It seems to play down to 25 Hz louder than a BR of the same size (Free Speaker Plans - Free Speaker Plans ? View topic - Cubo 18). How is the sound quality of these horns or distortion? I was originally looking to build a TH with two CSS SDX10 drivers, but some one wrote their horn was "ringing."
Free Speaker Plans - Free Speaker Plans ? View topic - Cubo Sub
Cubo Sub
I would like to build a cubo sub with a RCF L18P200-N. I don't know if a driver with such a low fs will play lower in a cubo or just quieter. Maybe I can change the shape of the cubo, to a longer horn (25 Hz perhaps). I haven't figured out how to use hornresp yet, though.
Free Speaker Plans - Free Speaker Plans ? View topic - Cubo Sub
Cubo Sub
I would like to build a cubo sub with a RCF L18P200-N. I don't know if a driver with such a low fs will play lower in a cubo or just quieter. Maybe I can change the shape of the cubo, to a longer horn (25 Hz perhaps). I haven't figured out how to use hornresp yet, though.
maybe try one of these in a cubo sub:
http://www.mcmelectronics.com/product/MCM-AUDIO-SELECT-55-2985-/55-2985
cheap enough and if you buy 2 you get free shipping!
http://www.mcmelectronics.com/product/MCM-AUDIO-SELECT-55-2985-/55-2985
cheap enough and if you buy 2 you get free shipping!
The Cubo is a variant of the tapped horn type of sub, the Cubo has a larger throat which works as a band pass.
The band pass probably reduces some of the objectionable upper peaks that are common for TH designs. I have not heard this particular TH, nor seen any measured response curves.
Distortion will be lower for a given SPL with TH compared to BR (bass reflex) of a similar size, but higher for a given excursion.
TH sound different than FLH (front loaded horns) or BR, sort of "in between" the two.
Good punch, but not as wide of a range of frequencies that sound good as BR or FLH.
That's a nice sub driver for home use. It has lowish Fs (for an 18" PA driver)but efficiency wise that's partially compensated for by higher Vas (and medium Qts). As a side note: Cubo Sub is also designed to fit 21" drivers but at 480 mm width that's not a good fit
If you send an e-mail to questionsaboutcubo[at]gmail[dot]com, I can see if it's possible to mod Cubo Sub to go lower and fit the dimension you mentioned. The depth/height up to 1215 mm and small width favor such a modification.
Most if not any sub horns (of all kinds) tend to have a particular sound in the mid bass area.
Best regards Johan
I haven't decided on a woofer yet. I also like the Eighteen Sound 18LW1400 because of the weather protected cone and double demodulation rings (I'm not sure if other 18" pro drivers have these).
I'm also looking at the P Audio C18-650EL because it's cheap, but I don't know how it compares to the RCF or 18 Sound or the almighty JBL (2242).
I also bought two Peerless XLS 830500 subs, but I don't think they will be as loud as one 18" in a horn and I think these high excursion subs produce quite a bit more distortion, but I am not sure. The only up side they would have is the box would be 1/2 to 1/3 of the size.
The cones in home subwoofers seem to be more ridged, but the voice coils are small. And they need to move a lot to be loud.
I also thought about building a TH with one or two CSS SDX10 subs. Some already did this, but they wrote it was "ringing." Oh, I already wrote this
I'm also looking at the P Audio C18-650EL because it's cheap, but I don't know how it compares to the RCF or 18 Sound or the almighty JBL (2242).
I also bought two Peerless XLS 830500 subs, but I don't think they will be as loud as one 18" in a horn and I think these high excursion subs produce quite a bit more distortion, but I am not sure. The only up side they would have is the box would be 1/2 to 1/3 of the size.
The cones in home subwoofers seem to be more ridged, but the voice coils are small. And they need to move a lot to be loud.
I also thought about building a TH with one or two CSS SDX10 subs. Some already did this, but they wrote it was "ringing." Oh, I already wrote this
That's rough. I can't really imagine anything having more distortion than a BR. For a given SPL it's less though, so that's good.
The cubo seems to play down to 25 Hz. That's should be plenty good for me, I think. I can't find the graph, but the cubo sub is louder than a BR above 25 Hz.
I wanted to build a Thor subwoofer, but it won't be loud enough. I like home subwoofer cones but not the motors. And pro subwoofers, I like the motors, but not the cones.
A given driver size driven with a given frequency to a certain amount of excursion will be as loud as any other (be it home or pro audio). I suspect you're getting more extension out of the home subwoofers, so they're using up their excursion going lower.
1) Are you sure you want to go to 25Hz for bass guitar?
2) how loud does this need to be?
... and just because one subwoofer is louder than another at a certain frequency, it doesn't mean either should be used that low: you may find excursion gets silly for relatively little output. Remember these are pro audio subwoofers: going loud is the primary design goal.
Chris
I'm going to go with two Peerless XLS 12" (830500) in about 3 cu. ft. (88 liters) volume sealed. I will be running of of my computer so my EQ opinions are for all practical purposes infinite. I can't have 12 cu. ft. or even 8 in my bedroom. I don't know why I have these crazy ideas sometimes.
2 Peerless should max SPL level should be 105 dB at 25 Hz at 1 meter in anechoic chamber. Not sure though. Here's a link:
SubZero, a Peerless 12 inch XLS based subwoofer
and
THOR - subwoofer
2 Peerless should max SPL level should be 105 dB at 25 Hz at 1 meter in anechoic chamber. Not sure though. Here's a link:
SubZero, a Peerless 12 inch XLS based subwoofer
and
THOR - subwoofer
The THOR ‘s output at Xmax (typically 10 % distortion) is only about 55 dB in the low B range of a bass guitar.
That is barely audible.
A pair of the SubZero can do about 105 dB at 25 Hz, which sounds to the ear about like 70 dB in the 1000 Hz range, around conversational level.
Seems like you have lowered the SPL bar quite a bit
.
The ported 18" pro subs you mentioned are not tuned anywhere near 25 Hz, the cone will flap at moderate power when used that low, and have hardly any fundamental output.
To get good VLF output in a BR cabinet requires a speaker with an FS near the Fb.
For low frequency response in a fairly small box (22.5 x 22.5 x 26.5 with a recessed grill) a pair of Eminence Lab 12 will give you 112 dB at 20 Hz, compared to only 96 dB from the Sub Zero.
A 16 dB difference at 20 Hz is huge, down that low a 5 dB difference sounds twice as loud, compared to a 10 dB difference at 1K sounds twice as loud.
I use the same size box tuned to 36 Hz, which gives a F3 of 30.6 Hz, and stronger output (about 125 dB) at 40 Hz, but only 106 dB at 20 Hz.
One of those dual 12" boxes can put out more 40 Hz than two Meyers 650P dual 18" cabinets, which take up about four times the space and use a lot more power.
Art Welter
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I would suggest the RSS315HO-4 You'll save ~100$ and get a Qtc above .5 in 3ft^3 With two drivers. Then later if you wanted to build a really good BR box You'd have a monster.
I never even looked at the specs for the HO. I just assumed the sound quality would be worse than the HF. I never thought it was designed for a smaller box volume. I already have two Peerless XLS 830500's. Which I actually like a little better. They have lower mms and Qts, but BL is almost as high as the Dayton HO. But it's good to know that I can replace them with Dayton HO in the future if I wanted to. Only the bolt holes are 2.5 mm closer to center in the Dayton.
I was thinking of using the RCF . . . 200-N, it has an fs of 26 Hz.
I'm not a fan of foam surrounds, even though I know that's kind of dumb. Maybe I can port the Peerless subs I have. I'm not crazy about the sound of ported drivers though. I've never seen any one post a phones (spelling?) and SPL vs frequency scale on DIY audio.
I'm a fan of good sound, which can be achieved with a variety of cone materials and surrounds that are appropriate for the speaker design.
Not a fan of rotting foam, but that seems to be a thing of the past, some of my Lab 12s have seen 10 years of PA use with no surround deterioration.
Below are magnitude and phase response charts of Sony 7506 headphones (7506Phones) and Lab 2x12" in a 36Hz Fb box(RawLab2x12) , and the same speakers with the ports sealed (Raw2x12iB).
Ported vs sealed is a trade off of LF volume vs transient response, though the LF phase response of the studio standard 7506 phones is somewhere between the BR and sealed Lab 12 response.
As you can see in the magnitude response chart, the Lab 2x12" Fb 36 box has as much as 6 dB more LF output than the same box sealed (IB) down to just below the low B on a 5 string bass guitar.
It takes four times the power at 40 Hz (low E on a four string bass) for the sealed box to achieve the same level as the BR, but the excursion at that level (assuming the speaker wouldn't burn up, and have extreme power compression as it actually would) would make the sealed box distort like a pig.
To maintain good impact, a sub must be matched in phase response to the top cabinet at the crossover point. The phase response down low, around Fb, is not nearly as critical in terms of sound quality.
To my ear, I generally prefer the clean LF output a BR offers over the "transient perfect" but low output level a sealed box can have.
That said, for my home stereo, where I generally don't listen above 100 dB, a pair of sealed 12" are adequate down to 20 Hz.
Art
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That is good to know. I've been avoiding foam surrounds like the plague.
I've read that below a certain frequency (say 30 Hz) you can't tell the difference in transient response between a sealed vs a ported enclosure, although a ported is 2 to 3 times worse.
I hear ya. I've spent a lot of time thinking about this.
It's just for my small bedroom. I should have built a 3-way with two 8 inch woofers, but the woofers I was looking at needed a lot of space. Also I lived in an apartment at that time and couldn't play my speakers that loud. Sometimes I think about building a new 3-way, but I think it would be easier and make more sense just to build a small subwoofer.
I seem to be very sensitive to transient response. Probably not possible, I'm not sure.
My ScanSpeak 21W/8555-01 have excellent transient response when listening to some content and then other content seems not so good. But they are hooked to my computer so it's hard to say what is causing it. I should do some more listening maybe.
I would be nice to read an A-B study about whether people can tell if they are listening to ported subs or sealed subs.
I think I'm going to put two Peerless 830500 drivers in a roughly 21" cube ported subwoofer. A Thor subwoofer should be that large anyway. The ports will be slotted MDF ports wrapping around four sides of the enclose (1x18 inches) with a ~2.39" (might have to be a little bigger) radius hole at the top going from the enclosure out, exiting on the bottom out of a ~2.39" (I might make it much larger) radius hole. Both holes will have 1.5" radius chamfers. The bottom will have tear drops with the point of the tear facing the port so to keep the area of the port roughly the same as it flows from under the subwoofer (the subwoofer will sit right on the ground). The two remaining sides will have the woofers on them. I'm not sure any one can picture this. Also I'm not sure why I've never seen an enclosure made like this. Seems hella elegant and sh1t as they say in LA 
I'm assuming the MJK ported worksheet is assuming that the port take up the volume of the dimensions (LxHxW) specified. Is this true?
For example: if I have an enclosure dimension of 12" cubed and a port with unknown dimensions, I would have 1 cu. ft. of volume minus the volume of the air contained in the port?
I'm assuming the MJK ported worksheet is assuming that the port take up the volume of the dimensions (LxHxW) specified. Is this true?
For example: if I have an enclosure dimension of 12" cubed and a port with unknown dimensions, I would have 1 cu. ft. of volume minus the volume of the air contained in the port?
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Below 25Hz and 30ms of delay the perception is negligible as the only thing you have to tell if the sound is behind is the 1st harmonic which is below 50hz.
In contrast if you have a BR box tuned to 50hz and the kick drum is tuned to 60hz with the first harmonic at 120 you will notice the ~35ms delay a lot. With the right driver in the right sized box (I use a sealed box volume Qtc ~.5) tuned very low (12-16hz) the speaker will sound like a sealed box down to ~30hz, then shifting to the Qp as the port couples to the box volume.
The pic below is the group delay for the rss315hf-4 in the same box volume one ported one sealed. I happen to have this design sitting in front of me and it sounds great.
edit: sorry you can't see the Hz at the bottom of the graph, the far left is 10Hz, 30hz is where they are 1ms apart.
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