It may not be the best way to get the volume and power handling I need for my new party system but is there a lot of destructive interference when using more than the normal 4 woofers in a bass bin?
While I am still looking for one of them I have (or should have) 6 of these cheap 12 inch woofer and No I haven't tested them and I have lost the factory parameters but they need about 120/150 litres per woofer for any depth of bass.
My last bass box got seriously over driven at a summer BBQ and I do not want to replicate the highly tuned ported box.
I can build a box 1200*1200 and 600 deep from 2 sheets of chipboard and fit 4 woofers. 6 woofers will take another sheet and add some extra complexity.
Either box will be wired series/ parallel
So opinions and comments please.
Bin will be on locking castors (Saved from the last box) and drag handles and all the usual stuff for better movement
While I am still looking for one of them I have (or should have) 6 of these cheap 12 inch woofer and No I haven't tested them and I have lost the factory parameters but they need about 120/150 litres per woofer for any depth of bass.
My last bass box got seriously over driven at a summer BBQ and I do not want to replicate the highly tuned ported box.
I can build a box 1200*1200 and 600 deep from 2 sheets of chipboard and fit 4 woofers. 6 woofers will take another sheet and add some extra complexity.
Either box will be wired series/ parallel
So opinions and comments please.
Bin will be on locking castors (Saved from the last box) and drag handles and all the usual stuff for better movement
I see no problems with interference occuring, but that rather depends on the crossover point between the woofers and the next driver(s).
Highly tuned ported boxes are okay, but (as always with any resonant enclosure) add a low cut filter a little below Fb - that way, cone excursion won't be a concern.
Highly tuned ported boxes are okay, but (as always with any resonant enclosure) add a low cut filter a little below Fb - that way, cone excursion won't be a concern.
Well bi-amping and crossing to the separate mid-tops around an octave above box resonance, say 150/180hz.
Trouble with the high tuned bass is most of our party music is bass heavy and contains lots of tones around 22-35 and the old boxes were half an octave or more higher ( kick-drum higher) than that, use the bass cut and we can't dance LOL, us oldies like tympany bass guitar and Taiko
Trouble with the high tuned bass is most of our party music is bass heavy and contains lots of tones around 22-35 and the old boxes were half an octave or more higher ( kick-drum higher) than that, use the bass cut and we can't dance LOL, us oldies like tympany bass guitar and Taiko
22-35.... what makes you think so? Most pop music has big boom-boom emphasis far higher. Practically nothing but very exceptional organ music and catastrophe movie sounds that low, no matter what you may hear rumored.
A good way to protect drivers is with a sealed box that provides inherent negative feedback on cone motion. Or with electronics with serious bass cut-off at maybe 30 Hz (which impairs nothing audible in the music), not the 15 Hz gradual cut-offs meant for LP records.
Using many cheap drivers in one box gives pretty much the same sound as one cheap driver. Like that idea? Except larger power handling. Betcha you can do better by making a few boxes to spread around (which is called "distributed"sound in the PA crowd).
Ben
A good way to protect drivers is with a sealed box that provides inherent negative feedback on cone motion. Or with electronics with serious bass cut-off at maybe 30 Hz (which impairs nothing audible in the music), not the 15 Hz gradual cut-offs meant for LP records.
Using many cheap drivers in one box gives pretty much the same sound as one cheap driver. Like that idea? Except larger power handling. Betcha you can do better by making a few boxes to spread around (which is called "distributed"sound in the PA crowd).
Ben
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Who said anything about POP music?
Rock and Roll and Electronica plus Classical
Pop music sucks
Low deep synthesised bass is common on albomost all of our collection.
I asked this question about building techno capable speakers and I personally was surprised to find that some of my collection was considered to be in this genre, I just call it "Chill-out'
Because most of the "electronica " uses synthesisers and the music does go that low, and that is what I play at parties also organ music.
Just accept this is what I want to do and answer my question if you wish to help.
Yes I want to reproduce notes lower than the Fs of the driver, but that has never been a problem for a sealed box in my experience.
Fs of the driver is 30Hz BTW.
Cheap does not mean bad, usually just lower excursion, which is why I need to use multiple drivers for the SPL I want.
So 4 drivers OK Yes?
6 drivers OK or bad?
Rock and Roll and Electronica plus Classical
Pop music sucks
Low deep synthesised bass is common on albomost all of our collection.
I asked this question about building techno capable speakers and I personally was surprised to find that some of my collection was considered to be in this genre, I just call it "Chill-out'
Because most of the "electronica " uses synthesisers and the music does go that low, and that is what I play at parties also organ music.
Just accept this is what I want to do and answer my question if you wish to help.
Yes I want to reproduce notes lower than the Fs of the driver, but that has never been a problem for a sealed box in my experience.
Fs of the driver is 30Hz BTW.
Cheap does not mean bad, usually just lower excursion, which is why I need to use multiple drivers for the SPL I want.
So 4 drivers OK Yes?
6 drivers OK or bad?
Well I may finally have to finally make an amplifier, but I can find 2 or 300 watts.
These woofers only have 6mm X-Max ( well 7 if I include the usual allowance ) so probably 50 watts each will overdrive them.
These are for BBQs so plenty of room outside for them (and the wheels will make moving them easy )
These woofers only have 6mm X-Max ( well 7 if I include the usual allowance ) so probably 50 watts each will overdrive them.
These are for BBQs so plenty of room outside for them (and the wheels will make moving them easy )
Moondog55,
I think that most people would agree that you can't possibly hear anything in the frequency range that you are trying to reproduce, whether that is a real pipe organ or a synthesizer. So you are really trying to produce a vibration that you can feel and nothing more. At that point distortion of the waveform will not matter it is not detectable to our ears. Since that is your baseline for this application why try and use limited excursion devices? Excursion is what you are after, though yes given enough drivers you can produce a given SPL level. So you can figure that it is going to take two 12" cones to move as much air as one 15" cone at the same excursion and 4 twelves to equal one 18" cone. Why not just buy some cheap 18" cones and make things simpler for yourself in amplifier count and all the associated electronics. Even simple passive crossovers at this frequency are going to cost in inductors. I am in agreement with Moondog that you could probably make as much of an impression with a real strong output at 35hz if it was punchy. At that frequency I can make your shirt shake or anything else you are wearing and you would feel the punch in your gut. Actually one good 15" speaker on a long bass horn could do what you are after. Much cheaper and more efficiently. Just an opinion from a newbie on the site..
I think that most people would agree that you can't possibly hear anything in the frequency range that you are trying to reproduce, whether that is a real pipe organ or a synthesizer. So you are really trying to produce a vibration that you can feel and nothing more. At that point distortion of the waveform will not matter it is not detectable to our ears. Since that is your baseline for this application why try and use limited excursion devices? Excursion is what you are after, though yes given enough drivers you can produce a given SPL level. So you can figure that it is going to take two 12" cones to move as much air as one 15" cone at the same excursion and 4 twelves to equal one 18" cone. Why not just buy some cheap 18" cones and make things simpler for yourself in amplifier count and all the associated electronics. Even simple passive crossovers at this frequency are going to cost in inductors. I am in agreement with Moondog that you could probably make as much of an impression with a real strong output at 35hz if it was punchy. At that frequency I can make your shirt shake or anything else you are wearing and you would feel the punch in your gut. Actually one good 15" speaker on a long bass horn could do what you are after. Much cheaper and more efficiently. Just an opinion from a newbie on the site..
Each time cone area is doubled sensitivity is raised by 3 dB, so 6 low frequency speakers will give you about 7.5 dB more output with the same power as one.
At 20 Hz, a 5 dB increase in level sounds twice as loud, 7.5 dB is a big deal.
The more low frequency speakers, the better, though keeping the output within 1/4 wavelength at the upper frequency can be a problem with multiple driver cabinets.
If you have the space and don't mind using a lot of wood, a tapped horn can give an additional 6 dB output over a bass reflex. With 6 drivers available, you could go for a tuning as low as 20 Hz and still get a lot of output.
I recently built a TH for my backyard using very cheap 10" speakers, the sensitivity outdoors equals the sensitivity of a pair of sealed 12" in the living room with nearly the same frequency response down to 30 Hz.
Bentoronto,
I hope I wasn't sounding Surly or condescending in my response. That wasn't my intention. I was simply trying to understand what the function of this barbeque speakers intention was. It didn't sound like this was intended as an outside hifi system, more of an effects application to get people up and dancing. I may not appreciate this music myself, perhaps if I was still young enough to be going to a dance club, but I thought that I understood the point of the exercise. I can get into that low bass when listening to a strong kick drum or even a pipe organ or the cannon sounds on a soundtrack. But it just seems like there are easier ways to achieve the end result. When I'm in a movie I'm not going to complain that the low bass is only going down to 30hz, some theaters even have shakers under the seats, that is an effect, I'm not listening to music though.
I hope I wasn't sounding Surly or condescending in my response. That wasn't my intention. I was simply trying to understand what the function of this barbeque speakers intention was. It didn't sound like this was intended as an outside hifi system, more of an effects application to get people up and dancing. I may not appreciate this music myself, perhaps if I was still young enough to be going to a dance club, but I thought that I understood the point of the exercise. I can get into that low bass when listening to a strong kick drum or even a pipe organ or the cannon sounds on a soundtrack. But it just seems like there are easier ways to achieve the end result. When I'm in a movie I'm not going to complain that the low bass is only going down to 30hz, some theaters even have shakers under the seats, that is an effect, I'm not listening to music though.
Hi Moondog55,
Post #1: "...a box 1200*1200 and 600 deep..."
Post #6: "... sealed box..."
Without knowing the data for the speakers: your basic box is about 400L; that should be enough for six, it may even be larger than optimum as you are dealing with a smallish Xmax, so you might want the box volume to control the driver excursion. Sealed boxes are just not the ideal starting point for extra low outdoor bass, and without the driver data (or the location data) the only other thing I can tell you is that "destructive interference" should not be a problem.
Regards,
Post #1: "...a box 1200*1200 and 600 deep..."
Post #6: "... sealed box..."
Without knowing the data for the speakers: your basic box is about 400L; that should be enough for six, it may even be larger than optimum as you are dealing with a smallish Xmax, so you might want the box volume to control the driver excursion. Sealed boxes are just not the ideal starting point for extra low outdoor bass, and without the driver data (or the location data) the only other thing I can tell you is that "destructive interference" should not be a problem.
Regards,
Spoken like someone who has never listed to music with bass notes below 30Hz on speakers that can reproduce it
You can count me out of "most people" in your sweeping generalisation.In my last house I had speakers with an in room bass response that was flat down to 24Hz, and like Moondog55 I often also listen to Electronica with synthesised bass notes and I can assure you categorically that not only is there plenty of music in that genre (and some others) that has real content well below 35Hz, but it is VERY audible as a tone if your speakers can produce it. It's not just a vibration that you feel, although that is part of the experience as well.
Now that I'm in a much smaller house with a smaller system that only goes down to about 35Hz I really miss the lower notes on some of my music...
On the contrary, distortion becomes more noticeable at very low frequencies because our sensitivity to bass drops off rapidly at lower frequencies, (especially at lower SPL) thus the harmonics sound disproportionately stronger compared to the fundamental. Likewise a speaker trying to produce bass below its useful range will often be putting out more harmonics than fundamental, making the situation worse...
So to reproduce clean very low bass notes you do actually need quite low distortion.
I have to agree with this. Too many small drivers never works as well as one or a few larger drivers. It's not just about cone area, its about coupling the air, excursion, power handling and sensitivity and so on. I wouldn't be building a sub with lots of 6" drivers, especially one to go down into the low 20Hz range...
A "real strong output" at 35Hz is just going to have a one note bass boom. That doesn't sound anywhere near as good as a bass response that actually extends well below 35Hz, when playing music that includes such low notes...
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Not to get flamed anymore here, but I doubt very much that what you are calling hearing a 20Hz sound is what you are describing. You may very well feel it and I wouldn't doubt that for a minute that you can feel that frequency but hear that I don't think so. I'd postulate that what you are hearing is not the fundamental frequency but higher frequency harmonics of that tone. Not that it is music but if you played just a simple tone from a tone generator I doubt very much that you hear the fundamental, but you can sure feel it. I am not an audiologist but I don't think that is true. Go ahead and flame me, I can take it..... You can sure watch a cone move at that frequency if you don't tear it apart, but hear a true fundamental 20hz.........
Please read what I said again, I never said 20Hz, I said 24Hz. Below 24Hz doesn't sound like a tone to me (more like a pressure wave) but 24Hz and up definitely does.
I strongly suggest that you build some speakers that can produce low frequencies like that at low distortion levels before speculating on what it sounds like or whether it's audible. The fact that you're disputing it in the first place makes it clear that you haven't heard such a system. I have, many times, and yes I have listened to sine waves from a generator at those frequencies as well.
It's not even necessary to feel the vibrations on your body - many good quality in ear earphones can go down to just below 25Hz as well, and it still sounds like a tone. Actual in room bass is a more visceral experience due to the vibration of your body as well, but that doesn't change the tonality of it.
Bass notes down to about 24Hz or so are very real, very audible with sufficient SPL, have a definite pitch, and can be heard perfectly well without the help of any harmonics. They are anything but inaudible.
I strongly suggest that you build some speakers that can produce low frequencies like that at low distortion levels before speculating on what it sounds like or whether it's audible. The fact that you're disputing it in the first place makes it clear that you haven't heard such a system. I have, many times, and yes I have listened to sine waves from a generator at those frequencies as well.
It's not even necessary to feel the vibrations on your body - many good quality in ear earphones can go down to just below 25Hz as well, and it still sounds like a tone. Actual in room bass is a more visceral experience due to the vibration of your body as well, but that doesn't change the tonality of it.
Bass notes down to about 24Hz or so are very real, very audible with sufficient SPL, have a definite pitch, and can be heard perfectly well without the help of any harmonics. They are anything but inaudible.
Wrong. Two coincident sound sources combine to + 6dB. Coincident in practice means they need to be closer than a 1/4 wavelength apart and are fed with an identical signal. Therefore, adding drivers increases efficiency and that is how large systems can top 50%.
Problem with cheapo drivers is that they typically have either high Vas - so you need an enormous enclosure - or high Fs.
vac
Not so fast.
Two coincident sound sources, for example two identical woofers also require twice the drive power of a single woofer. The SPL increases 6dB but the power input increases 3dB as well - eg drivers in parallel draw twice the power of a single driver.
The sensitivity increase per watt is only 3dB.
Actually a large array of woofers cannot reach 50% in practice, let alone top it. The reasons why are too complex to delve into in this thread but it's something that speaker dave has provided some good references to in other threads...
Basically some simplifying assumptions are made about how drivers sum together in space which no longer hold when you have a physically huge array of drivers, all of which conspires to to make the maximum efficiency asymptotic well below 50% for arrays of direct radiators.
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But feeling the bass in my innards is exactly what I would like to try and do and I want to get as close as possible.
Perhaps I should buy some large excursion 15, 18 or even 21inch woofers but I have to use what I have.
What I have are these cheap 12inch woofers and I only have 6 of them.
Interestingly SWMBO was critiquing the latest 3-Way build and her comment on the bass in those "I can't feel the low notes like with our bedroom speakers ) so even my beloved wants the bass low.
Perhaps I should buy some large excursion 15, 18 or even 21inch woofers but I have to use what I have.
What I have are these cheap 12inch woofers and I only have 6 of them.
Interestingly SWMBO was critiquing the latest 3-Way build and her comment on the bass in those "I can't feel the low notes like with our bedroom speakers ) so even my beloved wants the bass low.
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