mista2,
....... ohhhh.
john van ommen,
I understand cabin gain, and I'm not expecting these to get any where near as loud. My car is a Lexus sc300, quite small and that subwoofer can really move.
I've modeled Bandpass enclosures, thir responce plots look awful to me, they are not smooth at all. They have giant peaks. Also WinISD automatically calculated optimum enclosures, for a 6th order bandpass there was no optimum, they were all awful.
GM,
When are you going to come listen to the FE127s?
Thanks,
Josh
....... ohhhh.
john van ommen,
I understand cabin gain, and I'm not expecting these to get any where near as loud. My car is a Lexus sc300, quite small and that subwoofer can really move.
I've modeled Bandpass enclosures, thir responce plots look awful to me, they are not smooth at all. They have giant peaks. Also WinISD automatically calculated optimum enclosures, for a 6th order bandpass there was no optimum, they were all awful.
GM,
When are you going to come listen to the FE127s?
Thanks,
Josh
Greets!
I pinched my left side sciatic nerve shortly after leaving the voice message and with no medical insurance and too young for state care, it's a struggle just to perform the mimimum basics of anything that requires being upright, so I'm literally not 'up' to doing any more driving/walking than absolutely necessary.
Sorry, I should have called to cancel, but intense pain has a way of refocussing/narrowing your priorities to a pinpoint and I just flat forgot about it. Hopefully I'll have the opportunity at some later date.
GM
I pinched my left side sciatic nerve shortly after leaving the voice message and with no medical insurance and too young for state care, it's a struggle just to perform the mimimum basics of anything that requires being upright, so I'm literally not 'up' to doing any more driving/walking than absolutely necessary.
Sorry, I should have called to cancel, but intense pain has a way of refocussing/narrowing your priorities to a pinpoint and I just flat forgot about it. Hopefully I'll have the opportunity at some later date.
GM
stick with single reflex
Yes, I agree that dual reflex bandpass boxes can sound bad very easily. I don't believe that is due to their frequency response; I believe that's due to their poor group delay. Psychoacoustically we are more sensitive to timing problems than we are to frequency response glitches.
OTOH, it's quite easy to make a single reflex bandpass thats response is ruler flat.
John
Yes, I agree that dual reflex bandpass boxes can sound bad very easily. I don't believe that is due to their frequency response; I believe that's due to their poor group delay. Psychoacoustically we are more sensitive to timing problems than we are to frequency response glitches.
OTOH, it's quite easy to make a single reflex bandpass thats response is ruler flat.
John
john van ommen,
I have also modeled 4th order bandpass. Below is the optimum enclosure of 4th order bandpass, but still doesn't give me any more SPL than the bass reflex box and gives less low end.
GM,
Sorry to hear that, hope you feel better soon. I was thought it would be nice for you to hear them. When you feel well enough to venture out for listening please call me, I'd be more than happy to make time for you to listen.
I was also wondering, my port (slot port) is going to run paralel the the bottom of the enclosure and it will drop out of the bottom to become downfiring (make a 90degree turn). I was wondering If I make the bottom piece of the enclosure rounded slightly so that the inside of the port is rounded (not the outside) will that effect my tuning frequency?
Thanks,
Josh
edit: And the picture, by the way green is bass reflex
I have also modeled 4th order bandpass. Below is the optimum enclosure of 4th order bandpass, but still doesn't give me any more SPL than the bass reflex box and gives less low end.
GM,
Sorry to hear that, hope you feel better soon. I was thought it would be nice for you to hear them. When you feel well enough to venture out for listening please call me, I'd be more than happy to make time for you to listen.
I was also wondering, my port (slot port) is going to run paralel the the bottom of the enclosure and it will drop out of the bottom to become downfiring (make a 90degree turn). I was wondering If I make the bottom piece of the enclosure rounded slightly so that the inside of the port is rounded (not the outside) will that effect my tuning frequency?
Thanks,
Josh
edit: And the picture, by the way green is bass reflex
An externally hosted image should be here but it was not working when we last tested it.
You're tuning it too low.
That's true, the ported box you modeled there will have more low bass in a anechoic chamber. But you're putting this in a CAR aren't you? I've personally built dozens of bandpass boxes for cars, as well as sealed, ported, and even horns. I'm running a horn sub in my Accord right now.
See, in the car, everything changes. Because of cabin gain, that box is going to have a HUGE bump at 40hz.
That's the trick all the pros use to get big SPLs in a car. If you aim for response that falls off slowly, it complements the cabin gain, and you end up with HUGE spl.
Try modeling that bandpass with a sealed chamber that has a higher Qtc (smaller box), and is tuned higher. You might consider using a passive radiator, as your port could end up taking up more space than the box!
John
That's true, the ported box you modeled there will have more low bass in a anechoic chamber. But you're putting this in a CAR aren't you? I've personally built dozens of bandpass boxes for cars, as well as sealed, ported, and even horns. I'm running a horn sub in my Accord right now.
See, in the car, everything changes. Because of cabin gain, that box is going to have a HUGE bump at 40hz.
That's the trick all the pros use to get big SPLs in a car. If you aim for response that falls off slowly, it complements the cabin gain, and you end up with HUGE spl.
Try modeling that bandpass with a sealed chamber that has a higher Qtc (smaller box), and is tuned higher. You might consider using a passive radiator, as your port could end up taking up more space than the box!
John
mista2 said:
Oops, I guess there's a little proud father in me.
Q Components http://www.q-components.com/
Page 34 of the catalogue
That's the one.
edjosh23 said:
See above. Pioneer 8" flat with added PVA glue mass
I wonder how they'd do in a Cornu spiralhorn?
http://www.6moons.com/audioreviews/cornu/cornu.html
CAD drawings
I threw together some CAD drawings of my sub, with the top, front, and left side panels removed to see the internal framework. On the bottom of the front side, you'll see two openings - a wide one on the left, and a narrow on the right. In that left opening is where the driver is mounted, and the right opening is the actual port. (I hope that made sense....) 😉
Behind the driver up to the first bend is the stuffed section.
If anyone is interested and wants more info (dims, etc), let me know!
Reece
I threw together some CAD drawings of my sub, with the top, front, and left side panels removed to see the internal framework. On the bottom of the front side, you'll see two openings - a wide one on the left, and a narrow on the right. In that left opening is where the driver is mounted, and the right opening is the actual port. (I hope that made sense....) 😉
Behind the driver up to the first bend is the stuffed section.
If anyone is interested and wants more info (dims, etc), let me know!
Reece
Attachments
Yesterday I got a quite a bit of work done. I must say, this new box is rediculously loud! After setting up the subwoofer I put on a bass test song, ten seconds after starting the sub my mom comes running into my room "Turn that down! Things are going to fall off the wall, that is way too loud." They still have great sound quality just with a lot more output. Thanks for you all's help. By the way, anny suggestions for a table top for this? I can't decide what type of wood I want.
pictures below.
Thanks,
Josh
pictures below.
Thanks,
Josh
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
mista2 said:
Greets!
Yeah, JVO kinda/sorta 'opened mouth before engaging brain' and I assume his lack of responding to my Q is his tacit agreement. He is correct though that it's a poor candidate for a compression loaded horn, though I wonder if he knows the real reason Vs the usual 'Pavlov's response' of it doesn't have a high BL motor.
Anyway, wide BW BLHs are glorified BRs, so if it can be tuned low in a BR without rolling off too much it will work fine in a BLH. Indeed, down low, higher Qts drivers are desirable since we don't want/need gain much beyond 100 Hz.
Right, due to the BW, they're huge if not folded into a corner. An ideal one OTOH is so stupid huge that it takes the displacement of a basement or attic since its Fc is down in the single digits, so you design an ideal horn and then 'slice' a portion of it out that best meets the performance parameters of the app. This is how the early designers did it, but T/S and especially computer software got designers thinking they could improve on it, though I've yet to reverse engineer a current compromised design that does as well IMO. "Physics, it's the law." 😉
GM
Greets!
Thanks for the thought and hopefully I'll be able to call soon!
Not really, it takes a large radius to make an audible difference if it's already a low vent mach design.
GM
Explain Away, Genius.
Ok, GM, according to you, I've "opened my mouth before engaging my brain." Would you care to elaborate on that? Specifically, what makes you think that this TB woofer would work well in a BLH?
Have you modeled it in hornresp or Mathcad?
John
Ok, GM, according to you, I've "opened my mouth before engaging my brain." Would you care to elaborate on that? Specifically, what makes you think that this TB woofer would work well in a BLH?
Have you modeled it in hornresp or Mathcad?
John
Parts Express now has the 5" TB woofer, and all the other drivers that Nuera used to have plus a couple extras
Nice looking box, Josh! Glad it sounds good! Sorry I have no suggestions for a table top, but I think it looks very nice as it is.
Thanks,
Unfortunately I've had too much school and I'm going out of town on friday so I haven't been able to sand or search for wood yet. After listening to this for a while now, I must admit, this has more bass than my ed13kv.2. I've got a slight air leak around the driver frame, I'll have to fix that, but otherwise these are great.
I've yet to watch a movie on them too, which I've really been waiting for.
Thanks,
Josh
Unfortunately I've had too much school and I'm going out of town on friday so I haven't been able to sand or search for wood yet. After listening to this for a while now, I must admit, this has more bass than my ed13kv.2. I've got a slight air leak around the driver frame, I'll have to fix that, but otherwise these are great.
I've yet to watch a movie on them too, which I've really been waiting for.
Thanks,
Josh
Re: Explain Away, Genius.
Greets!
Sorry for the tardy response.
I already 'elaborated' in my previous responses. 😉
No, but I don't really need to since once you understand the basics, it's as easy to calc as a T/S max flat alignment using Leach's math. For example, since this would be for 'sub' duty we're only concerned with max gain, so here's a 40 Hz Fc BLH 2pi space expo design for you to sim and get back to us with your thoughts:
Vf = 18.767"^2
L = 133.353"
St = 4.078"^2
Sm = 571.57"^2
Of course we can go lower, all the way down to <11 Hz, but size rapidly escalates to the ridiculous:
L = 1052.16"
Sm = 66612.84"^2
With the 'tail wagging the dog' this hard, don't have a clue just how low/loud it would actually play, but it sure would be cool looking, seeing a dinky little driver pumping out room shaking vibes with no obvious cone movement from a large room wall size mouth, though probably not for any extended subsonic notes due to motor heating. 😉
GM
john van ommen said:
Greets!
Sorry for the tardy response.
I already 'elaborated' in my previous responses. 😉
No, but I don't really need to since once you understand the basics, it's as easy to calc as a T/S max flat alignment using Leach's math. For example, since this would be for 'sub' duty we're only concerned with max gain, so here's a 40 Hz Fc BLH 2pi space expo design for you to sim and get back to us with your thoughts:
Vf = 18.767"^2
L = 133.353"
St = 4.078"^2
Sm = 571.57"^2
Of course we can go lower, all the way down to <11 Hz, but size rapidly escalates to the ridiculous:
L = 1052.16"
Sm = 66612.84"^2
With the 'tail wagging the dog' this hard, don't have a clue just how low/loud it would actually play, but it sure would be cool looking, seeing a dinky little driver pumping out room shaking vibes with no obvious cone movement from a large room wall size mouth, though probably not for any extended subsonic notes due to motor heating. 😉
GM
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