Why would you want to change to a higher crossover frequency?
Or are you just saying use the damping for a low-pass filter?
(that since the damping is an acoustic low-pass filter, maybe less of an electrical filter would be needed).
If so, yes, we're on the same page, that was the original thought/reason for using felt.
Or are you just saying use the damping for a low-pass filter?
(that since the damping is an acoustic low-pass filter, maybe less of an electrical filter would be needed).
If so, yes, we're on the same page, that was the original thought/reason for using felt.
Well my first test results;
The purpose is to loosen up the drivers.
Playing various "ultimate bass" videos off of YouTube through my Carver Reciever.
My 16 year old son's comment, while standing right in front of the sub, "that isn't a sub, it's an air conditioner."
My lovely bride working on her computer about 5 feet a way said she was getting nauceous, and asked me if the sub could do that?
I will do proper testing soon. My rat shack meter says I was getting up to 105 db at about 1 meter in my computer area. I have no idea what the power rating of my Carver receiver is.
Paul
The purpose is to loosen up the drivers.
Playing various "ultimate bass" videos off of YouTube through my Carver Reciever.
My 16 year old son's comment, while standing right in front of the sub, "that isn't a sub, it's an air conditioner."
My lovely bride working on her computer about 5 feet a way said she was getting nauceous, and asked me if the sub could do that?
I will do proper testing soon. My rat shack meter says I was getting up to 105 db at about 1 meter in my computer area. I have no idea what the power rating of my Carver receiver is.
Paul
I would say the 12dB filter is the culprit. With such a low order, a lower cutoff frequency is required than with a 24db or even higher order filter.
Small example: With 12db filter at 70hz cutoff, it follows, that at 140hz the signal is lowered by 12db. Since most horns have a rising response, it could well be, that the signal at 140hz is at the same level as at 70hz. 280hz is -24db or rather the "real" -12db point, since the woofer should loose its rising response by now. Now add to that that the hearing gets more sensitive at higher frequencies and you could imagine that you hear your "sub" well into the midrange.
Small example: With 12db filter at 70hz cutoff, it follows, that at 140hz the signal is lowered by 12db. Since most horns have a rising response, it could well be, that the signal at 140hz is at the same level as at 70hz. 280hz is -24db or rather the "real" -12db point, since the woofer should loose its rising response by now. Now add to that that the hearing gets more sensitive at higher frequencies and you could imagine that you hear your "sub" well into the midrange.
aceinc said:
Got to love a TL's/horn's directivity.
Set a female's suspended reproductive system into oscillation and it can get messy. This is why I limited the horn system I had to a foreshortened ~80 Hz and let corner loading boost its sealed bottom end to blend to EBS/MLTL subs. Even then, they would still occasionally leave the house if I cranked it up to ~ 'live' on DSOTM or similar.
GM
TH-SPUD with a pair of Trio8's. I guess I could start a thread about the build. I haven't posted too much here as the thread is so big no one would find it after a day or two anyway. I did start a build thread over at HomeTheaterShack.com.
I will at a minimum do some testing in my living room. I may do tests in my front yard which is about 1 acre open area. The testing will wait until next weekend, in the mean time I will try to break in the drivers.
The initial playing was in my computer area. I have an old Carver receiver attached to my computer.
Paul
I will at a minimum do some testing in my living room. I may do tests in my front yard which is about 1 acre open area. The testing will wait until next weekend, in the mean time I will try to break in the drivers.
The initial playing was in my computer area. I have an old Carver receiver attached to my computer.
Paul
serenechaos said:
Yes, my tapped horn sounds like that when I drive it without the crossover. The "echo" you are hearing is just that - it's the big peak in the midbass that occurs due to constructive interference.
To make it go away, adjust your crossover.
Also, my listening room uses eight subs, which prevents one sub from "dominating" over the others. This helps a great deal.
I posted this earlier;
I am a bit fuzzy on the Ang parameter in HornResp. I have been using 2.0 x Pi for my calculations, how does this number relate to the real world?
And couldn't find an answer. I believe this parameter was discussed earlier in the thread, but I couldn't find the discussion either.
Is 2.0 x Pi equivalent to an open field?
Paul
I am a bit fuzzy on the Ang parameter in HornResp. I have been using 2.0 x Pi for my calculations, how does this number relate to the real world?
And couldn't find an answer. I believe this parameter was discussed earlier in the thread, but I couldn't find the discussion either.
Is 2.0 x Pi equivalent to an open field?
Paul
aceinc said:
Hi Paul,
For the purpose of the exercise, and without wishing to get too technical, assume that you have a loudspeaker in a very large square or rectangular room:
4.0 x Pi = speaker suspended halfway between the ceiling and the floor, in the middle of the room, well away from the four walls.
2.0 x Pi = speaker sitting on the floor in the middle of the room, well away from the four walls.
1.0 x Pi = speaker sitting on the floor against one of the walls, halfway along the wall from the corners.
0.5 x Pi = speaker sitting on the floor in a corner.
Kind regards,
David
2Pi=Standing on the ground: That´s close enough as a thinking model for most cases.
Of course, the walls (the ground) have to be 100% reverberative. A speaker standing on a clammy grassland will loose some of the boundary effects compared to one standing on solid concrete.. Keep in mind when thinking about max SPL figures in Pro-Sound.
Actually, the front baffle of the enclosure also acts as a reflecting surface. When dealing with subwoofers, wavelength most of the time ist too big and enclosure size ist too small for this to be relevant, but when thinking in pro-sound categories, a 60x100cm² front baffle sure is big enough to bundle frequencies in the midbass section, so you actually have a transition between 2Pi-Space and 1Pi-Space to the upper frequencies of the sub.
Akabak can take these circumstances into account, LSPCad also has some features for this (but is no good when dealing with horns..) and AjHorn does some assumptions (one can choose between 2Pi and "floor"..).
Of course, the walls (the ground) have to be 100% reverberative. A speaker standing on a clammy grassland will loose some of the boundary effects compared to one standing on solid concrete.. Keep in mind when thinking about max SPL figures in Pro-Sound.
Actually, the front baffle of the enclosure also acts as a reflecting surface. When dealing with subwoofers, wavelength most of the time ist too big and enclosure size ist too small for this to be relevant, but when thinking in pro-sound categories, a 60x100cm² front baffle sure is big enough to bundle frequencies in the midbass section, so you actually have a transition between 2Pi-Space and 1Pi-Space to the upper frequencies of the sub.
Akabak can take these circumstances into account, LSPCad also has some features for this (but is no good when dealing with horns..) and AjHorn does some assumptions (one can choose between 2Pi and "floor"..).
AndrewT said:
Hi Andrew,
Unfortunately you have now required me to get a bit technical
.4 / 3 * Pi * r ^ 3 must be a volume if r is cubed.
If r = radius then
Sphere volume = 4 / 3 * Pi * r ^ 3
Sphere surface area = 4 * Pi * r ^ 2
The Hornresp Ang radiation parameter actually refers to a solid angle (measured in steradians) rather than to a surface area. Google on the word "steradian" if you would like to know more.
Kind regards,
David
you're right.David McBean said:
Hi Andrew,
Unfortunately you have now required me to get a bit technical
4 / 3 * Pi * r ^ 3 must be a volume if r is cubed.
If r = radius then
Sphere volume = 4 / 3 * Pi * r ^ 3
Sphere surface area = 4 * Pi * r ^ 2
The Hornresp Ang radiation parameter actually refers to a solid angle (measured in steradians) rather than to a surface area. Google on the word "steradian" if you would like to know more.
Kind regards,
David
I must stop using my brain, it's beginning to resemble a CDrom that gone wrong.