Big is relative. My project, based on the Dayton Quatro in a tl is tuned somewhere around 15 hz in a box 18x17.5x85. It's big but only takes up a bit more than 2 sq feet of floor space. I am hoping for 90 db at 1 watt, more with small room and corner loading.
Dayton drivers have pretty low fs values, but 18 is about as low as they are going to get. There are some drivers (Peerless) with over 400 grams of moving mass and fs closer to 10 but that is pretty extreme, the drivers are not large and probably very expensive and not readily available.
Why not large drivers if the box will be big anyway? Because the box for the bigger driver will be exponentially larger, that's why. You might want to look into IB as well, using a whole adjacent room as your box.
Dayton drivers have pretty low fs values, but 18 is about as low as they are going to get. There are some drivers (Peerless) with over 400 grams of moving mass and fs closer to 10 but that is pretty extreme, the drivers are not large and probably very expensive and not readily available.
Why not large drivers if the box will be big anyway? Because the box for the bigger driver will be exponentially larger, that's why. You might want to look into IB as well, using a whole adjacent room as your box.
I heard of someone who has built a subwoofer in a big concrete smoke canal, intended as exhaust for heating, in his living room! I think he used at that time the oval Kef driver, and a diy transistor amp.
I have a 15 inch driver and want to try this http://sound.westhost.com/project48.htm with it. As mentioned in post 13.
here it is (bit dark)
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Cloth Ears, I had not before heard of the two organs you mention. I am sure about Radio City and Wannamakers. These both have web pages.
64' is rare. It is a big deal, a giant motor.
I'm not sure that it really is sound or makes music. But I suspect it could. I'd like to experiment. Of course, it won't make highly rythmical music. But I think it could make ambient music.
Thanks
64' is rare. It is a big deal, a giant motor.
I'm not sure that it really is sound or makes music. But I suspect it could. I'd like to experiment. Of course, it won't make highly rythmical music. But I think it could make ambient music.
Thanks
tubee, I also have though of using things like fire places. If you want infra base, being built in is nice. Doesn't have to go thru doorways. No real weight limit. Could be concrete, could be stucco.
I have heard that in England there are houses built with base horns where the floor joins to a wall?
I have heard that in England there are houses built with base horns where the floor joins to a wall?
Steve Callas
I'm really interested to know more about what you built. Do I understand that that is a tuned port base reflex?
So does the driver fire down, from the bottom. Is it really a cylinder?
Where is the port, on the top? What is it all made of?
I clicked on your link. It seems to be a big web site. I can't find anything about your project.
What exactly is the graph you've posted. An actual speaker range measurement at 10hz would be real tough. You would have to do it outdoors?
If it is impedance, another matter.
How can you go below fs without eq? Are you saying its just the enclosure? This I do not understand. Its a steep roll of at fs.
What do you do with a 10hz capability?
I'm really interested to know more about what you built. Do I understand that that is a tuned port base reflex?
So does the driver fire down, from the bottom. Is it really a cylinder?
Where is the port, on the top? What is it all made of?
I clicked on your link. It seems to be a big web site. I can't find anything about your project.
What exactly is the graph you've posted. An actual speaker range measurement at 10hz would be real tough. You would have to do it outdoors?
If it is impedance, another matter.
How can you go below fs without eq? Are you saying its just the enclosure? This I do not understand. Its a steep roll of at fs.
What do you do with a 10hz capability?
zenmasterbrian said:
The 32”Clarion I have is an SRW 8000.
Te published TSP are Fs: 17Hz/Qts: 0,4/ Vas: 312,9l
Power 1000W 300W continues - 97dB/W/m
I found it in a little PA store in Den Haag. The just used it as decoration.
Normal price is about 2800 euro’s (I paid less)
I do not know if it is made by Misubishi (but my car is)
The driver frame is very strong aluminium cast frame. No problems with it.
My enclosure is just an open baffle like my normal speakers. (I use 6 Db/octave EQ correction starting at 18 Hz.)
I’m driving it with a Denon POA 6600A amp. (260 W at 8 ohm)
At the moment my audio equipment is in storage
with all my furniture because I am moving from Heerhugowaard to Den Haag. But it is worth waiting for because I get an dedicated Audio room 5,5m * 5,5m * 2,6m zen, yes, it is a ported subwoofer - downfiring driver on the bottom, port on top. The enclosure is a cylinder made from a 28" diameter concrete form, generically known as Sonotube. It is rigid cardboard in the form of a cylindrical shell. Wall thickness is about 1/3". The port is also made from Sonotube - it's wall thickness is about 1/4". The benefits of a "sonosub" are its weight, small footprint, no need for internal bracing, and due to its shape, you can normally get away with larger ports than you would in a box enclosure of the same volume.
The graph I posted is my in room frequency response from 10-100hz. The large low tuned design results in an anechoic FR that has a very slight rolloff beginning at 50hz, much less steep than a sealed design. The 4th order rolloff doesn't start until ~12.5hz. In room, the room gain meshes very well with such a shaped FR and gives me the flat response you see to at least 10hz, possibly a bit lower.
The steep 4th order rolloff you are referring to in a ported design does not occur at driver Fs, it occurs just below the enclosure tuning. The trick is to find a driver that can "hold it's own" as deep as possible so that you can get away with a very low tune. The Avalanche 18 does just that, and still provides big time output. I could have used a smaller enclosure, higher tune, and more power to easily reach 120db+ levels from this single driver sub, but that's not what I was after. I traded some headroom for extension - now I'm flat to 10hz in room with 115db+ capability.
You'd be surprised how many movies nowadays have bass tracks that extend into the single digit frequencies. If you want the full bass experience, subs that will get you to 20hz just don't cut it anymore, not in my opinion at least.
The graph I posted is my in room frequency response from 10-100hz. The large low tuned design results in an anechoic FR that has a very slight rolloff beginning at 50hz, much less steep than a sealed design. The 4th order rolloff doesn't start until ~12.5hz. In room, the room gain meshes very well with such a shaped FR and gives me the flat response you see to at least 10hz, possibly a bit lower.
The steep 4th order rolloff you are referring to in a ported design does not occur at driver Fs, it occurs just below the enclosure tuning. The trick is to find a driver that can "hold it's own" as deep as possible so that you can get away with a very low tune. The Avalanche 18 does just that, and still provides big time output. I could have used a smaller enclosure, higher tune, and more power to easily reach 120db+ levels from this single driver sub, but that's not what I was after. I traded some headroom for extension - now I'm flat to 10hz in room with 115db+ capability.
You'd be surprised how many movies nowadays have bass tracks that extend into the single digit frequencies. If you want the full bass experience, subs that will get you to 20hz just don't cut it anymore, not in my opinion at least.
I don't do anything with 15 hz - the sub is not done yet. But this kind of thing is mostly for home theatre, lots of new movies have super low sections.
IB means infinite baffle, which is just a fancy word for a HUGE box, like an adjacent room, basement, attic, outside world, etc. Remember, the bigger the box, the lower the tuning.
You need to understand that drivers do perform below fs, they just do it better and louder above fs.
Get WinISD, it's a free and easy to use program with a good sized database of drivers. It is also a program that allows changes to be made, everything from changing the tuning of a box, adding volume to the box, adding weight to the driver, isobarik loading, etc.
With this tool you can pick any driver in the database, find out the size and tuning of the recommended enclosure, then change it however you want. Tune way below fs if you like. Add weight to the cone and lower fs. It's limitless. And you can graphically see what effect the changes are making.
WinISD will do sealed, ported and fourth order bandpass for you. Get a feel for that and then start researching transmission lines in this very forum. With a tl you can get the same response Steve is getting (flat to 10 hz) but hopefully with a bit more sensitivity. Note that tuning to get to 10 hz flat is going to hurt overall sensitivity a great deal but if you want to go low that's how to do it.
And finally realize that there is no trickery or magic at work here. It is very hard to find drivers with fs lower than 20 hz but people make enclosure of ALL TYPES that are tuned below 20 every day since the 1950's. What you need to do is spend a lot of time with WinISD and reading this forum looking for low tuned subs, there is so much info here alone that you can get lost for days.
IB means infinite baffle, which is just a fancy word for a HUGE box, like an adjacent room, basement, attic, outside world, etc. Remember, the bigger the box, the lower the tuning.
You need to understand that drivers do perform below fs, they just do it better and louder above fs.
Get WinISD, it's a free and easy to use program with a good sized database of drivers. It is also a program that allows changes to be made, everything from changing the tuning of a box, adding volume to the box, adding weight to the driver, isobarik loading, etc.
With this tool you can pick any driver in the database, find out the size and tuning of the recommended enclosure, then change it however you want. Tune way below fs if you like. Add weight to the cone and lower fs. It's limitless. And you can graphically see what effect the changes are making.
WinISD will do sealed, ported and fourth order bandpass for you. Get a feel for that and then start researching transmission lines in this very forum. With a tl you can get the same response Steve is getting (flat to 10 hz) but hopefully with a bit more sensitivity. Note that tuning to get to 10 hz flat is going to hurt overall sensitivity a great deal but if you want to go low that's how to do it.
And finally realize that there is no trickery or magic at work here. It is very hard to find drivers with fs lower than 20 hz but people make enclosure of ALL TYPES that are tuned below 20 every day since the 1950's. What you need to do is spend a lot of time with WinISD and reading this forum looking for low tuned subs, there is so much info here alone that you can get lost for days.
approx 1.30-1.27 euro to the US buck, right now.
2300 Euro, eagles approx. $2940US
Perry's Hemp cone (is it hemp? I dunno) Tsuzureko 25 is one way to go. IIRC, it has the Adire drive system. It's a big 'un!
Like all Adire motor'd drive units/designs, it tends to work well in smallish (comparitively speaking) sealed boxes.
http://www.hempacoustics.com/products.html
I've seen it in person and I can say it's defintely, at the very least an awesome looking driver and the specs don't hurt either. At full load, in an average living room, it does have the capacity to damage you.
(4ohm) 96db, 1w/1m, 28m p-p linear travel, 1000W nominal, 3000W peak. etc.
2300 Euro, eagles approx. $2940US
Perry's Hemp cone (is it hemp? I dunno) Tsuzureko 25 is one way to go. IIRC, it has the Adire drive system. It's a big 'un!
Like all Adire motor'd drive units/designs, it tends to work well in smallish (comparitively speaking) sealed boxes.
http://www.hempacoustics.com/products.html
I've seen it in person and I can say it's defintely, at the very least an awesome looking driver and the specs don't hurt either. At full load, in an average living room, it does have the capacity to damage you.
(4ohm) 96db, 1w/1m, 28m p-p linear travel, 1000W nominal, 3000W peak. etc.
SteveCallas, Thanks for the info. I'm aquainted with the concrete forms you describe. I did not know they were made that big. Your assembly must really be huge
I know the the Low Freq Effects signal on 5.1 DVDs does not have a minimum frequency limit. But it sounds like we are talking here about things like explosions.
I still question a frequency response measurement down to 10hz because of the long wavelengths. I feel it would more be a measurement of interaction with the room. Well, maybe that's all that matters in the long run.
I understand what you are saying about the bass reflex enclosure rolloff. It is really step. I know it does not happen at fs.
But, as you slew through fs, aren't there still problems, a need to use Eq? Isn't there a speaker impedance bump?
What do you think makes for a good speaker to use in such sub fs applications?
I know the the Low Freq Effects signal on 5.1 DVDs does not have a minimum frequency limit. But it sounds like we are talking here about things like explosions.
I still question a frequency response measurement down to 10hz because of the long wavelengths. I feel it would more be a measurement of interaction with the room. Well, maybe that's all that matters in the long run.
I understand what you are saying about the bass reflex enclosure rolloff. It is really step. I know it does not happen at fs.
But, as you slew through fs, aren't there still problems, a need to use Eq? Isn't there a speaker impedance bump?
What do you think makes for a good speaker to use in such sub fs applications?
just a guy
"With a tl you can get the same response Steve is getting (flat to 10 hz) but hopefully with a bit more sensitivity. Note that tuning to get to 10 hz flat is going to hurt overall sensitivity a great deal "
Could you explain the above more?
Do people commonly add weight to cones to lower fs. I've heard of painting them. Does this all work out?
Aren't there still problems with speaker rolloff and impedance bumps when going under fs.
I agree that this forum is filled with highly knowledgeable people. I already have had to expand my own thinking and am having a hard time assimilating it all. Thanks
"With a tl you can get the same response Steve is getting (flat to 10 hz) but hopefully with a bit more sensitivity. Note that tuning to get to 10 hz flat is going to hurt overall sensitivity a great deal "
Could you explain the above more?
Do people commonly add weight to cones to lower fs. I've heard of painting them. Does this all work out?
Aren't there still problems with speaker rolloff and impedance bumps when going under fs.
I agree that this forum is filled with highly knowledgeable people. I already have had to expand my own thinking and am having a hard time assimilating it all. Thanks
Usually you shouldn't have to add weight but it's an option.
You can tune any enclosure to any frequency. The lower you tune, the less loud it will be overall. In my very limited experience, for very low frequencies, tl's can be more sensitive (louder) than ported boxes at the same tuning.
What you need now is a very clear goal. Answer these questions and it will go a long way.
How big is the max size of box you can live with? (IB has no box size as it uses wall mount and an adjacent room.)
How many of them can you fit in your room? (Stereo subs are nice and quad are nicer but only one is necessary.)
What is the lowest and highest frequencies you want to reproduce?
What do you want the FR curve to look like?
How much do you want to spend? (Note that it does not have to be expensive.)
Start there and that will cut out lots of designs. For example, a horn that goes that low will not fit in your house. If your box has to be small, sealed with Linkwitz transform is the only way to go. Or just build a sub just like Steve's and prepare to get sick. Nausea is reported as a problem with the frequencies and SPL that thing is capable of producing.
No problems with impedance bumps or eq if designed properly - but sealed does need eq and lots of it and lots of power too.
You can tune any enclosure to any frequency. The lower you tune, the less loud it will be overall. In my very limited experience, for very low frequencies, tl's can be more sensitive (louder) than ported boxes at the same tuning.
What you need now is a very clear goal. Answer these questions and it will go a long way.
How big is the max size of box you can live with? (IB has no box size as it uses wall mount and an adjacent room.)
How many of them can you fit in your room? (Stereo subs are nice and quad are nicer but only one is necessary.)
What is the lowest and highest frequencies you want to reproduce?
What do you want the FR curve to look like?
How much do you want to spend? (Note that it does not have to be expensive.)
Start there and that will cut out lots of designs. For example, a horn that goes that low will not fit in your house. If your box has to be small, sealed with Linkwitz transform is the only way to go. Or just build a sub just like Steve's and prepare to get sick. Nausea is reported as a problem with the frequencies and SPL that thing is capable of producing.
No problems with impedance bumps or eq if designed properly - but sealed does need eq and lots of it and lots of power too.
Thanks Mike "Mashaffer" for correcting the photograph. I can do this too with Gimp (linux) but i didn't had the time for it.
Btw that woofer i had for free, i saved it from the trashbin, a bad connection to voice coil was the fault, it is repaired now.
I know someone who has a nonfunctional 2* 400W amp, if i can get it for a nice price and manage to repair it, could have (if the woofer is cooperative with its parameters) a very good sounding sub for allmost no $$. But first i have to make a deal with this guy. When this dead (PA) amp is functional again it should easy worth 1200 Euro. But the parts (output transistors?) weren't easy to find i heard.
Btw that woofer i had for free, i saved it from the trashbin, a bad connection to voice coil was the fault, it is repaired now.
I know someone who has a nonfunctional 2* 400W amp, if i can get it for a nice price and manage to repair it, could have (if the woofer is cooperative with its parameters) a very good sounding sub for allmost no $$. But first i have to make a deal with this guy. When this dead (PA) amp is functional again it should easy worth 1200 Euro. But the parts (output transistors?) weren't easy to find i heard.
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Add weight is an option to lower Fs but also efficiency decreases. Painting is not enough to increase weight.
A better option would be driving the speaker below Fs with a very high powered & active filtered amp to compensate the 12 dB roll-off when its mounted in a relatively small enclosure. (ELF)
My personal choice would be:
* As 1st choice a (very) large TL, and because its to big here in my home, i know then for sure i will have serious relational problems. Its only a humble 2,15 meters high. See: http://www.lautsprechershop.de/hifi/index.htm?/hifi/bau_vtls.htm
*2nd the ELF method, and i will try this with the 15 inch woofer, the method is mentioned earlier in post 13: http://sound.westhost.com/project48.htm A 60 Litres cabinet would do i think. And more room-mate friendly
Actually the LFE spec is 3hz-120hz as far as I am aware of. And ultra low bass is being used for a lot more than just explosions nowadays. You may want to peruse this thread
Not sure what you are getting at. However long or short the wavelength is, it still passes through my room and my seating position.
No, just as there isn't any need to use it above Fs. Fs is not the lowest frequency a driver can produce.
Not at my Fs.
For a large and low tuned ported design - high Vas, low Fs, high Vd, moderate Bl.
I'd like to clear a few things up here....
Using a driver below Fs is a very common thing(as well as tuning below Fs). The distortion skyrockets when you go below Fs... which is mostly why it is not reccomended(not sensitivity! if sensitivity were the real issue we wouldnt be using 86db @1W drivers in the first place!!!). Getting a flat response is also difficult, but there is EQ for that.
When you want low bass displacement is all that matters.
A 64' pipe may produce an audible sound, BUT dont forget that pipes have harmonic resonances also. You're probably not hearing a 8hz fundemental unless you're an elephant or whale.
Steve I'd like to experience your setup sometime and see just what the difference between 10hz and 16hz is. I've never noticed a difference in the feeling... 16hz is the high frequency limit of what is considered infrasound, so comparing 18hz and 10hz may yeild a significant difference... I dont know, maybe I'm just numb
As far as the Bag end subs go... They're flat to 8hz with 1watt imput. From what I understand their electronic alteration limits excursion when the power goes up. I dont think they're really after infrasonic output, rather they're after a time coherent output.
Someone mentioned measuring a 10hz SPL in room... This is not impossible. The sound pressure level is a measure of the RATE OF CHANGE of PRESSURE. Wavelength does not matter... You just need a microphone that is calibrated flat to 10hz and you can measure the 10hz SPL anywhere you want.
Using a driver below Fs is a very common thing(as well as tuning below Fs). The distortion skyrockets when you go below Fs... which is mostly why it is not reccomended(not sensitivity! if sensitivity were the real issue we wouldnt be using 86db @1W drivers in the first place!!!). Getting a flat response is also difficult, but there is EQ for that.
When you want low bass displacement is all that matters.
A 64' pipe may produce an audible sound, BUT dont forget that pipes have harmonic resonances also. You're probably not hearing a 8hz fundemental unless you're an elephant or whale.
Steve I'd like to experience your setup sometime and see just what the difference between 10hz and 16hz is. I've never noticed a difference in the feeling... 16hz is the high frequency limit of what is considered infrasound, so comparing 18hz and 10hz may yeild a significant difference... I dont know, maybe I'm just numb
As far as the Bag end subs go... They're flat to 8hz with 1watt imput. From what I understand their electronic alteration limits excursion when the power goes up. I dont think they're really after infrasonic output, rather they're after a time coherent output.
Someone mentioned measuring a 10hz SPL in room... This is not impossible. The sound pressure level is a measure of the RATE OF CHANGE of PRESSURE. Wavelength does not matter... You just need a microphone that is calibrated flat to 10hz and you can measure the 10hz SPL anywhere you want.
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