Hi everyone,
I need to build a sub (although it will have to work up to around 200Hz) to partner a front horn.
I was wondering if anyone could answer some of the questions I have about 'fast' bass. I've read the PDF by Adire Audio on inductance and subwoofer drivers, so I guess I should be looking for a driver with low inductance. I dont care about movies, this thing has to be able to do music.
I picked this up from another thread - the Audio Atlas 15 has a low inductance of 0.86mH - unfortunately I've never seen this driver and doubt its availible over here in the UK or EU. I was looking at an Adire Tempest 15D8, it has an inductance of 3mH per voice coil - this looks high, but would I be right in thinking that when both coils are wired in parallel the inductance would be just 1.5mH, which doesnt seem so bad.
Also the Tempest 15D4 has an inductance of 1.9mH per voice coil, so I assume that gives you an inductance of under 1mH with both coils in parallel (unfortunately I think this driver will kill my plate amp when wired in parallel).
I was looking at 15" PA drivers as these are reported to be fast and dynamic (well they play high anyway) but to my suprise the inductance of a Kappa Pro 15 LF for example is over 1mH, not much or any better than the previously mentioned subwoofer drivers appear (and doesnt go low in a sealed box either).
One last question - I've heard of people complaining about the Adire Shiva rolling off at higher frequancies because of its high inductance. Do you think this will be a problem for me with my target upper rolloff?
Cheers, Richard.
I need to build a sub (although it will have to work up to around 200Hz) to partner a front horn.
I was wondering if anyone could answer some of the questions I have about 'fast' bass. I've read the PDF by Adire Audio on inductance and subwoofer drivers, so I guess I should be looking for a driver with low inductance. I dont care about movies, this thing has to be able to do music.
I picked this up from another thread - the Audio Atlas 15 has a low inductance of 0.86mH - unfortunately I've never seen this driver and doubt its availible over here in the UK or EU. I was looking at an Adire Tempest 15D8, it has an inductance of 3mH per voice coil - this looks high, but would I be right in thinking that when both coils are wired in parallel the inductance would be just 1.5mH, which doesnt seem so bad.
Also the Tempest 15D4 has an inductance of 1.9mH per voice coil, so I assume that gives you an inductance of under 1mH with both coils in parallel (unfortunately I think this driver will kill my plate amp when wired in parallel).
I was looking at 15" PA drivers as these are reported to be fast and dynamic (well they play high anyway) but to my suprise the inductance of a Kappa Pro 15 LF for example is over 1mH, not much or any better than the previously mentioned subwoofer drivers appear (and doesnt go low in a sealed box either).
One last question - I've heard of people complaining about the Adire Shiva rolling off at higher frequancies because of its high inductance. Do you think this will be a problem for me with my target upper rolloff?
Cheers, Richard.
Hi,
regarding "fast" bass I'd ignore any article that grossly simplifies the issue.
You need a good bass driver, good to ~ 400Hz, not a subwoofer driver.
Presumably your going to have an active crossover ?
And much more bass amplifier power than horn amplifier power ?
If not your also going to need a high sensitivity driver.
Which will effectively preclude sealed box loading,
you'll need reflex for decent bass extension.
With a horn midrange/treble the most important capability for
the bass driver you should be looking at is low distortion.
As ever the bigger the driver usually the better.
/sreten.
regarding "fast" bass I'd ignore any article that grossly simplifies the issue.
You need a good bass driver, good to ~ 400Hz, not a subwoofer driver.
Presumably your going to have an active crossover ?
And much more bass amplifier power than horn amplifier power ?
If not your also going to need a high sensitivity driver.
Which will effectively preclude sealed box loading,
you'll need reflex for decent bass extension.
With a horn midrange/treble the most important capability for
the bass driver you should be looking at is low distortion.
As ever the bigger the driver usually the better.
/sreten.
Agree with all of sreten's comments.
'Fast' bass comes from more that just inductance, it the synergy of a load of factors.
Seems to me to be a bit bonkers trying to partner a box-loaded bass bin to a midrange horn. Bass is what eats watts and is where you need to concentrate on efficiency.
Are you wanting a PA or home application?
'Fast' bass comes from more that just inductance, it the synergy of a load of factors.
Seems to me to be a bit bonkers trying to partner a box-loaded bass bin to a midrange horn. Bass is what eats watts and is where you need to concentrate on efficiency.
Are you wanting a PA or home application?
Hi,
Sorry I failed to mention that it is active, I will be using this plate amp - link Which I have had modified so the filter is variable between 40-240Hz.
This is for home use.
I was previously going to use the Eminence Magnum 15LF as it seemed to fit my requirements perfectly however they decided to discontinue it in the EU, and to get it from the US would mean 33% tax ontop. So if anyone knows where i can get this over here, please let me know!
Here's a link to a rendering I did last week of how I hope my project to turn out - link
Thanks for the replys, Richard.
Sorry I failed to mention that it is active, I will be using this plate amp - link Which I have had modified so the filter is variable between 40-240Hz.
This is for home use.
I was previously going to use the Eminence Magnum 15LF as it seemed to fit my requirements perfectly however they decided to discontinue it in the EU, and to get it from the US would mean 33% tax ontop. So if anyone knows where i can get this over here, please let me know!
Here's a link to a rendering I did last week of how I hope my project to turn out - link
Thanks for the replys, Richard.
I see, interesting concept. I think there is another Loughborough student designing a speaker system on here, Matt somebody.
I assume the system is more for music than films? Just curious why you are going for horn mids. Also if you can give us a target low cutoff and box size it might be that there are other drivers that are suitable or even better than PA ones.
I assume the system is more for music than films? Just curious why you are going for horn mids. Also if you can give us a target low cutoff and box size it might be that there are other drivers that are suitable or even better than PA ones.
Hi, yes you're right, my friend Matt is also designing a speaker for his final year project
Yes this system is also intended more for music. The Horn has a cutoff of 150Hz, with decent output from about 204Hz (predicted). I have GRP'd one horn so far and given it a try and the 200Hz prediction seems about right.
I went for horn mids as I've experimented with the Fostex FE206e in a backhorn and liked the sound (after driver tweaks). Reviews of oris horns etc seem to indicate more of the same so I thought it'd be interesting and different (my lecturers certainly seem to think its different) to try out.
Once the driver I've brought to uni with me had warmed up the 1 front horn sounded very very promising, voices very much more real than I have experienced before, so I'm pleased and want to make sure I do a decent job of the bass unit.
I know I should've sorted it out months ago, but I thought I had with the Magnum 15LF, and have been messed around since october by a shop in London that had 'the only pair in the UK' - long story. Now it looks like these drivers are out of the window, so I really really need to find something else soon.
I have around 120-130L to play with and about 400UKP ~ $701.46 for a pair of bass drivers.
Yes this system is also intended more for music. The Horn has a cutoff of 150Hz, with decent output from about 204Hz (predicted). I have GRP'd one horn so far and given it a try and the 200Hz prediction seems about right.
I went for horn mids as I've experimented with the Fostex FE206e in a backhorn and liked the sound (after driver tweaks). Reviews of oris horns etc seem to indicate more of the same so I thought it'd be interesting and different (my lecturers certainly seem to think its different) to try out.
Once the driver I've brought to uni with me had warmed up the 1 front horn sounded very very promising, voices very much more real than I have experienced before, so I'm pleased and want to make sure I do a decent job of the bass unit.
I know I should've sorted it out months ago, but I thought I had with the Magnum 15LF, and have been messed around since october by a shop in London that had 'the only pair in the UK' - long story. Now it looks like these drivers are out of the window, so I really really need to find something else soon.
I have around 120-130L to play with and about 400UKP ~ $701.46 for a pair of bass drivers.
woofer inductance
Try peerless xls serise. Or better try some woofers rather than subwoofers. Decent woofers (10*2 or 12*1) can reach 30Hz easily.
Every manufacturer has some point to show off. Fast bass in case of subwoofers is basically meaning less. There is no fast bass. Actually its the matching of the woofer with the midrange which creates the sensation of fast bass or transients. The better the match the faster the bass it appears. Lower L helps but xbl tech. does not come cheap.
For a 4ohm woofer with 1mH inductance the impedance(Z) at 200Hz is about 5.256.
Z=R+2*3.1428*f*L if i can remember correctly.
Roughly speaking a 4ohm woofer would become 5.256ohm at 200hz.
Shiva has about 4.2mH per coil, and would cause some trouble at 200hz. But after all its a LCSG sub woofer.
Yes parall. coils reduces inductance by half.
Try peerless xls serise. Or better try some woofers rather than subwoofers. Decent woofers (10*2 or 12*1) can reach 30Hz easily.
Every manufacturer has some point to show off. Fast bass in case of subwoofers is basically meaning less. There is no fast bass. Actually its the matching of the woofer with the midrange which creates the sensation of fast bass or transients. The better the match the faster the bass it appears. Lower L helps but xbl tech. does not come cheap.
For a 4ohm woofer with 1mH inductance the impedance(Z) at 200Hz is about 5.256.
Z=R+2*3.1428*f*L if i can remember correctly.
Roughly speaking a 4ohm woofer would become 5.256ohm at 200hz.
Shiva has about 4.2mH per coil, and would cause some trouble at 200hz. But after all its a LCSG sub woofer.
Yes parall. coils reduces inductance by half.
Hmmm......
300w and 15" PA drivers, should be able to make your ears bleed.
The issue is what amplifier is to be used with mid/treble horn.
Usually this sort of speaker goes with a 3W - 5W single ended valve amp.
If this is the case then PA driver SPL capability might not be the issue,
and a hi-fi 15"driver (not many about) might be more suitable.
/sreten.
300w and 15" PA drivers, should be able to make your ears bleed.
The issue is what amplifier is to be used with mid/treble horn.
Usually this sort of speaker goes with a 3W - 5W single ended valve amp.
If this is the case then PA driver SPL capability might not be the issue,
and a hi-fi 15"driver (not many about) might be more suitable.
/sreten.The amp that will be used with the Horn will be (for now) my push pull 40wpc EL34 'thing'. One day, maybe in the not to distant future I'd like some 300B or 2A3 monoblocks.
And yes I'm not too concerned about SPL, its just the PA driver I was going to use was flat to 2 or 3khz and would give me -3db at 55Hz in a sealed box - with the shallow roll-off I thought that would be deep enough, if not, the plate amp is flexible as I can EQ the bottom end if needed. I'm also used to the FE206e in reccomended backhorn that arent well known for their earth shattering sub-sonic bass....
Richard.
And yes I'm not too concerned about SPL, its just the PA driver I was going to use was flat to 2 or 3khz and would give me -3db at 55Hz in a sealed box - with the shallow roll-off I thought that would be deep enough, if not, the plate amp is flexible as I can EQ the bottom end if needed. I'm also used to the FE206e in reccomended backhorn that arent well known for their earth shattering sub-sonic bass....
Richard.
http://www.precisiondevices.co.uk/ShowDetails.asp?id=17
This would do the trick, low inductance, high efficiency, linear FR.
This would do the trick, low inductance, high efficiency, linear FR.
Hi,
Yep it would, shame its 24" and over 500GBP EACH!
Why not? Just dont turn it up too loud.....
I agree it would be plenty loud enough, and would give you more extension than a more sensitive driver, unfortunately something of this specification seems hard to come by.
Fortunately for me, some of the original drivers I was going to get have come up on ebay! link, so I'll get a pair of them. They measure quite differently than 99% of PA drivers and are a fair bit less sensitive too. I dont know of anything that fits into what you described in the last post as well as this....
Richard.
Yep it would, shame its 24" and over 500GBP EACH!
Why not? Just dont turn it up too loud.....
I agree it would be plenty loud enough, and would give you more extension than a more sensitive driver, unfortunately something of this specification seems hard to come by.
Fortunately for me, some of the original drivers I was going to get have come up on ebay! link, so I'll get a pair of them. They measure quite differently than 99% of PA drivers and are a fair bit less sensitive too. I dont know of anything that fits into what you described in the last post as well as this....
Richard.
rabw said:
Hi,
I know I said you need a bass driver not a subwoofer, but I thinksome 15" car
subwoofers than are built pretty much as a normal bass driver might fit the bill.
Its simply a case of swapping ~ 10dB of senstivity for ~ an octave of bass.
And likely more absolute output capability for low bass (excursion) than a PA driver.
Here are the parameters of a relatively cheap 15 " car driver, the JBL gt4-15 :
Frequency Response 20Hz - 400Hz
Sensitivity 91dB
Impedance 4 Ohms
Vas 133 liter
Qts 0.44
Fs 28.36Hz
Qes 0.47
Qms 7.35
• Polypropylene woofer cone delivers exceptional attack resulting in incredibly tight bass response.
• Butyl rubber surrounds offer ideal cone-edge suspension and also guarantee long-term reliability by rejecting moisture and ultraviolet contamination.
• 12mm Linear one-way X-max and dual 40oz(80oz)magnets make this subwoofer a great choice for high output applications.
• Progressive spider provides better control at excursion limits than more commonly used linear spiders.
Power handling is 1000 of some form of watts, car drivers for you.
/sreten.
I dont like the tone of PP plastic in bass woofers, sorry but i dont, it reminds me cheap toys for some reason.
An 80 ounce magnet is good for a 2 inch coil, is the drive your talking using a 2 or 3 inch coil?
I know very little about loudspeakers design but what i think i almost kind of know is inductance increase above the fs of a woofer, so a woofer designed for LF will have high intermodulation at say 100 to 200Hz, anybody agree?
I am talking about a big drive unit with a low Fs in this case.
The Adire man maybe forgot to tell you is that a shorting ring will reduce inductance Le(x) above fs by making a counter flux, anybody agree?
Fast bass is more about the energy level of the music and the dynamics of the system, the ability to go from quiet to loud in a millisecond is what i think people call fast, but people look for superfical ways to discribe fast bass without any meantingful way of understand what fast is, somebody said bass is not fast or slow, I agree with that, bass is bass, if its X its X if its Y its Y, what you hear is what you hear, a speaker can not make **** up, it can only follow the input given to it.
You can't expect a heavy weight fighter (15 inch woofer) to match up well with light weight fighter(midrange horn) you need something inbetween or you have a miss match anybody agree?
The 15 can be PA but then you lose the drop zone, or you use a real LF woofer and you get a poor balance between the drive units, i suggest you try both and find out which one you like best.
An 80 ounce magnet is good for a 2 inch coil, is the drive your talking using a 2 or 3 inch coil?
I know very little about loudspeakers design but what i think i almost kind of know is inductance increase above the fs of a woofer, so a woofer designed for LF will have high intermodulation at say 100 to 200Hz, anybody agree?
I am talking about a big drive unit with a low Fs in this case.
The Adire man maybe forgot to tell you is that a shorting ring will reduce inductance Le(x) above fs by making a counter flux, anybody agree?
Fast bass is more about the energy level of the music and the dynamics of the system, the ability to go from quiet to loud in a millisecond is what i think people call fast, but people look for superfical ways to discribe fast bass without any meantingful way of understand what fast is, somebody said bass is not fast or slow, I agree with that, bass is bass, if its X its X if its Y its Y, what you hear is what you hear, a speaker can not make **** up, it can only follow the input given to it.
You can't expect a heavy weight fighter (15 inch woofer) to match up well with light weight fighter(midrange horn) you need something inbetween or you have a miss match anybody agree?
The 15 can be PA but then you lose the drop zone, or you use a real LF woofer and you get a poor balance between the drive units, i suggest you try both and find out which one you like best.
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