Hey folks.
Long time lurker of the great minds here. I purchased some inexpensive PA mids (PRV 10W650A-4) and wanted to fiddle around with a BIB style enclosure. Future plans aside, I just realized that the dust cap is mesh and the speaker has a vented pole piece. From my perspective, that sounds troublesome. I don't necessarily see that being a problem in a vented or BIB enclosure (maybe) but does anyone have experience with a speaker that has these characteristics and what to expect?
My first thought was a phase plug since but I also don't have measuring software and don't feel like paying for the shipping (Guam.)
Any inputs is appreciated.
Long time lurker of the great minds here. I purchased some inexpensive PA mids (PRV 10W650A-4) and wanted to fiddle around with a BIB style enclosure. Future plans aside, I just realized that the dust cap is mesh and the speaker has a vented pole piece. From my perspective, that sounds troublesome. I don't necessarily see that being a problem in a vented or BIB enclosure (maybe) but does anyone have experience with a speaker that has these characteristics and what to expect?
My first thought was a phase plug since but I also don't have measuring software and don't feel like paying for the shipping (Guam.)
Any inputs is appreciated.
@Freedom666
That was my thought process, especially since they won't be seeing rated power any time soon, so cooling wasn't going to be an issue.
That was my thought process, especially since they won't be seeing rated power any time soon, so cooling wasn't going to be an issue.
What is a BIB? Box in box? And why wouldn't the cloth dust cap and vented pole be less of an issue in a vented enclosure? There's just as much internal pressures involved as any other enclosed system, actually very high at tuning frequency.
Not familar with PRV products. But it might have been done on purpose for others the 'weight savings' as PRV states.
I notice the driver has a very unordinary and thick spider.
Also when you have a vented pole piece. No frame/under spider vents, no voice coil venting i assume?
The driver might show some cavity resonances, that negatively affects the performance, if you plug the dustcap mesh.
Just something to be aware of.
From my understanding, around tuning frequency, output from the port wouldn't be affected by the small hole created by the pole vent and mesh dust cap
(My) Altec 515B with small vented mesh insert with 3" VC = ~1437 Hz and its 'shouty' + 6 dB, relatively benign decay HF response Vs the PR's 2.5"/1724 Hz dual? vent(s) ~ +7 dB 'ringing' decay over an octave's wider BW in comparison and at these BWs/acoustic power they're transparent to any LF box alignment.
FWIW I've tried adding up to a 5 kHz (super) tweeter (horns) with good results for the men, the women not so much with the higher XO points, but not sure I'd want to spend the time trying it with the PRV beyond ~2 kHz.
This seems like high efficiency mid bass.
Fs is closer to 67 / 68 Hz
Any vented alignment would be tuned way above the leakage of
the voice coil cooling passage which would be way below 20Hz
Quick glance at mechanical properties.
Likely a large box or .5 Q wont be much larger than
35 to 45 liters or close to Vas
In a basic speaker model leakage or Ql would not
need to much lower than standard Ql of 7
modeling a 40 liter box
So extreme case model with Ql of 5
and compare to model with Ql of 7
to see the absolute amount of change.
Likely possible from real world voice coil leakage.
meaning even with exaggerated model
effect very little in 40 liters
Fs is closer to 67 / 68 Hz
Any vented alignment would be tuned way above the leakage of
the voice coil cooling passage which would be way below 20Hz
Quick glance at mechanical properties.
Likely a large box or .5 Q wont be much larger than
35 to 45 liters or close to Vas
In a basic speaker model leakage or Ql would not
need to much lower than standard Ql of 7
modeling a 40 liter box
So extreme case model with Ql of 5
and compare to model with Ql of 7
to see the absolute amount of change.
Likely possible from real world voice coil leakage.
meaning even with exaggerated model
effect very little in 40 liters
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A breathable/mesh dustcap is a small cover that is placed over the speaker cone of a speaker system to protect it from dust and other particles. Unlike traditional dustcaps made of solid materials like plastic or paper, a breathable/mesh dustcap is made of a porous material that allows air to flow through it, improving the speaker's performance and reducing the risk of damage from dust accumulation. This design also enhances the overall sound quality of the speaker system by allowing for improved airflow and reducing unwanted vibrations.
I'd have to disagree with that. If there's actually a hole through the pole piece and a mesh dust cap, that's going to be an issue for that driver in any enclosure.
At the tuning frequency the acoustic loading is the greatest, hence why the speaker cone excursion is low.
I test speakers all the time that have small holes put in them by removed mounting brackets. Those little holes make the most noise the closer you get to the tuning frequency. I get that a lot of people think that big hole in a vented box is just that, a big hole. It is when the speaker is just sitting there, but not when it's being played.
I understand the concept, but the discussion is just normal vented
coil.
There is hundreds of examples of enclosures using vented coil speakers.
and the impedance curves always just show good old normal reflex.
not much different than a speaker with phase plug.
all cones, cloth surrounds, coil vents have leakage.
better not to overthink. or tinker
drop it in a sim, you use plain jane 3rd or 4th order alignment.
life goes on.
unless 50 to 60 years of basic vented coils were all just
wild guesses.
Even with basic old paper cardboard coils, many dust
cap were just thin felt. All worked fine
coil.
There is hundreds of examples of enclosures using vented coil speakers.
and the impedance curves always just show good old normal reflex.
not much different than a speaker with phase plug.
all cones, cloth surrounds, coil vents have leakage.
better not to overthink. or tinker
drop it in a sim, you use plain jane 3rd or 4th order alignment.
life goes on.
unless 50 to 60 years of basic vented coils were all just
wild guesses.
Even with basic old paper cardboard coils, many dust
cap were just thin felt. All worked fine