So I modeled a 4th order in hornresp and it had a 15 db honk at the low end of its pass band. I've only one vent is there another way to rduce said vent?
Is it perhaps due to box resonance lining up with driver resonance? It's right around the fs of the driver.
Is it perhaps due to box resonance lining up with driver resonance? It's right around the fs of the driver.
So if I want to help you I have to look up the parameters and sim it myself? Why don't you post some screenshots of your results so a guy has a fighting chance to answer your question? perhaps you did something silly, perhaps you have tuned too high or too low.... play around...
i wouldnt trust factory specs for the driver, better to test them yourself given Pyle's quality control. going out on an uneducated limb, methinks the only way to try to get extension out of that driver is going to be a healthy sized ported box with a steep high pass filter.
You'll have to provide a bit more information on what you're doing. What are the dimensions of the box and what driver specifically are you using?
Pyle doesn't give full sets of t/s params so you'll have to make educated guesses for some of them.
Pyle doesn't give full sets of t/s params so you'll have to make educated guesses for some of them.
Let's see what I can muster.
In general...given a 4th 9rder or sealed enclosure if the driver resonance and the enclosure resonance are similar will there be a large spike?
In general...given a 4th 9rder or sealed enclosure if the driver resonance and the enclosure resonance are similar will there be a large spike?
If you want a symmetrical response, you want to tune the vented enclosure of a 4th order bandpass to whatever the resonant frequency of the closed box is, not to the free air resonant frequency of the driver.
eg, if you have a driver in a box 1/3 the size of Vas, you tune to twice free air resonance....
Fb=Fs*sqrt(Vas/Vb+1)
Very old WT3 measurements [3.3.11], so YMMV:
Fs: 27 Hz
Re: 7.8
Qts: 0.66
Qes: 0.89
Qms: 2.6
Le: 3.3 mH @ 1 kHz
Vas: 27 cubic feet
Mms: 150 gr.
At best, it will have a 'ringing' response without significant damping and since these specs are 'world's apart' from published plus some others, each driver really needs to be measured unless a super huge cab is planned.
'Quickie' BP4 sim attached.
GM
Fs: 27 Hz
Re: 7.8
Qts: 0.66
Qes: 0.89
Qms: 2.6
Le: 3.3 mH @ 1 kHz
Vas: 27 cubic feet
Mms: 150 gr.
At best, it will have a 'ringing' response without significant damping and since these specs are 'world's apart' from published plus some others, each driver really needs to be measured unless a super huge cab is planned.
'Quickie' BP4 sim attached.
GM
Thx for the input...yes I'll be using it in a van so there perhaps 40 -100 cu ft.
I'll probably get a set of measurements on the drivers I order.
Just in case your wondering I'm only using the 21s because nobody else does.
I'll probably get a set of measurements on the drivers I order.
Just in case your wondering I'm only using the 21s because nobody else does.
Understood, I was looking at these recently for a lossy sealed + digital EQ to shape its response, Qtc.
GM
GM
AKA ~aperiodic loading to acoustically resistive load the speaker to a lower effective Qtc than if sealed, i.e. basically a highly damped reflex.
GM
GM
This method is opposite of "modern" box-building technology. The idea behind lossy sealed enclosures is to use a thin-wall, acoustically damped enclosure. This is a pie in the face to the common DIY practice of building enormous, super-stiff enclosures that try to act like an airtight concrete box. The flexing of the enclosure is exploited and tuned much like that of an acoustic instrument, only in this case the low frequency content is maximized. The whole subject is tricky and subjective in nature.
Take a gander at this thread to see what I mean:
http://www.diyaudio.com/forums/mult...-i-found-lossy-cabinet-designs-harbeth-2.html
I would say that combining this method with a bandpass enclosure would be like looking through a telescope, through a microscope, through a periscope to see straight ahead around a corner. Good luck with that.
Take a gander at this thread to see what I mean:
http://www.diyaudio.com/forums/mult...-i-found-lossy-cabinet-designs-harbeth-2.html
I would say that combining this method with a bandpass enclosure would be like looking through a telescope, through a microscope, through a periscope to see straight ahead around a corner. Good luck with that.
Last edited:
??? No biggie, just controlling the rear chamber's Qtc via a highly damped vent, with super high Qt typically requiring both cab and vent to be stuffed; for sure don't do the flimsy cab type ~aperiodic alignment if a BP.
GM
GM
- Status
- Not open for further replies.