mashaffer
Xmax for this type of driver, short of the absolute limit of its Suspension before that tears or before the Voice-coil wire connection is broken - whichever occurs first ! - would have to be defined.
These stiff surround cones have very limited excursion with regard to the sound having whatever degree of Fidelity a plot of the driver's frequency response may suggest. Excursion beyond that and the cone rapidly goes into substantially greater break-up and subsequent distortions. Such is not necessarily a problem, as this is a sound that players of Electric-music instruments like, and likely you do - basically such creates another Tonal Dimension, preferred more for some instruments than others, and usually not too much for human voices -{except perhaps for Death Metal vocalists and similar !}.
That type of driver usually has sufficient cone-suspension extension to work beyond the pleasant aspects of "tonal dimension" before its voice-coil wire connections break, but do be careful ...
"vocal and acc" - is "acc" Acoustic Guitar, or Accordion ?
You can use a 16 ohm driver and an 8 ohm driver together, with a cross-over. Several Hi-Fi Speaker manufacturers currently make models with an 8 ohm driver and a 4 ohm driver.
If you want to do this, then post your idea here and I will comment further. I have done it myself to useful effect.
How-ever, as you have the 15" plus x-over plus the 6" x 9", then use those together for one purpose - {if your 6"x9" is working ?}, and use the 16 ohm driver as you intended as a floor monitor - it will likely have sufficient bandwidth to work OK for a vocal monitor, but it will be power and excursion limited thus not suited to very loud band.
It could be used with cross-over in its midrange and your 15" for the bass and low-mids to make a higher volume monitor.
If you need extra extension into the high treble, then one of the small horn-loaded Piezo-electric drivers can be added - I have seen and used several such combinations. Look for the 1005 piezo model of what was originally manufactured by "Motorola" and next by "CTS" and apparently now by a company in Asia somewhere.
There is a Thread somewhere in this Forum about Motorola 1005, or, CTS 1005, along with mention of some of the then other models and there may have been a Link there to a useful Applications sheet - I can remember some of it but not all of it.
Adding magnets may reduce Q and increase damping - I would have to try this and listen to hear if useful effect, but with this type of driver its voice-coil's heat capacity and mechanical capability of its suspesion would likely be exceeded before any significant "Higher efficiency" benefit could be achieved.
My recommendation to stuff the enclosure, and in the way I described, is to increase the damping/lower the Q - the sound absorption aspect of doing such is simply an additional benefit for this application as a vocal monitor.
The spelling of one product's name I mentioned is apparently "Accousta Stuf", and now as I spelt it in my first post.
My primary intention was to give advice about what can be achieved with a fairly cheap, non hi-fidelity, driver for which it is not likely to be cost effective to buy and add magnets nor make complicated enclosures.
Money spent on such things could be better spent on a modern technology higher excursion; higher efficiency; lower Q driver, which would be worth designing and building a sophisticated enclosure for - if your particular application requires such.
regards,
mashaffer said:
Xmax for this type of driver, short of the absolute limit of its Suspension before that tears or before the Voice-coil wire connection is broken - whichever occurs first ! - would have to be defined.
These stiff surround cones have very limited excursion with regard to the sound having whatever degree of Fidelity a plot of the driver's frequency response may suggest. Excursion beyond that and the cone rapidly goes into substantially greater break-up and subsequent distortions. Such is not necessarily a problem, as this is a sound that players of Electric-music instruments like, and likely you do - basically such creates another Tonal Dimension, preferred more for some instruments than others, and usually not too much for human voices -{except perhaps for Death Metal vocalists and similar !}.
That type of driver usually has sufficient cone-suspension extension to work beyond the pleasant aspects of "tonal dimension" before its voice-coil wire connections break, but do be careful ...
"vocal and acc" - is "acc" Acoustic Guitar, or Accordion ?
You can use a 16 ohm driver and an 8 ohm driver together, with a cross-over. Several Hi-Fi Speaker manufacturers currently make models with an 8 ohm driver and a 4 ohm driver.
If you want to do this, then post your idea here and I will comment further. I have done it myself to useful effect.
How-ever, as you have the 15" plus x-over plus the 6" x 9", then use those together for one purpose - {if your 6"x9" is working ?}, and use the 16 ohm driver as you intended as a floor monitor - it will likely have sufficient bandwidth to work OK for a vocal monitor, but it will be power and excursion limited thus not suited to very loud band.
It could be used with cross-over in its midrange and your 15" for the bass and low-mids to make a higher volume monitor.
If you need extra extension into the high treble, then one of the small horn-loaded Piezo-electric drivers can be added - I have seen and used several such combinations. Look for the 1005 piezo model of what was originally manufactured by "Motorola" and next by "CTS" and apparently now by a company in Asia somewhere.
There is a Thread somewhere in this Forum about Motorola 1005, or, CTS 1005, along with mention of some of the then other models and there may have been a Link there to a useful Applications sheet - I can remember some of it but not all of it.
Adding magnets may reduce Q and increase damping - I would have to try this and listen to hear if useful effect, but with this type of driver its voice-coil's heat capacity and mechanical capability of its suspesion would likely be exceeded before any significant "Higher efficiency" benefit could be achieved.
My recommendation to stuff the enclosure, and in the way I described, is to increase the damping/lower the Q - the sound absorption aspect of doing such is simply an additional benefit for this application as a vocal monitor.
The spelling of one product's name I mentioned is apparently "Accousta Stuf", and now as I spelt it in my first post.
My primary intention was to give advice about what can be achieved with a fairly cheap, non hi-fidelity, driver for which it is not likely to be cost effective to buy and add magnets nor make complicated enclosures.
Money spent on such things could be better spent on a modern technology higher excursion; higher efficiency; lower Q driver, which would be worth designing and building a sophisticated enclosure for - if your particular application requires such.
regards,
the Science ...
bjorno, I can appreciate the Science, but I was aiming to keep this project in perspective with mashaffer's particular driver, and its seeming low-budget application.
Also, theory is fine, but it works usually only well in the broad middle area of the Variance.
Drivers whose parameters are at one or other of the extremes behave some-what less than the, necessarily limited, mathematical equations would seem to indicate.
Kelticwizard has mentioned one aspect of such - the high Q.
Most of the published equations have some approximations within them and/or some supposedly insignificant factors ommitted, and that is fine for most domestic purposes, but here we have a driver which is seemingly going to be used in an enclosure in a Live Sound situation, ie: where there will be other significant, and perhaps dominant, sound sources which will impinge on the subject driver and its enclosure, thus the acoustic-mechanical effects of such impingements will have to be included in any equations for calculation of Aperiodic Damping where such is exposed to the acoustic environment, and similar for other types of exposed driver/enclosure loadings.
-
Please, can you post a Link to, or list References for Richard Small's methods -{is this in one of his JAES published papers ?}- and for "MJK :s program", as I had not known of this.
regards,
bjorno, I can appreciate the Science, but I was aiming to keep this project in perspective with mashaffer's particular driver, and its seeming low-budget application.
Also, theory is fine, but it works usually only well in the broad middle area of the Variance.
Drivers whose parameters are at one or other of the extremes behave some-what less than the, necessarily limited, mathematical equations would seem to indicate.
Kelticwizard has mentioned one aspect of such - the high Q.
Most of the published equations have some approximations within them and/or some supposedly insignificant factors ommitted, and that is fine for most domestic purposes, but here we have a driver which is seemingly going to be used in an enclosure in a Live Sound situation, ie: where there will be other significant, and perhaps dominant, sound sources which will impinge on the subject driver and its enclosure, thus the acoustic-mechanical effects of such impingements will have to be included in any equations for calculation of Aperiodic Damping where such is exposed to the acoustic environment, and similar for other types of exposed driver/enclosure loadings.
-
bjorno said:
Please, can you post a Link to, or list References for Richard Small's methods -{is this in one of his JAES published papers ?}- and for "MJK :s program", as I had not known of this.
regards,
MJK's program is by Martin J King, a group of MathCAD worksheets, (a usable MathCAD demo to use the sheets is free).
They are available at www.quarter-wave.com.
I have them, I love them, they are extremely useful. Unlike other programs, they do not rely on "lumped parameters", but instead compute the enclosure bit by bit. It calculates the differences in output from moving the driver on the baffle, moving the port on the baffle, (in some TL encosures these can make huge differences), and even where in the enclosure or port the stuffing goes, and how much in each inch of the TL line or port. It computes TL lines, closed and vented boxes, back loaded horns, and more.
Bjorno has already given us screenshots from the program in this thread.
They are available at www.quarter-wave.com.
I have them, I love them, they are extremely useful. Unlike other programs, they do not rely on "lumped parameters", but instead compute the enclosure bit by bit. It calculates the differences in output from moving the driver on the baffle, moving the port on the baffle, (in some TL encosures these can make huge differences), and even where in the enclosure or port the stuffing goes, and how much in each inch of the TL line or port. It computes TL lines, closed and vented boxes, back loaded horns, and more.
Bjorno has already given us screenshots from the program in this thread.
mistake
Hah, I should have re-read before I posted that !
There were two thoughts in my mind and I see I've jumbled both together ...
Any increase in Heat as result of adding magnets is likely to be very small, and perhaps insignificant.
"Higher Efficiency" would be useful if the amplifier being used is low power, though no Higher Volume - SPL - is likely to be achieved, owing to that driver type's voice-coil heat capacity and suspension limitations.
alan-1-b said:
Hah, I should have re-read before I posted that !
There were two thoughts in my mind and I see I've jumbled both together ...
Any increase in Heat as result of adding magnets is likely to be very small, and perhaps insignificant.
"Higher Efficiency" would be useful if the amplifier being used is low power, though no Higher Volume - SPL - is likely to be achieved, owing to that driver type's voice-coil heat capacity and suspension limitations.
to Kelticwizard and experimenting musos
Depending on where the voice-coil actually is when at rest position within :-
If it is at exact middle of the length of the cylinder, then possibly there would be less distortion product when it moves in and out of the added magnet end versus the still original amount of distortion produced when it moves far into the other end, thus this set-up may create another Tonal Dimension !
If one was lucky enough for the voice-coil to be off-centre towards the end you are re-inforcing, hey maybe you've got lucky for better linearity as well as better efficiency ! -{You may indeed be a Wizard !!}.
Umm, but if it was resting towards the other end ... well, further into the Tonal Dimension and perhaps too far, but hey, who can predict the sounds that some musos like and can find uses for ...
I do like your bar magnets around the outside and clamped on idea ! -{perhaps you really are a Wizard}.
With a speaker I liked the basic sound of but wanted to tighten up the bottom end and/or improve its transient response, I'd now be tempted to give this a try, thus I'll remember this - thankyou for the tip !
Tightening up and improving Transient Response does change the Tonal Dimension, thus warning to Electric Guitar players - you might not like this mod. Bass players - you might, and especially if you are attempting to drive an unsuitable speaker with a tube amplifier, but it would be worth the trouble only if the speaker cone has sufficient travel -{Xmax}- to be able to reproduce low frequencies at the required volume levels.
Thankyou for the Link to Martin J King's site - I had read of him elsewhere, but hadn't got around to looking for his site.
Thankyou also for describing the usefulness of his programs - it seems to be good stuff !
regards,
kelticwizard said:
Depending on where the voice-coil actually is when at rest position within :-
If it is at exact middle of the length of the cylinder, then possibly there would be less distortion product when it moves in and out of the added magnet end versus the still original amount of distortion produced when it moves far into the other end, thus this set-up may create another Tonal Dimension !
If one was lucky enough for the voice-coil to be off-centre towards the end you are re-inforcing, hey maybe you've got lucky for better linearity as well as better efficiency ! -{You may indeed be a Wizard !!}.
Umm, but if it was resting towards the other end ... well, further into the Tonal Dimension and perhaps too far, but hey, who can predict the sounds that some musos like and can find uses for ...
I do like your bar magnets around the outside and clamped on idea ! -{perhaps you really are a Wizard}.
With a speaker I liked the basic sound of but wanted to tighten up the bottom end and/or improve its transient response, I'd now be tempted to give this a try, thus I'll remember this - thankyou for the tip !
Tightening up and improving Transient Response does change the Tonal Dimension, thus warning to Electric Guitar players - you might not like this mod. Bass players - you might, and especially if you are attempting to drive an unsuitable speaker with a tube amplifier, but it would be worth the trouble only if the speaker cone has sufficient travel -{Xmax}- to be able to reproduce low frequencies at the required volume levels.
Thankyou for the Link to Martin J King's site - I had read of him elsewhere, but hadn't got around to looking for his site.
Thankyou also for describing the usefulness of his programs - it seems to be good stuff !
regards,
mashaffer - further to roll around in your mind ...
Given that the Wurlitzer spkr is only a 10" and of limited excursion and power handling capacity, use that for the vocal monitor and use the other channel of your amp to drive the 15" + 6"x9" for keyboard and tracks monitor.
You can still add a piezo tweeter horn with the 10" if required.
regards,
mashaffer said:
Given that the Wurlitzer spkr is only a 10" and of limited excursion and power handling capacity, use that for the vocal monitor and use the other channel of your amp to drive the 15" + 6"x9" for keyboard and tracks monitor.
You can still add a piezo tweeter horn with the 10" if required.
regards,
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