no, its pointless
box will be a 'deadzone'
none, or very little output from port
and the dipole effect will even outphase bass output from outside facing cones
theres several 'sides' of pushpull, or the various driver mounting
mounting two woofer opposite each other, one on either side, or back/front, is usually to try and 'null' mechanical ressonances
usually push/push
push/pull mounting woofers is usually done to try and equal out the difference of drivers moving either in or out
the difference is caused by different electrical situations in magnet gap
and also mechanical difference in suspencion design
some will be worse than others
push/pull means two woofers, with one mounted 'normal', and other mounted reversed, magnet pointing out
to make cones move the same, drivers are electrically phase reversed
then you have isobaric 'clamshell'
a search will easier explain this
in my opinion the only true push/pull
I have never heard it, but they say a driver can make noises from its venting system, on backside
might be heard through the port
but only on very large excursion, I suppose
port noise I suppose is a different aspect, related to how the port itself is designed
I guess the rounding of port edges is one aspect of this
could be that none of the above is the absolute truth
lots of non proven facts and theories around
some may be audible, some not
depends on lots of other sides of each design, and the whole setup
how its used, etc
and I prefer closed box
No, .75 cubic feet will need be enough. You won't even have enough volume to fit a port in.
I would think 2 cubic feet per sub is a good estimate.....I didn't have time to model it last night, but I will soon enuff.
Ok. got it. Now only one woofer per box in about 1.8 Cuft tuned to about 33-35 Hz. Its rated 200 watts Rms so with 4 i would have 800 watts to spare, intend to runt them crossed over LPF of 60-80 Hz in series (making Dc resistance 2.7 ohmx2 )=5.4 ohm running off Peavey PV 2600 with built in 40 Hz Subsonic filter.
For LFE effect i am planning to use a 12 inch LVS driver used in Wilson Watch dog subwoofer. i emailed to confirm specs and they suggested either 3.6 Cu ft tuned to 35 Hz for music or if its only for LFE then tunning at 25 Hz in a 4.7 Cu ft encolure. It would be crossed over below 44-50 Hz.
I suupose i cannot use the 10 inch quatro for extreme low frequency. any thing below 40 Hz would need too much displacement and would induce distortion. thats why 4 drivers come into play .
One thing on my mind is that why to bother too much , its Fs=38 Hz with sealed 1.5 cu Feet enclosure i may get around 44 Hz FB or pull push in sealed 1.8 would give Fb=48 Hz. Just wondering if thats too high ??? Any idea for shooting it as well ????
For LFE effect i am planning to use a 12 inch LVS driver used in Wilson Watch dog subwoofer. i emailed to confirm specs and they suggested either 3.6 Cu ft tuned to 35 Hz for music or if its only for LFE then tunning at 25 Hz in a 4.7 Cu ft encolure. It would be crossed over below 44-50 Hz.
I suupose i cannot use the 10 inch quatro for extreme low frequency. any thing below 40 Hz would need too much displacement and would induce distortion. thats why 4 drivers come into play .
One thing on my mind is that why to bother too much , its Fs=38 Hz with sealed 1.5 cu Feet enclosure i may get around 44 Hz FB or pull push in sealed 1.8 would give Fb=48 Hz. Just wondering if thats too high ??? Any idea for shooting it as well ????
look at how -6db, and -12db transforms, and changes
like say, -6db at 45hz, and -12db at 30hz, could be very good
-6db at 45hz, and -12db at 40hz, less good
or, even -6db at 50hz could be good, if -12db is at 30hz
(just theoretical figures, and not exact ones)
and so on
round and smooth rolloff, without sudden changes, is usually a good sign
but not all drivers can do that
nah, that would be closed box design
in BR, I reckon -6b at 30hz would make sense
Originally Posted by weltersys
Push Pull models the same as any ported speaker.
Try turning one around in your present box to see if the back vent makes whistling noises, noises can be far more annoying than the even order harmonic distortion that PP reduces.
Some spyders are "open weave" and make noise also.
Push Pull models the same as any ported speaker.
Try turning one around in your present box to see if the back vent makes whistling noises, noises can be far more annoying than the even order harmonic distortion that PP reduces.
The back vent I mentioned is the speaker cooling vent, some speakers vents are so noisy at high power (Lab 12, for instance) that they are easily heard when the magnet side is out.
Some spyders are "open weave" and make noise also.
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The cone response is about F3=36 Hz, port response is centered at 26 Hz, combined response results in an F3 around 30 Hz, and a "hump" of around +6 dB around 60 Hz.
In many rooms the VLF will increase, which could flatten the LF curve out and may result in a pleasing (to most) LF boost to Fb or lower. LF response will vary greatly with room size, shape, and placement.
This is not a speaker most would feel inclined to add a subwoofer below, especially one that is tuned higher than the top box.
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so what u suggest ? i got driver for wilson watch dog. as mentioned they emailed that for Ht use i m use 4.6 Cu ft with 6 inch port tuned to 25 Hz. does it make any sense ?
I know for most critical listening and music the VLF room gain would give flat to 30 Hz and driven by krell 600 FPB its very pleasing indeed. However in Ht it lacks the punch and rumble . Hence this project .
BTW i am comparing it to a system with pradigm subwoofers 15 inch in custom enclosures below 44 Hz duty. and peavey low rider 15 inch woofer in 5 cufeet enclosure Fb at 34 Hz F3 38 Hz crossed over for Bass above 44 HZ tlll 100 Hz. I tell you the mix and match of rumble of paradigm and puch of 15 inch 95 db efficient pro woofers is incredible even just at around 50 watts.
I know for most critical listening and music the VLF room gain would give flat to 30 Hz and driven by krell 600 FPB its very pleasing indeed. However in Ht it lacks the punch and rumble . Hence this project .
BTW i am comparing it to a system with pradigm subwoofers 15 inch in custom enclosures below 44 Hz duty. and peavey low rider 15 inch woofer in 5 cufeet enclosure Fb at 34 Hz F3 38 Hz crossed over for Bass above 44 HZ tlll 100 Hz. I tell you the mix and match of rumble of paradigm and puch of 15 inch 95 db efficient pro woofers is incredible even just at around 50 watts.
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