
P.D: I dont want to spend more money on divers, I think these peerless are good enough. I am not worried about the final Qtc, I am just interested on the nice dipolar sound of the box ( non lineariteis in the response will be corrected through an equalizer).
I haven´t found them on ebay. By the way, where to buy those drivers is not my main problem... I just want to know how to build the cabinet...
Push Pull designs just have two drivers in one enclosure. You would just model it as a sealed box in winusd but with 2 drivers.
The design in the thread that you linked to seems to have a bit of a port behind the second driver although they didn't seem to model it. Its quite hard to modeL that, though I think you can do it in hornresp.
The design in the thread that you linked to seems to have a bit of a port behind the second driver although they didn't seem to model it. Its quite hard to modeL that, though I think you can do it in hornresp.
That little port thingy behind the second driver imo, is just their way of managing to make a reverse mounted driver fit in without looking like a mess. I'd imagine you'd get a cavity resonance appearing of the quarter wave variety because of it. My guess is that this would probably be higher up then the normal range the sub would be called on to reproduce so would be effectively removed by the usual low pass. Of course measuring just in front of the mouth would show you exactly what it does.
I have modeled these two drivers into a sealed box, I got the fs frequency and I checked that the cone excursion is always below the maximum value.
My question is, how far results can be from the box I will develope, because the cabinet I will develope is not a sealed box, it has two "ports" below the second driver.
My question is, how far results can be from the box I will develope, because the cabinet I will develope is not a sealed box, it has two "ports" below the second driver.
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WinISD can do two drivers in a ported box. Turning one around backwards makes no difference to the box. But, that looks like a sealed box. The big opening in the bottom is not a port for tuning, it is just the exit for the lower driver. So, the box is twice as big as a box for one driver. Simple as that.
ok so, I just have to model my design as a two drivers into a closed box to find out which is the optimal box ( depending on fs, qtc and cone excursion parameters)..
After calculating the sizes of the box, how can I calculate, how big the "big opnenings" in the bottom are? and how high the second driver is placed? I guess that depending where I place the second driver it will influence the final result.
After calculating the sizes of the box, how can I calculate, how big the "big opnenings" in the bottom are? and how high the second driver is placed? I guess that depending where I place the second driver it will influence the final result.
Here, there is a picture of the results achieved in the simulation... Transfer function, cone excursion and impedance for a two drivers sealed box powered with 100W.
An externally hosted image should be here but it was not working when we last tested it.
Previous images were taken from WinISD
BassBox Pro
Results are pretty similar in cone excursion and SPL but, impedances show two different fs...
These are my questions after comparing the graphs:
a) Is it true that these drivers cant handle frequencies below the frequency which makes impedance maximum?
b) Which is the minimum frequency my simulated boxes could play¿?
c) do these parameters depend on the shape of the box? I mean, will these parameters ( impedance, SPL, cone excursion ) change depending on the shape of the box? I wont build sealed boxes... I will build these special push pull subwoofers cabinet.
BassBox Pro
An externally hosted image should be here but it was not working when we last tested it.
Results are pretty similar in cone excursion and SPL but, impedances show two different fs...
These are my questions after comparing the graphs:
a) Is it true that these drivers cant handle frequencies below the frequency which makes impedance maximum?
b) Which is the minimum frequency my simulated boxes could play¿?
c) do these parameters depend on the shape of the box? I mean, will these parameters ( impedance, SPL, cone excursion ) change depending on the shape of the box? I wont build sealed boxes... I will build these special push pull subwoofers cabinet.
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They are on ebay UK right now, the reason I mention it is that they are half the Wilmslow price, I just bought a pair.
I have already seen the loudspeakers on ebay but, T-S parameters are completely different. It seems to be the same driver, with the same reference name and everything, but the parameters are different.
Take a look to the comparision picture I made...
An externally hosted image should be here but it was not working when we last tested it.
How is possible so different parameters in the "same" model? It is just an ebay mistake or is it possible these differences?¿
ebay Peerless XLS10 P830452
Wilmslow Peerless XLS 830452
Maybe the P before the "830452" means that these are different from the others...
you are right... tymphany show the same parameters than ebay.
Is Wilsmlow parameters fake or is it a different driver?¿
I have opened a new thread for not contaminating this thread.
http://www.diyaudio.com/forums/subw...tures-peerles-xls10-830452-a.html#post3196235
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Drivers do go through different versions without the part numbers changing. The two 452s are still pretty similar but do show some small differences.
Both sets of parameters are correct, now as to which parameters belong to your driver? That's up for you and the supplier of you drivers to decide. An email to Tymphany wouldn't hurt.
No.
As low as you want. What determines how loud the sub will play for a given frequency is it's rated xmax and power handling.
Yes, but not enough to be significant in this case.
There's nothing special about a push-pull driver arrangement, what you're building is a sealed box.
Both sets of parameters are correct, now as to which parameters belong to your driver? That's up for you and the supplier of you drivers to decide. An email to Tymphany wouldn't hurt.
No.
As low as you want. What determines how loud the sub will play for a given frequency is it's rated xmax and power handling.
Yes, but not enough to be significant in this case.
There's nothing special about a push-pull driver arrangement, what you're building is a sealed box.
I want to build this PUsh Pull subwoofer.
I will be using the Scanspeak 30wT4558 driver which has almost the same
T&S like the peerless 830517 (xxls12)
I will be using the Scanspeak 30wT4558 driver which has almost the same
T&S like the peerless 830517 (xxls12)
Volume of box.
Sim is a starting point. Prototype.
Of course drivers can "handle" below their impedance peak. How much is the question.
Sim is a starting point. Prototype.
Of course drivers can "handle" below their impedance peak. How much is the question.
these drivers look amazing asdonk... just remember that you will need an amplifier capable of driving 2 ohms... ( since your speakers are 4ohms each )
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