infinate baffle...
Pro
Joined: May 2007
Posts: 744
Likes: 0
From: WayTooCloseToNY Northeast PA
The Dayton is the better driver of the two, and after seeing the specs, AcousticVisions is misrepresenting his sensitivity values. That combined with the questionable xmax number causes me not to trust him.
Le Mans Master
Joined: Sep 2004
Posts: 5,707
Likes: 4
From: Los Angeles
Wow. I was gone all day and just got back. What a mess here. 
I see no advantage to that membrane crap at all. Yes it is indeed different than a passive radiator. Spkrboy has the rest covered. 
Except Scott_fx's question about extended response. A ported enclosure will extend the low frequency response of a woofer approximately 1/2 octave. Typically, if you desire an IB, you choose a woofer that will have a lower Fs which is more desirable for that application to make up for some of that. Most automotive subs have a very high Fs and a ported enclosure is almost a must if you want any real bass. The advantage is lower phase distortion because you are not mixing the output of a port with the sub. Some times you feel like a nut, some times you don't. 
I see no advantage to that membrane crap at all. Yes it is indeed different than a passive radiator. Spkrboy has the rest covered. Except Scott_fx's question about extended response. A ported enclosure will extend the low frequency response of a woofer approximately 1/2 octave. Typically, if you desire an IB, you choose a woofer that will have a lower Fs which is more desirable for that application to make up for some of that. Most automotive subs have a very high Fs and a ported enclosure is almost a must if you want any real bass. The advantage is lower phase distortion because you are not mixing the output of a port with the sub. Some times you feel like a nut, some times you don't.
Thread Starter
Le Mans Master
Joined: Jun 2004
Posts: 5,572
Likes: 4
From: Los Angeles Ca
So I'm ready to purchase the equipment for my (home) IB setup.
it's going to consist of
two 15" Dayton IB subs:
http://www.partsexpress.com/pe/pshow...95-455&scqty=4
Behringer DSP1124P Feedback Destroyer Pro w/Parametric EQ:
http://www.partsexpress.com/pe/pshow...TOKEN=20305222
but i'm not sure how much power to throw at these things now. my room is small, I'd say 16 x 16 x 8 but there is a big archway that goes into the dining room. I've should i feed them 350 wrms each or can i get away with less?
btw if my post isn't complete, forgive me. it's 2:30 am and i'm still at work and i havent had a day off for two weeks
would pone of these work?:
http://www.partsexpress.com/pe/showd...604728#reviews
http://www.partsexpress.com/pe/pshow...TOKEN=20305222
i know behringer isn't the cleanest thing out there but we're talking distortion below 100hz which is harder to hear
it's going to consist of
two 15" Dayton IB subs:
http://www.partsexpress.com/pe/pshow...95-455&scqty=4
Behringer DSP1124P Feedback Destroyer Pro w/Parametric EQ:
http://www.partsexpress.com/pe/pshow...TOKEN=20305222
but i'm not sure how much power to throw at these things now. my room is small, I'd say 16 x 16 x 8 but there is a big archway that goes into the dining room. I've should i feed them 350 wrms each or can i get away with less?
btw if my post isn't complete, forgive me. it's 2:30 am and i'm still at work and i havent had a day off for two weeks
would pone of these work?:
http://www.partsexpress.com/pe/showd...604728#reviews
http://www.partsexpress.com/pe/pshow...TOKEN=20305222
i know behringer isn't the cleanest thing out there but we're talking distortion below 100hz which is harder to hear
Last edited by scott_fx; Aug 14, 2007 at 05:42 AM.
Le Mans Master
Joined: Sep 2004
Posts: 5,707
Likes: 4
From: Los Angeles
but i'm not sure how much power to throw at these things now. my room is small, I'd say 16 x 16 x 8 but there is a big archway that goes into the dining room. I've should i feed them 350 wrms each or can i get away with less?
btw if my post isn't complete, forgive me. it's 2:30 am and i'm still at work and i havent had a day off for two weeks
would pone of these work?:
http://www.partsexpress.com/pe/showd...604728#reviews
http://www.partsexpress.com/pe/pshow...TOKEN=20305222
i know behringer isn't the cleanest thing out there but we're talking distortion below 100hz which is harder to hear
btw if my post isn't complete, forgive me. it's 2:30 am and i'm still at work and i havent had a day off for two weeks
would pone of these work?:
http://www.partsexpress.com/pe/showd...604728#reviews
http://www.partsexpress.com/pe/pshow...TOKEN=20305222
i know behringer isn't the cleanest thing out there but we're talking distortion below 100hz which is harder to hear
350/ch should be plenty.
Pro
Joined: May 2007
Posts: 744
Likes: 0
From: WayTooCloseToNY Northeast PA
There's no such thing as too much amplifier power. There is such a thing as not enough. I'm curious about the feedback suppressor myself.
If you insist on active EQ, this might be a better starting point if you're electronically inclined: http://www.trueaudio.com/st_lkxfm.htm
If your room is actually square, you'll have a hell of a room mode to drag down, so a notch filter might be all you'll need. One way to control these modes is to mount the drivers in adjacent corners of the room. Corner-loading usually results in the highest output from the driver, but at the expense of excitation of every room mode. Mounting similar drivers in adjacent corners results in a cancellation of much of this excitation while maintaining the output that corner-loading provides.
If you insist on active EQ, this might be a better starting point if you're electronically inclined: http://www.trueaudio.com/st_lkxfm.htm
If your room is actually square, you'll have a hell of a room mode to drag down, so a notch filter might be all you'll need. One way to control these modes is to mount the drivers in adjacent corners of the room. Corner-loading usually results in the highest output from the driver, but at the expense of excitation of every room mode. Mounting similar drivers in adjacent corners results in a cancellation of much of this excitation while maintaining the output that corner-loading provides.
Melting Slicks
Joined: Aug 2006
Posts: 2,866
Likes: 45
From: Tampa Bay, Go BUCS!!!Go Rays!!!Go Lightning!!!
St. Jude Donor '12-'13-'14
You guys are so far over my head I'm a little afraid to come in here, but hey, wisdom isn't my strong suit 
.
What I've gathered here so far is that the IB setup is a way to "cheat" and use the entire trunk as a sub box without losing the ability to use it as a trunk.
Knowing that the trunk is too large for most drivers (even 2-15"s) you sacrific a little space by making a very small enclosure and making the back of it a flexible membrane. You're actually losing this space anyway since the drivers take up almost the same amount of space themselves. The fact that the membrane exists helps reduce the ill effects of having a "too-large" sub box and the fact that it is flexible helps reduce the effect of having a "too-small" sub box.
How close it that in layman terms?
And if it is "close enough", I can't see any advantage to doing this in a house where I'd think you'd always have room for a proper size box (even if it is in the ceiling).
Thanks for humoring me.
.What I've gathered here so far is that the IB setup is a way to "cheat" and use the entire trunk as a sub box without losing the ability to use it as a trunk.
Knowing that the trunk is too large for most drivers (even 2-15"s) you sacrific a little space by making a very small enclosure and making the back of it a flexible membrane. You're actually losing this space anyway since the drivers take up almost the same amount of space themselves. The fact that the membrane exists helps reduce the ill effects of having a "too-large" sub box and the fact that it is flexible helps reduce the effect of having a "too-small" sub box.
How close it that in layman terms?
And if it is "close enough", I can't see any advantage to doing this in a house where I'd think you'd always have room for a proper size box (even if it is in the ceiling).
Thanks for humoring me.
Melting Slicks
Joined: Dec 2004
Posts: 2,394
Likes: 0
From: Bay Area CA
A ported enclosure will extend the low frequency response of a woofer approximately 1/2 octave.
Fej
Le Mans Master
Joined: Sep 2004
Posts: 5,707
Likes: 4
From: Los Angeles
This only applies above the tuning frequency of the enclosure correct? IE if a sub in the proper sealed enclosure has an fs of say 40hz, the same sub would have an fs of 32hz when ported correct? (all numbers are approximate and used for example) You do not gain 1/2 octave below the tuning frequency of the port, you only gain 1/2 octave BY porting the enclosure (with a much sharper downturn in response below the tuning frequency)
Fej
Fej
In layman's terms: The point is to make the box and port resonate at a frequency below fs, thus adding extra oomph to that range thereby extending the output to 32hz in your example. Normally the response of a speaker falls off sharply below fs. The trick is to also make the box large/small enough to add enough output to keep up with the speaker. With a port, you can tune a small box to have a low resonance but the output might be insignificant. A box too large, tuned to the same frequency might over power and make the system sound muddy. The speaker specifications such as fs and Qts all tell you how big that box should be to match outputs.For infinite baffles, (not that membrane stuff) you would use a speaker specifically designed for that purpose, with a very low fs. No phase distortion from two output sources. They usually sound very good with some trade-offs and there are some companies that even make high end sound reinforcement models. Such as Bag End in Chicago.
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Thread Starter
Le Mans Master
Joined: Jun 2004
Posts: 5,572
Likes: 4
From: Los Angeles Ca
I'd look around for a cheap dedicated eq instead of that feedback suppressor. Why do you need an eq for a sub anyway? The sub barely covers more than one octave. You'll be better off with an Aphex 104 C2 exciter. I know where you can still get them.
350/ch should be plenty.
350/ch should be plenty.
There's no such thing as too much amplifier power. There is such a thing as not enough. I'm curious about the feedback suppressor myself.
If you insist on active EQ, this might be a better starting point if you're electronically inclined: http://www.trueaudio.com/st_lkxfm.htm
If your room is actually square, you'll have a hell of a room mode to drag down, so a notch filter might be all you'll need. One way to control these modes is to mount the drivers in adjacent corners of the room. Corner-loading usually results in the highest output from the driver, but at the expense of excitation of every room mode. Mounting similar drivers in adjacent corners results in a cancellation of much of this excitation while maintaining the output that corner-loading provides.
If you insist on active EQ, this might be a better starting point if you're electronically inclined: http://www.trueaudio.com/st_lkxfm.htm
If your room is actually square, you'll have a hell of a room mode to drag down, so a notch filter might be all you'll need. One way to control these modes is to mount the drivers in adjacent corners of the room. Corner-loading usually results in the highest output from the driver, but at the expense of excitation of every room mode. Mounting similar drivers in adjacent corners results in a cancellation of much of this excitation while maintaining the output that corner-loading provides.
I included the feedback supressor because i thought it was needed. If i recall when looking at the forums a lot of members were using them. I guess i'll try it w/o any eq'ing first then add the components that i need. I don't think my room is actually square, i think it's actually a rectangle. those figures were just a guess.
Le Mans Master
Joined: Sep 2004
Posts: 5,707
Likes: 4
From: Los Angeles
I included the feedback supressor because i thought it was needed. If i recall when looking at the forums a lot of members were using them. I guess i'll try it w/o any eq'ing first then add the components that i need. I don't think my room is actually square, i think it's actually a rectangle. those figures were just a guess.
What were they using feedback suppressors for?
That seems really odd to me unless there's some really clever new use for them. 
Pro
Joined: May 2007
Posts: 744
Likes: 0
From: WayTooCloseToNY Northeast PA
You can't just port any driver in any box. Drivers with a Qts higher than about 0.38 don't work all that well in ported boxes. Lower Qts drivers respond much more favorably, but you can still run into group delay problems if you haven't chosen the Fb correctly. If you look at the impedance curve of a ported-box driver, you'll see two spikes in the curve. The higher is the driver resonance, the lower one is due to the port. You can manipulate the port to really drop the lower spike, but there's an optimal position below which you cause tremendous low-frequency distortion and unloading of the driver.
jbondfl... correct, there's absolutely no way to use an aperiodic setup in a house. It's completely pointless. The trunk analogy is a bit oversimplified, but essentially right.
jbondfl... correct, there's absolutely no way to use an aperiodic setup in a house. It's completely pointless. The trunk analogy is a bit oversimplified, but essentially right.
5th Gear
Joined: May 2007
Posts: 5
Likes: 0
From: Helsingborg
What were they using feedback suppressors for? That seems really odd to me unless there's some really clever new use for them.
It´s great versatility for a great price if you want to flaten out your freq. response for you subwoofers. 12band/channel , 1/60 to 2 octave bandwith on each filter allows for some quite precise filtering....
So I would say price/performance is very good for DIY applications
Le Mans Master
Joined: Sep 2004
Posts: 5,707
Likes: 4
From: Los Angeles
but... but.... it's a Behringer. 
In all seriousness, if he uses it for sub output only, it will still be very difficult to get any benefit from it without an FFT or TEF analyzer. That's a very narrow range and trying to use more than one of those eq bands set to have such high Q will be very ominous at best. It just seems like a waste of money to me. I certainly wouldn't use it on the full range. The link to the product said it was a professional 24 bit 46k sample rate.
I hope that was a typo. The money would be better spent on a device designed to process sub output, such as the Aphex or a dbx.
In all seriousness, if he uses it for sub output only, it will still be very difficult to get any benefit from it without an FFT or TEF analyzer. That's a very narrow range and trying to use more than one of those eq bands set to have such high Q will be very ominous at best. It just seems like a waste of money to me. I certainly wouldn't use it on the full range. The link to the product said it was a professional 24 bit 46k sample rate.
I hope that was a typo. The money would be better spent on a device designed to process sub output, such as the Aphex or a dbx.
Thread Starter
Le Mans Master
Joined: Jun 2004
Posts: 5,572
Likes: 4
From: Los Angeles Ca
ok... so i'm holding off on the behringer.
quick question about the sub. I found these subs as well (18"):
http://www.soundsolutionsaudio.com/s...d&productId=51
(15")
http://www.soundsolutionsaudio.com/s...d&productId=50
how does it compare to the dayton (15"):
http://www.partsexpress.com/pe/pshow...95-455&scqty=4
quick question about the sub. I found these subs as well (18"):
http://www.soundsolutionsaudio.com/s...d&productId=51
(15")
http://www.soundsolutionsaudio.com/s...d&productId=50
how does it compare to the dayton (15"):
http://www.partsexpress.com/pe/pshow...95-455&scqty=4
Le Mans Master
Joined: Sep 2004
Posts: 5,707
Likes: 4
From: Los Angeles
ok... so i'm holding off on the behringer.
quick question about the sub. I found these subs as well (18"):
http://www.soundsolutionsaudio.com/s...d&productId=51
(15")
http://www.soundsolutionsaudio.com/s...d&productId=50
how does it compare to the dayton (15"):
http://www.partsexpress.com/pe/pshow...95-455&scqty=4
quick question about the sub. I found these subs as well (18"):
http://www.soundsolutionsaudio.com/s...d&productId=51
(15")
http://www.soundsolutionsaudio.com/s...d&productId=50
how does it compare to the dayton (15"):
http://www.partsexpress.com/pe/pshow...95-455&scqty=4
Pro
Joined: May 2007
Posts: 744
Likes: 0
From: WayTooCloseToNY Northeast PA
The key to an IB driver is a high Qts... >0.57. The Dayton qualifies, the SoundSolutions knockoffs aren't close.
Robvuk's right about the EQ. The filters need to be a lower Q to get at room modes correctly. I don't know a whole lot about pro equipment, but fundamentally, it's definitely an inappropriate application.
Robvuk's right about the EQ. The filters need to be a lower Q to get at room modes correctly. I don't know a whole lot about pro equipment, but fundamentally, it's definitely an inappropriate application.
Thread Starter
Le Mans Master
Joined: Jun 2004
Posts: 5,572
Likes: 4
From: Los Angeles Ca
great guys, i really appreciate the help.
now i have to figure out if it's going in the floor, under the fireplace or in the ceiling (last choice)
since i have your help. if i were to do a floor mounted IB setup. what is the smallest hole that i could cut into the floor. can i make the manifold wide (15"-16") but narrow... say 4" wide? I'd like to cover the hole with a cast iron register like this:
http://www.thehardwarehut.com/catalo...hp?p_ref=18911
is that a bad idea?
my other option involves the fireplace. originally i had planned on raising the bottom portion of my fireplace so that it sits flush with the bottom of the opening. here is a picture of a fireplace *like* mine
now visualize moving the bottom horizontal tiles up so they are even with the bottom of the door. I was going to leave the front open (covered with grill cloth) and put the a/v equipment in there. However; i could find another place for the a/v equipment and mount the subs in the floor under the platform?
now i have to figure out if it's going in the floor, under the fireplace or in the ceiling (last choice)
since i have your help. if i were to do a floor mounted IB setup. what is the smallest hole that i could cut into the floor. can i make the manifold wide (15"-16") but narrow... say 4" wide? I'd like to cover the hole with a cast iron register like this:
http://www.thehardwarehut.com/catalo...hp?p_ref=18911
is that a bad idea?
my other option involves the fireplace. originally i had planned on raising the bottom portion of my fireplace so that it sits flush with the bottom of the opening. here is a picture of a fireplace *like* mine
now visualize moving the bottom horizontal tiles up so they are even with the bottom of the door. I was going to leave the front open (covered with grill cloth) and put the a/v equipment in there. However; i could find another place for the a/v equipment and mount the subs in the floor under the platform?
Last edited by scott_fx; Aug 14, 2007 at 11:25 PM.
Le Mans Master
Joined: Sep 2004
Posts: 5,707
Likes: 4
From: Los Angeles
my other option involves the fireplace. originally i had planned on raising the bottom portion of my fireplace so that it sits flush with the bottom of the opening. here is a picture of a fireplace *like* mine
now visualize moving the bottom horizontal tiles up so they are even with the bottom of the door. I was going to leave the front open (covered with grill cloth) and put the a/v equipment in there. However; i could find another place for the a/v equipment and mount the subs in the floor under the platform?