Well, heres the deal, after building a few massive 12" subs, and selling most of them, ive decided that i want to try and make a very small subwoofer - 8". I would like it to be able to go fairly deep 25-30hz, and play fairly loud. Now, im not expecting anything like my dual tempest sonotube, but I do want the bass to be tight, which will make up for the lack of volume. How small can I get the box before i need serious eq, and what 8" sub is fairly tight with a large xmax? Thanks for your help.
Greg
Greg
I built a ported 25L sub a couple of years ago for a friend, and used the Audax HM210ZO. This was before I could measure things properly, and I was working on trial, error and experience, but the box sounded quite good, very tight, and I guess it went down to about 35Hz.
I think the Fs was about 30hz, and the Xmax was about 5mm, so as long as it was used at reasonable volumes I think you would be ok to do a bit of EQing on it. I assume you are thinking of the Linkwitz Transform circuit for this purpose?
I think the Fs was about 30hz, and the Xmax was about 5mm, so as long as it was used at reasonable volumes I think you would be ok to do a bit of EQing on it. I assume you are thinking of the Linkwitz Transform circuit for this purpose?
well, maybe
I might use the linkwitz transform for this purpose, but i would like to use it in moderation if i do. I sorta wanted it to be sealed, but i dont think i can acheive the output i am thinking of from such a small sub without being ported. The sid you mention sounds ok, but i was hoping to find something with lots of xmax in order to help kick out the notes. something about 8.5mm one way xmax would be nice, if such a beast exists for a resonable price.
Thanks
Greg
Are there any 8" subs with a long one way xmax? resonablly priced?
I might use the linkwitz transform for this purpose, but i would like to use it in moderation if i do. I sorta wanted it to be sealed, but i dont think i can acheive the output i am thinking of from such a small sub without being ported. The sid you mention sounds ok, but i was hoping to find something with lots of xmax in order to help kick out the notes. something about 8.5mm one way xmax would be nice, if such a beast exists for a resonable price.
Thanks
Greg
Are there any 8" subs with a long one way xmax? resonablly priced?
No idea.
You may find a car type sub that will do this though, but beware, the Audax specs are real, and the specs of car audio stuff may well have been massaged by the marketing types.😉
You may find a car type sub that will do this though, but beware, the Audax specs are real, and the specs of car audio stuff may well have been massaged by the marketing types.😉
well, im changing the funds now
Ive decided to drop this project in light of a new subwoofer i have just seen - this http://www.adireaudio.com/diy_audio/drivers/adire/tumult.htm they call it the tumult, which by the way means the massive commotion caused by a crowd. Over 34 mm of ONE WAY EXCURSION!!!!! and for only $500, i gotta drop all of my other projects and save for this!!! I am thinking that sonotube will not be enough. Well, i would still like to know if there are any long throw 8" subs in existance, but thatnks anyways.
Greg
The tumult will be mine, maybe two. mwahahahahahahaha
And heres a theoritical question: In small subs like the bob carver subs, they have a pr on the side opposite of the driver. Well would it work to make a similar design but replace the pr with yet another sub and have them wired out of phase (electrically)? This way, the air inside would not be compressed ever, and the subs should act like they are in an infinite baffle situation.(maybe?) The subs would be mechanically in phase, it would be just like having a powered pr to say.
Ive decided to drop this project in light of a new subwoofer i have just seen - this http://www.adireaudio.com/diy_audio/drivers/adire/tumult.htm they call it the tumult, which by the way means the massive commotion caused by a crowd. Over 34 mm of ONE WAY EXCURSION!!!!! and for only $500, i gotta drop all of my other projects and save for this!!! I am thinking that sonotube will not be enough. Well, i would still like to know if there are any long throw 8" subs in existance, but thatnks anyways.
Greg
The tumult will be mine, maybe two. mwahahahahahahaha
And heres a theoritical question: In small subs like the bob carver subs, they have a pr on the side opposite of the driver. Well would it work to make a similar design but replace the pr with yet another sub and have them wired out of phase (electrically)? This way, the air inside would not be compressed ever, and the subs should act like they are in an infinite baffle situation.(maybe?) The subs would be mechanically in phase, it would be just like having a powered pr to say.
I'm currently building a compact sub for my PC sound system. I'm using the 8" Peerless 831858 from Madisound which is on sale for $27.50 yet has an Xmax of 7mm. Here's the URL (look near the bottom):
http://www.madisound.com/sale.html
Madisound claim f3 = 45Hz in 15l ported but I'm using in 26l sealed, purely because a box of that size is already available.
I don't have the figures with me, but this driver in a 26l sealed box has an f3 of somewhere near 50Hz. I will be using a Linkwitz Transform to boost the low end to 20Hz, or possibly 30Hz if power & excursion are a problem. There's a very useful LT spreadsheet here:
http://www.pvconsultants.com/audio/eq/linktran.htm
Nice one,
David.
http://www.madisound.com/sale.html
Madisound claim f3 = 45Hz in 15l ported but I'm using in 26l sealed, purely because a box of that size is already available.
I don't have the figures with me, but this driver in a 26l sealed box has an f3 of somewhere near 50Hz. I will be using a Linkwitz Transform to boost the low end to 20Hz, or possibly 30Hz if power & excursion are a problem. There's a very useful LT spreadsheet here:
http://www.pvconsultants.com/audio/eq/linktran.htm
Nice one,
David.
I have built 3 subs with Linkwitz Transformers, and tried various -3db points on each of them, but they sounds much better with ordinary active crossovers.
Problems with the subs I built with Linkwitz Transformers:
-The bass is kind og "one tone", some frequencies are very powerful and many other are not.
-The bass is delayed in proportion to the mids and highs.
I have checked the transformers, and there is no errors in them (that I see)...
I have also tried different amps, including Electrocompaniet, but no good.
The sound can impress some people, but it`s not realy "HiFi"...
Just my 2 cents
🙂
Problems with the subs I built with Linkwitz Transformers:
-The bass is kind og "one tone", some frequencies are very powerful and many other are not.
-The bass is delayed in proportion to the mids and highs.
I have checked the transformers, and there is no errors in them (that I see)...
I have also tried different amps, including Electrocompaniet, but no good.
The sound can impress some people, but it`s not realy "HiFi"...
Just my 2 cents
🙂
2002tii (nice motor),
Here's my opinion on a couple of your points:
"The bass is kind og "one tone", some frequencies are very powerful and many other are not."
I would say that is almost certainly due to room modes and you noticed it because the Linkwitz transfom boosted the bass to the area where these modes can be excited. Running stereo subs and using notch filters to remove the peaks would help here.
"The bass is delayed in proportion to the mids and highs."
True, but the delay is very small, certainly no worse than the delays produced by a ported box. A simulation of my planned subs showed less than 20ms of delay at 10Hz, and around 5ms of delay at audible frequencies (30Hz -> 60Hz).
Nice one,
David.
Here's my opinion on a couple of your points:
"The bass is kind og "one tone", some frequencies are very powerful and many other are not."
I would say that is almost certainly due to room modes and you noticed it because the Linkwitz transfom boosted the bass to the area where these modes can be excited. Running stereo subs and using notch filters to remove the peaks would help here.
"The bass is delayed in proportion to the mids and highs."
True, but the delay is very small, certainly no worse than the delays produced by a ported box. A simulation of my planned subs showed less than 20ms of delay at 10Hz, and around 5ms of delay at audible frequencies (30Hz -> 60Hz).
Nice one,
David.
The efficiency in the mid-band range (ie unboosted) is unchanged fro the driver's spec. The efficiency drops as you enter into the equalised area because you're dumping more power into the driver to compensate for it's roll-off. This limits how load the transformed driver will play before you hit it's Xmax limit.
Nice one,
David.
Nice one,
David.
I don't know of a single driver that will do what you want without being incredibly inefficient. If you did find one, I would think the distortion at higher volumes would be to high to deem acceptable.
In my opinion you should look into the Peerless XLS 10" driver with the 400g passive radiator.
In my opinion you should look into the Peerless XLS 10" driver with the 400g passive radiator.
Yeah, that`s a nice car!
My 2002 is in pieces waiting to come back as a "race" car, nowadays I drive a 1988 M3 Evo2 (23/500)
Thats really a fun car to drive 😀
Back to the subject:
It could well be room modes, but we tried them in 2 different rooms as well.
We also tried with a cheap 12" and some expensive 8" Seas Excel, same result both sounded much better with ordinary active filter.
Of course they played deeper bass with the Linkwitz transformer, but quality goes before quantity i my book.
And the difference wasn`t that big (in a smal room)
The delay is enough to sense that the sub not are in time with the rest.
When we raised the -3db from 20Hz to 32Hz and changed the Q factor from 0.8 to 0.7 things got alot better but still, ordinary active filter sounded better.
I guess I could have tried a few more different filter settings and tuned the room, but I changed my B&W Matrix 805 to B&W Matrix 801 instead😎
My 2002 is in pieces waiting to come back as a "race" car, nowadays I drive a 1988 M3 Evo2 (23/500)
Thats really a fun car to drive 😀
Back to the subject:
It could well be room modes, but we tried them in 2 different rooms as well.
We also tried with a cheap 12" and some expensive 8" Seas Excel, same result both sounded much better with ordinary active filter.
Of course they played deeper bass with the Linkwitz transformer, but quality goes before quantity i my book.
And the difference wasn`t that big (in a smal room)
The delay is enough to sense that the sub not are in time with the rest.
When we raised the -3db from 20Hz to 32Hz and changed the Q factor from 0.8 to 0.7 things got alot better but still, ordinary active filter sounded better.
I guess I could have tried a few more different filter settings and tuned the room, but I changed my B&W Matrix 805 to B&W Matrix 801 instead😎
Re: well, im changing the funds now
No, you can't do that, unfortunately. They're actually out of phase. Which direction they're facing isn't relevant to whether they're out of phase or not, only whether or not they're firing into or out of the enclosure at the same time. By wiring them the way you suggest, you're correct in that there will be no pressure in the box, but there will be no pressure in the room as well, and no sound.
(well, in reality there will still be some sound out of it, but the out of phase drivers will cancel quite well and you'll be far worse off than if you just had the one driver)
There's no free lunch. 🙂
kingfootga said:
No, you can't do that, unfortunately. They're actually out of phase. Which direction they're facing isn't relevant to whether they're out of phase or not, only whether or not they're firing into or out of the enclosure at the same time. By wiring them the way you suggest, you're correct in that there will be no pressure in the box, but there will be no pressure in the room as well, and no sound.
(well, in reality there will still be some sound out of it, but the out of phase drivers will cancel quite well and you'll be far worse off than if you just had the one driver)
There's no free lunch. 🙂
If I were to build as sub like that (8", small box) I would definetly go with the MCM driver 55-2421. 16mm X-max is RESPECT! You could make it flat downto 20 Hz with Linkwitz correction and still get some decent SPL.....IN A 12L BOX!.
I have done a few boxes like this for the Tangband W8-740C which is the same as the MCM driver with some minor differences. And the best part is the little devil's cheap. $30 each is peanuts.
/Frez
I have done a few boxes like this for the Tangband W8-740C which is the same as the MCM driver with some minor differences. And the best part is the little devil's cheap. $30 each is peanuts.
/Frez
well, in that case.....
Well, seeing that that subwoofer is 8" has a super long throw, and is only $30, i think i can spare $100 and build it into a supersmall sub. Originally, i was thinking that i would need at least $250 to do this, because i thought the driver would be very expensive, but this should do very well! Ill buy it as an xmas present to myself. Now, how small can i make the box? I am thinking a 10" cube would be real nice. I dont have the ability to run any box simulation software ( i have linux), so i need to find a website with some. How much delay would there be if i used a linkwitz transform, and ported the box? Thanks for your help and enthusiasm. Its nice to see a post thats not about a huge sub every once in a while.
Greg
P.s. - i am in the midst of finishing off a custom ultra cheap sound system install in my sister's car, and out cheap reciever has no way of reducing bass out put independently of the sub output, so the speakers are distorting while trying to pump out low notes. How can i make an ultra simple (preferably one component) bass decreaser for each of the speakers? Just a gentle roll off starting at about 60hz for the rears, and 90hz for the fronts. Thanks a bunch.
Well, seeing that that subwoofer is 8" has a super long throw, and is only $30, i think i can spare $100 and build it into a supersmall sub. Originally, i was thinking that i would need at least $250 to do this, because i thought the driver would be very expensive, but this should do very well! Ill buy it as an xmas present to myself. Now, how small can i make the box? I am thinking a 10" cube would be real nice. I dont have the ability to run any box simulation software ( i have linux), so i need to find a website with some. How much delay would there be if i used a linkwitz transform, and ported the box? Thanks for your help and enthusiasm. Its nice to see a post thats not about a huge sub every once in a while.
Greg
P.s. - i am in the midst of finishing off a custom ultra cheap sound system install in my sister's car, and out cheap reciever has no way of reducing bass out put independently of the sub output, so the speakers are distorting while trying to pump out low notes. How can i make an ultra simple (preferably one component) bass decreaser for each of the speakers? Just a gentle roll off starting at about 60hz for the rears, and 90hz for the fronts. Thanks a bunch.
MCM 8"
I looked at the MCM 8" to possibly do something similar to what what kingfootga is trying but when I used the Linkwitz spreadsheet I had a hard time finding a suitable configuration. Best I could come up with was a box around .5 cuft and that required capacitor of 14uf or so which for some reason I thought was larger than recommended.
I looked at the MCM 8" to possibly do something similar to what what kingfootga is trying but when I used the Linkwitz spreadsheet I had a hard time finding a suitable configuration. Best I could come up with was a box around .5 cuft and that required capacitor of 14uf or so which for some reason I thought was larger than recommended.
daatkins said:
I'm curious to know how you are connecting your speakers to the PC. Is it via a receiver, 1/8" headphone->RCA cable or, are you building your own amplifier and such?
Oh god no
There is no way that i would ever connect my computer to my stereo system by an analogue cable, the sound cards just dont sound good enough. I have a Gamesurround Fortissimo II digital out to my minidisc deck (Sony MDS-JE320) and from there digital coax to my reciever. From there, the outputs (line level RCA) to five homemade 100watt amps, with a 500 watt amp for the current sub. I know its not optimal to use a reciever as a preamp, but it sounds good, and it gives me 5x100watt channels to experiment with new speakers with. Computer soundcards never have good bass output, nor do they have very good highs, they are always full of distrtion or not present, unless u get a really expensive sound card.
Greg
Any ideas on the simple bass blockers? (scroll up)
There is no way that i would ever connect my computer to my stereo system by an analogue cable, the sound cards just dont sound good enough. I have a Gamesurround Fortissimo II digital out to my minidisc deck (Sony MDS-JE320) and from there digital coax to my reciever. From there, the outputs (line level RCA) to five homemade 100watt amps, with a 500 watt amp for the current sub. I know its not optimal to use a reciever as a preamp, but it sounds good, and it gives me 5x100watt channels to experiment with new speakers with. Computer soundcards never have good bass output, nor do they have very good highs, they are always full of distrtion or not present, unless u get a really expensive sound card.
Greg
Any ideas on the simple bass blockers? (scroll up)
Bose(o),
The Peerless driver I'm using has dual voice coils and I'll be driving them with an LM3886 per coil. My PSU has +/- 34v so thats about 70W per coil. My simlations show that my limit is about 95dB @ 30Hz before I hit Xmax. I'll connect from the line-out.
The front L/R and rear L/R will have a TDA2050 each, which is good for around 20 -> 30W per channel....
Kingfoogta,
I agree that most sound cards aren't great for Hifi. This is purely in preperation for Doom3! My original design is....
http://www.apcl43.dsl.pipex.com/dinker.htm
... and this project is to improve on it's shortcomings.
Nice one,
David.
The Peerless driver I'm using has dual voice coils and I'll be driving them with an LM3886 per coil. My PSU has +/- 34v so thats about 70W per coil. My simlations show that my limit is about 95dB @ 30Hz before I hit Xmax. I'll connect from the line-out.
The front L/R and rear L/R will have a TDA2050 each, which is good for around 20 -> 30W per channel....
Kingfoogta,
I agree that most sound cards aren't great for Hifi. This is purely in preperation for Doom3! My original design is....
http://www.apcl43.dsl.pipex.com/dinker.htm
... and this project is to improve on it's shortcomings.
Nice one,
David.
- Status
- Not open for further replies.