Hi,
Originality in my book is learning from the masters and then putting your own
take on the compromises they have made, personally for me whilst happy to
exploit all the hard work other people have done I'd always change a few
things related to my personal take on the compromises.
What I would not do is ignore all the hard work they have done for originality.
They have done loads of things you need to do, use the information. e.g.
if you and a friend bought the same motorbike and he had it tuned and
tested to good effect, if you had it tuned would you also have it tested ?
These people are your friends, and the more you find out about loudspeaker
design you'll find originality is rare, and ignorance commonplace, it is the case
nearly everything sensible has been thought of / done before by someone.
If you want to work this out on your own fair enough, but the sensible and
to me intelligent take advantage of all the help they can get, and that
means for me for most basing your design on known good principles.
I built several speakers in my youth and did not really learn a lot other
than about the building process, they were wrong and are still wrong.
Your questions seem niave, why sealed ? When vented IMO would be
clearly better (unless unstated a subwoofer is involved). The point
is nowadays you can learn far more from others than by yourself.
Originality is cool when there is nothing wrong with it, but
unless its thought through to a master level there usually is.
I'd like to able to design an F1 car, I cannot, if I got a job for a a team
at the bottom of the grid, all they would be asking me about is what
are those bits on the cars at the front doing ? Cannot answer that
then I'm out of a job, they would not care about my "originality".
😎 /Sreten.
http://sites.google.com/site/undefinition/diy
http://www.zaphaudio.com
http://www.rjbaudio.com/
http://speakerdesignworks.com/
http://www.htguide.com/forum
http://www.humblehomemadehifi.com
http://www.troelsgravesen.dk/
http://www.linkwitzlab.com/
http://www.musicanddesign.com/
Originality in my book is learning from the masters and then putting your own
take on the compromises they have made, personally for me whilst happy to
exploit all the hard work other people have done I'd always change a few
things related to my personal take on the compromises.
What I would not do is ignore all the hard work they have done for originality.
They have done loads of things you need to do, use the information. e.g.
if you and a friend bought the same motorbike and he had it tuned and
tested to good effect, if you had it tuned would you also have it tested ?
These people are your friends, and the more you find out about loudspeaker
design you'll find originality is rare, and ignorance commonplace, it is the case
nearly everything sensible has been thought of / done before by someone.
If you want to work this out on your own fair enough, but the sensible and
to me intelligent take advantage of all the help they can get, and that
means for me for most basing your design on known good principles.
I built several speakers in my youth and did not really learn a lot other
than about the building process, they were wrong and are still wrong.
Your questions seem niave, why sealed ? When vented IMO would be
clearly better (unless unstated a subwoofer is involved). The point
is nowadays you can learn far more from others than by yourself.
Originality is cool when there is nothing wrong with it, but
unless its thought through to a master level there usually is.
I'd like to able to design an F1 car, I cannot, if I got a job for a a team
at the bottom of the grid, all they would be asking me about is what
are those bits on the cars at the front doing ? Cannot answer that
then I'm out of a job, they would not care about my "originality".
😎 /Sreten.
http://sites.google.com/site/undefinition/diy
http://www.zaphaudio.com
http://www.rjbaudio.com/
http://speakerdesignworks.com/
http://www.htguide.com/forum
http://www.humblehomemadehifi.com
http://www.troelsgravesen.dk/
http://www.linkwitzlab.com/
http://www.musicanddesign.com/
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I'm with sreten here, go vented to get the best out of your woofer.
Re: 'I built several speakers in my youth and did not really learn a lot ' - at least you had a go, if you'd listened to some old grump saying 'you can't do that' you'd have acheived nothing....
Re: 'I built several speakers in my youth and did not really learn a lot ' - at least you had a go, if you'd listened to some old grump saying 'you can't do that' you'd have acheived nothing....
I just ran a simulation and came up with great results for a vented box. I suppose the reason I hadn't thought of it first was namely because a sealed enclosure was far more common in the literature I am reading.
Here's what I've come up with in regards to the vented box. It looks great, I'm decently skilled with woodworking, so this should be an interesting project in that regard.
That's with one port at 9.20 cm. According to this though, the enclosure will have to be much bigger, with a recommended volume of 115.3 L. Is that correct? Again, is there a recommended way to distribute the speaker size or is it acceptable to just make a 15 x 20 x 23in enclosure?
Also, in regards to originality, I didn't necessarily mean a completely original design, but rather I reached the conclusion myself. It's the DIY ethic, after all.
Here's what I've come up with in regards to the vented box. It looks great, I'm decently skilled with woodworking, so this should be an interesting project in that regard.
An externally hosted image should be here but it was not working when we last tested it.
That's with one port at 9.20 cm. According to this though, the enclosure will have to be much bigger, with a recommended volume of 115.3 L. Is that correct? Again, is there a recommended way to distribute the speaker size or is it acceptable to just make a 15 x 20 x 23in enclosure?
Also, in regards to originality, I didn't necessarily mean a completely original design, but rather I reached the conclusion myself. It's the DIY ethic, after all.
I guess you and I will have to agree to disagree here, 🙂. If you have any more suggestions, I'd still love to hear them though.
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Hi Zafsk, the comment on the sensitivity was in the context of making it easy to do the crossover 🙂 using an lpad will bring down the levels, but obviously if an lpad can be avoided you have less components in your crossover and therefore less things to get wrong or interfere with your driver 🙂
Tony.
Tony.
Hi,
It is very different now, back then nobody knew anything, and I knew far
more than most - which really was not a lot - so you went with that flow.
That is not the way to do it nowadays IMO, alright building stuff and then
realising you've screwed it up later keeps the flame burning, maybe perhaps
I should shut up and let everyone screw up for the benefit of the cause.
😉 /Sreten.
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In terms of the enclosure dimensions. Try to avoid any dimensions being the same (i.e don't make a square box) or exact multiples of each other as this is likley to increase the chance of resonance.
The front dimensions are a matter of what you want to optermise. Some people believe the baffle should be as wide as practicable to reduce the frequency at which the speaker changes from radiating into half the space to all of the space (the response drops by 6dB as this occurs over a fairly wide frequency range). However others would say that you want this to happen as early as possible to improve the dispersion into the room and that you should make the cabinet as thin as possible then correct for the 6dB drop off.
Another camp says that you can never get this right because speakers don't radiate into a space like an instrument and the space you are listening to is a combination of the recorded space and the room you are in. In this camp there are two further options; those that would say you should create a CD design (Constant or Controled directivity) to isolate the listening room as much as possible or those that would say that using psychoacoustic principals the best approach is to make a speaker that has the same dispersion characteristic as a human voice (as the human mind is best adapted to post processing this to remove room effects) and so you should attempt to use a tweeter that is semi horn loaded and a narrow cabinet to make an analogue of the human head.
I realise this dosen't actually help you make a decision but it does high light the choices. For a first design I wouldn't get too wound up about this and you could just go with a bit wider than the bass driver as most people don't like really wide speakers and tall enough to put the tweeter at ear hight when sitting on your sofa then calculate the depth to enclose enough volume. So long as there is at least 20cm behind the back of the drive unit you shoudln't get too much trouble with refections off the back of the box.
I do recomend using the FRD tools BSC program you just need a copy of excell to run it up in and then you can put the dimensions in and the locations of the drive units and it will simulate the on axis difraction and baffle step effects, I found it really interesting that by just moving the tweeter a few CM of the central axis you can significantly reduce diffraction and with not much time you can significantly improve the likely response of the speaker.
As you have now seen with the box bass simulator a simulation can help to investigate different options without spending ages building the box.
Regards,
Andrew
The front dimensions are a matter of what you want to optermise. Some people believe the baffle should be as wide as practicable to reduce the frequency at which the speaker changes from radiating into half the space to all of the space (the response drops by 6dB as this occurs over a fairly wide frequency range). However others would say that you want this to happen as early as possible to improve the dispersion into the room and that you should make the cabinet as thin as possible then correct for the 6dB drop off.
Another camp says that you can never get this right because speakers don't radiate into a space like an instrument and the space you are listening to is a combination of the recorded space and the room you are in. In this camp there are two further options; those that would say you should create a CD design (Constant or Controled directivity) to isolate the listening room as much as possible or those that would say that using psychoacoustic principals the best approach is to make a speaker that has the same dispersion characteristic as a human voice (as the human mind is best adapted to post processing this to remove room effects) and so you should attempt to use a tweeter that is semi horn loaded and a narrow cabinet to make an analogue of the human head.
I realise this dosen't actually help you make a decision but it does high light the choices. For a first design I wouldn't get too wound up about this and you could just go with a bit wider than the bass driver as most people don't like really wide speakers and tall enough to put the tweeter at ear hight when sitting on your sofa then calculate the depth to enclose enough volume. So long as there is at least 20cm behind the back of the drive unit you shoudln't get too much trouble with refections off the back of the box.
I do recomend using the FRD tools BSC program you just need a copy of excell to run it up in and then you can put the dimensions in and the locations of the drive units and it will simulate the on axis difraction and baffle step effects, I found it really interesting that by just moving the tweeter a few CM of the central axis you can significantly reduce diffraction and with not much time you can significantly improve the likely response of the speaker.
As you have now seen with the box bass simulator a simulation can help to investigate different options without spending ages building the box.
Regards,
Andrew
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