Hello,
Like the title says, I am wondering what does term ripple mean when designing speaker/subwoofer enclosure. What it does, is it good or bad? Some definitions and tips would be appreciated.
Like the title says, I am wondering what does term ripple mean when designing speaker/subwoofer enclosure. What it does, is it good or bad? Some definitions and tips would be appreciated.
Enclosed boxes have the same eigenmodes [standing waves] as a room.
'Ripple' describes a +/- wave traveling through a medium, so a cab's panel can have ripple if it's weak enough to be flexed, absorbing some of the driver's output. This type construction is common for mechanically damping an under-damped speaker alignment or changing its 'tone' such as the BBC LS3/5A studio monitor.
GM
'Ripple' describes a +/- wave traveling through a medium, so a cab's panel can have ripple if it's weak enough to be flexed, absorbing some of the driver's output. This type construction is common for mechanically damping an under-damped speaker alignment or changing its 'tone' such as the BBC LS3/5A studio monitor.
GM
I suspect the poster is referring to ripples in the frequency response curve in the pass-band of the speaker.
Probably, but I like to just answer Qs and let them tell us if it's not what was meant as I really suck at mind reading. 😉
GM
GM
+1
Maybe it is a speaker enclosure with walnuts and bits of candy rattling inside like Chocolate Ripple ice-cream.
For sure, internal modes exist in boxes shy in the damping department (natural or added). And easy to ignore that acoustically transparent large hole known as the driver. Hard to imagine any practical amount of wall flexure in a properly built and braced, wood enclosure.
Or maybe it is one of those things like litz-wire audio cables that people with sensitive hearing (and a distaste for blind testing) can hear.
Ben
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Based on that assumption, ripple usually means you have a Q that is too high, a box that is too large or a tuning too high.
Ripple is a term commonly used when talking about 1/4 wave designs.
A 1/4 wave design has a train of harmonics coming out the terminus. In a perfect world we could keep the fundemental completely & kill the other harmonics completely. In the real world this is not acheivable, and we inevitably make a trade-iff between unwanted suppression of the fundemental, and non-suppression of the harmonics.
The unwanted harmonics cause ripple as they wave-train moves in & out of phase with the main radiation from the front of the cone.
dave
A 1/4 wave design has a train of harmonics coming out the terminus. In a perfect world we could keep the fundemental completely & kill the other harmonics completely. In the real world this is not acheivable, and we inevitably make a trade-iff between unwanted suppression of the fundemental, and non-suppression of the harmonics.
The unwanted harmonics cause ripple as they wave-train moves in & out of phase with the main radiation from the front of the cone.
dave
Sorry, I thought question was clear enough, didn't know there were multiple answers.
This is alpine type r subwoofer guide that has recommended enclosures. You can see it has "F3, ripple, Fb" box. (I am interested in third row, that's my sub)
Does it refer to peak in its response? Like: 33 or 36 Hz will be 2 dB louder than everything else.
This is alpine type r subwoofer guide that has recommended enclosures. You can see it has "F3, ripple, Fb" box. (I am interested in third row, that's my sub)
Does it refer to peak in its response? Like: 33 or 36 Hz will be 2 dB louder than everything else.
I believe in this case it is as you identified, a peak in the response around the tuning frequency. A response like this usually occurs when the driver is in an enclosure tuned 'too high', but being a car application I expect there are real limits placed on how long the port can physically be and hence how low the tuning can be brought.
In reality, the sealed alignment will usually be better in a car and the Qtc of around 0.7 indicates that the frequency response would be flat with no peaking. You'd get an earlier, but gentler, roll-off at the low end, usually very well complimented by your cabin gain 🙂
In reality, the sealed alignment will usually be better in a car and the Qtc of around 0.7 indicates that the frequency response would be flat with no peaking. You'd get an earlier, but gentler, roll-off at the low end, usually very well complimented by your cabin gain 🙂
Hi,
In this case its sipple ripple of "boombox" alignments
and at about 3dB its far too much and very clueless.
You would be far better off reducing the tuning frequency
of all the vented boxes to something a lot more sensible,
ignoring F3 and optimising F6 to F10, and low bass power,
distortion and extension. Probably bigger boxes too.
rgds, sreten.
The response will peak low down at the nominal passband level.
Above that it will dip about 3dB before returning to passband level.
Its very much IMO one note bass, and a very poor room alignment.
In this case its sipple ripple of "boombox" alignments
and at about 3dB its far too much and very clueless.
You would be far better off reducing the tuning frequency
of all the vented boxes to something a lot more sensible,
ignoring F3 and optimising F6 to F10, and low bass power,
distortion and extension. Probably bigger boxes too.
rgds, sreten.
The response will peak low down at the nominal passband level.
Above that it will dip about 3dB before returning to passband level.
Its very much IMO one note bass, and a very poor room alignment.
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Pretty much in this case.
Here is the family specs:
http://support.alpine-usa.com/products/documents/OM_SWR-1242D.PDF
A typical "maximally Flat" design for this woofer (If it is the 1222D) would be about 50 liters tuned to 26-27 Hz. If you tune higher than that, it will have a peak. Model it in WinISD or some other program using the parameters in the file and you can see the response shape that results.
For a Car, I'd put this woofer in a 1-1.5 cubic foot (30-40liter) sealed box and forget about it.
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Yes, it does, though the term ripple is rather misleading.
This is what it looks like in a ported box of 1.3 cuft with the box tuned to 36Hz.
The peak (+3dB) centers at 50Hz with F3 at 33Hz.
Regards
Mike
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The vented alignments give them a bit more output around 40 Hz. The extra 2dB of output around that frequency can make rap and other bass-heavy music sound a bit more impressive.
The Type Rs work fine in sealed boxes however, particularly if you give them enough power. I use two of the 12" Type Rs in my car, sealed boxes, around 1.5 cu.ft. each, driven with about 600W each. I'm very happy with the results.
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