This approximation from @Brian Steele uses ts parameters to size a generic qw pipe. (It also exposes a lot of the size issues that carcaudio SPL drivers present.
i hope you build the skinny TL and drive it hard. it would be nice to finally see someone do something besides the rediculous stuff in FB groups with the drivers ‘Sd’ x Fs/4 as the only method/math used to ‘design’ these ignorantly
i hope you build the skinny TL and drive it hard. it would be nice to finally see someone do something besides the rediculous stuff in FB groups with the drivers ‘Sd’ x Fs/4 as the only method/math used to ‘design’ these ignorantly
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The process is no different than pro audio. Play 20hz tone over 24 hours in free air. However, most (like myself) just install and let the driver break in thru regular music play over drive time.
I did notice the difference in output from when I 1st installed the JBL GX1200 in my current BP4 enclosure until I removed the enclosure a couple of weeks ago. I thought the driver sounded terrible compared to the Coustic HT-612. Once broken in, the JBL sounded just as good. However, the Coustic is more efficient due to the treated paper cone.
What are the throat and mouth velocities at 130cm2 with max voltage at xmax?
How do you properly design a resonator in horn response if you didn’t break the driver in and measure the real TS parameters first? Why even bother playing around in horn response when it’s all a work of fiction ?
I had a (skar ddx12) in a paraflex for over a year that got the snot beat out of it , but the incredible cone control left the thing stiff and high Fs almost as new When I put that crazy box in the fire pit.
(I wonder to what extent this scenario is in other tapped pipes/horns ??)
Booger, just find the wavelength and quarter it. That's the QW resonator. As long as that length is kept, changing Sd won't change frequency, only pipe artefacts in the form of resonance and this chuffing thing. Any driver that can create those fundamentals strongly in the pipe will also invoke the resonances and this cant be filtered electronically apart from the volume control!
What is the basis of your contention that a 32hz pipe can be anything other than a 32hz pipe? This would have to be true for a driver to change the pipe's inherent property. If the driver has a Fs below the QW frequency than the pipe places a 32Hz filter and if the driver has a Fs higher than it just won’t reach target tuning
Once again, everyone needs to keep in mind that we have a size constraint to how large the box can be and a tuning constraint of minimum 33Hz. What better test box than the max allowed?
Seriously, someone, please explain this most basic of things. Having the max allowed box size in hand with a port designed to minimise pipe artefacts and adjustable to tuning frequency first. Then tube rolling some drivers through that with a mic pointed and REW eager. How is this not a realistic auditioning process to find a driver that can fill that box. We have already seen the results of buying from datasheets and the inconsistencies in the datasheets of known brands too
I need a better system than grabbing pics from my iCloud. Will set up a video pickup for what's going on here. A difficulty is the very old state of this place we got and some pics and vids will have to wait until my work area is a bit more presentable with a very tight budget
Remembered to pick up 300g of play dough today for Vas measurement. Moving the Yamaha console to this area too. New triangular studio desk and work table under build right now
Because all of my current qw resonators, except the higher order versions, uses taper to shorten the line length and take advantage of the wider bandwidth and cleaner XO region right above it.
generic qw resonators as you described are leaving a lot of unneeded /unwanted potential size and Shape issues(resonances) , not much different than using a strangely inappropriately sized box or strange musical instrument nobody wants to listen to
generic qw resonators as you described are leaving a lot of unneeded /unwanted potential size and Shape issues(resonances) , not much different than using a strangely inappropriately sized box or strange musical instrument nobody wants to listen to
But this taper, why does it have to be even taper from one end to the other? Have you tried this in sims? Say 3 segments, taper on the first, flat second and reverse taper on the last. Watch what happens to exit velocity and pipe artefacts
And we are diverging into TL again. Let's get back to the bass reflex and build the largest that I can fit in storage. We can always make the volume smaller with foam blocks and I keep saying that the port fitting is removable
And we are diverging into TL again. Let's get back to the bass reflex and build the largest that I can fit in storage. We can always make the volume smaller with foam blocks and I keep saying that the port fitting is removable
This current thread is the design and build of the single cab solution mentioned in the link below
https://www.diyaudio.com/community/threads/point-source-efficient-tops-dubwoofer.414311/
Pretty much the SOR or statement of requirements in plain detail, including the options from personal research into likely shopping cart. Two weeks, hoping for some suggestions for a likely driver that may fill the role, with none forthcoming from the 'experts'. There are many drivers out there that don't always come up in searches
Going in with a gamble and getting that shopping list delivered
Making the effort in working out the best possible auditioning boxes
I think I am doing well in finding a viable solution through solo effort, and also making the effort to try to learn about acoustic engineering implications arising as the project makes progress. Very thankful for the constructive commentary from the likes of GM, Art, BPFanatic1
So are we all speaking up now to deconstruct?
https://www.diyaudio.com/community/threads/point-source-efficient-tops-dubwoofer.414311/
Pretty much the SOR or statement of requirements in plain detail, including the options from personal research into likely shopping cart. Two weeks, hoping for some suggestions for a likely driver that may fill the role, with none forthcoming from the 'experts'. There are many drivers out there that don't always come up in searches
Going in with a gamble and getting that shopping list delivered
Making the effort in working out the best possible auditioning boxes
I think I am doing well in finding a viable solution through solo effort, and also making the effort to try to learn about acoustic engineering implications arising as the project makes progress. Very thankful for the constructive commentary from the likes of GM, Art, BPFanatic1
So are we all speaking up now to deconstruct?
Lazy. You gotta start somewhere.
Since I had no specs to work with regarding the Coustic Power Logic HT-612 (freebie), I measured the driver, modeled in HR, and then built the enclosure.
With the JBL GX1200's, it's bascally the same as the CX1200, CS1214, etc. They been measured plenty of times on the net.
I never measured my Kicker 08S15L74 and it's been a BP4 in a truck for a few years and then put in a T-TQWT in 2012 for home theater. Still playing strong after all these years. My son beats on it whenever he comes home.
Sd is the driver's effective cone area.
A large port volume is required for drivers with large displacement to keep the wiggling slug of air that makes low frequency sounds within the port area.
A large cross section, tapered port inlet and exit helps the slug of air to function like a piston, rather than an air cannon
A large port volume is required for drivers with large displacement to keep the wiggling slug of air that makes low frequency sounds within the port area.
A large cross section, tapered port inlet and exit helps the slug of air to function like a piston, rather than an air cannon
With a port such as the one depicted in your OP, use it's cross sectional area prior to the flares.
The reason ports have become larger is driver displacement has increased.
More driver displacement requires larger port area, larger port area requires longer ports, smaller cabinets require longer ports than larger cabinets for the same Fb...
A port's output won't increase linearly with input level once it starts to "blow" and "suck", rather than act as an oscillating slug of air resonating around the Helmholtz frequency.
In other words, if you want to use the driver's increased displacement effectively, the port must be big.
Anyway, your questions sound like a product of sleep deprivation with coffee overdose, we covered all this before in discussions about passive radiators.
Have fun at the theatre thing...
I am trying to focus on this slugs face. Does it have one and does that surface area act as a passive driver? If it does than my pipe cross section is only 60cm2. As a slot, this translates more like a blade than a slug
Trying to understand the relationship between port cross section and SPL
Ï picture a ball that is a fraction wider on the end of a pipe. How it would oscillate
Maybe a narrower pipe can toss a larger ball in a larger cup? There is something here that feels like I am on the verge of getting
Good day today. Jiya is representing her school with both the double bass in strings and electric bass in concert band
Duets on Friday but missed out one performance as the parent who took on to register the trio found the online application challenging