Lowest inductance 18's?

[kryptonitewhite 1]

What are some of the 18" drivers with the lowest Le? Does it even matter?

[chris the man 49]

off topic

your builds are awesome, a little crazy but extreely impressive

lookin for info on this as well

[kryptonitewhite 1]

off topic

your builds are awesome, a little crazy but extreely impressive

lookin for info on this as well

Thank you very much Chris, I think I have exhausted the IB3 idea and it was time to move on. I now have Fi reconed Blue Print Audio 1803s in there and I am now moved to go the opposite direction: monster subs. The 35Hz-55Hz range is actually a little painful, and they have trouble getting up high. When i play songs with heavy 55Hz-80Hz content at high volumes they can get a little smelly and theyre not that loud to me. As well, the bottom end isn't where I want it either. I have been trying not to touch the EQ with these subs, but tomorrow I'll be centering at 45Hz and going -9dB with it. Voltage drop is already nasty...I finally found several people willing to build the adaptor brackets to get my 2nd alt mounted, but it will be a while before I can pay for them and a new belt... EQing should only make this a bigger issue

If I could do anything right now, I'd have the 2nd alt added and drop in (4) TC Sounds LMS ULTRA 5400s.

[Aaron Clinton 2,372]

There are two schools of thought on this one. Both sides feel the other is incorrect. To me, it is important, but should not be another one of these singular specs that the uber elite crowd should be clinging onto to tightly.

[Duran 387]

So, you want to look at one specification to choose a woofer? That will yield undesirable results...

[Quentin Jarrell 671]

yes it's important for a true sq woofer wanting to play anything in upper sub frequencies where increased inductance would make the sub sound muddy. However that shouldn't be a concern for someone wanting 4 18's

Edited April 8, 2011 by Audibel Customs

[kryptonitewhite 1]

There are two schools of thought on this one. Both sides feel the other is incorrect. To me, it is important, but should not be another one of these singular specs that the uber elite crowd should be clinging onto to tightly.

I am glad you believe it does matter because that is what I would like to try out for myself

I think all the "elite" uber or not know full well no single spec is ever to be clung to too tightly I have had an Xmax obsession for years and I have recently forced myself to let go

So, you want to look at one specification to choose a woofer? That will yield undesirable results...

who said that

yes it's important for a true sq woofer wanting to play anything in upper sub frequencies where increased inductance would make the sub sound muddy. However that shouldn't be a concern for someone wanting 4 18's

i like my subs to be able to play high when I want them to so it sounds like I am looking for some low inductance is my next experiment if its possible

why wouldnt this be a concern for a person with four 18's? What if I was running 20 10's or only one or two 18's?

[Duran 387]

So, you want to look at one specification to choose a woofer? That will yield undesirable results...

who said that

Erm, I did, you even quoted it.

[kryptonitewhite 1]

Apparently I was lying my ass off! When I first dropped these new bad boys in I brought the EQ back to 0 but left the crossover at 200Hz. Right away it was a problem, so I dropped them to 80Hz and that alowd me to raise the sub level and get LOOOOUUUD.

Well I think they were still breaking in, I couldn't go too long free air in the house because everything was falling and spilling... the TV was hanging by the power cord and boxes of pictures were spilling, it was just a real loud mess that could have started causing damage.

Well today I brought the crossover back up to 200 and I am in HEAVEN! The problem? Current gets DUMPED into these monsters! Now that i am broken in, still my voltage drops... it's like watching the SPL meter...when the subs hit, it goes from 14.8 down to 12V instantly and back up and down with the beat. In these videos this is me taking it easy, only drops from say 14.3 to 13ish?

These subs ROCK, thanks again zora! I just need to get the money together to get the bracket adaptors and belt. These things can get insanely loud when I crank it for a few seconds and watch my voltage drop well below 12V but I know I am just asking for trouble. I'll leave them at 200 where I like them but try my bestest to take it easy until the other alt is added.

[kryptonitewhite 1]

Nirvana - Frances Farmer Will Have Her Revenge on Seattle

Korn Freak On A Leash

Fugees Ohh La La La

[kryptonitewhite 1]

earlier today I think I managed enough voltage drop to clip the amps hard enough to sound like metal.

finally gave in for a while and PEQed for a bit till I got tired of being nervous and put it back. 22Hz Q of 5 I think, +9dB maxed out

For so much airspace and being tuned so low, the bottom notes sure seem to fall off on me. Sure if I was tuned higher, 27Hz-32Hz, it would be MUCH more gain down low, but still... my low notes should be multitudes louder than mid/high, not multitudes quieter even with maxed out EQ.

I suck at this game.

[ssh 924]

earlier today I think I managed enough voltage drop to clip the amps hard enough to sound like metal.

finally gave in for a while and PEQed for a bit till I got tired of being nervous and put it back. 22Hz Q of 5 I think, +9dB maxed out

For so much airspace and being tuned so low, the bottom notes sure seem to fall off on me. Sure if I was tuned higher, 27Hz-32Hz, it would be MUCH more gain down low, but still... my low notes should be multitudes louder than mid/high, not multitudes quieter even with maxed out EQ.

I suck at this game.

Perhaps you should enlarge the enclosure, cut the roof, have some wood panels go up a few feet, should gain some extra cubes.

I don't know, just a thought.

[shizzzon 461]

i seriously think u shouldnt be using an EQ to try and bring out ANY frequency.. especially at 9db if i read that right...

if the install isn't loud at certain notes, it's either tuning error, wrong box size, firing direction or just shitty equipment...

Forcing a boost at any frequency is going to cause a situation where other notes won't be as loud.. it's practically common sense.

So, quit confusing yourself and let your install do the sound for you, dont be god over there without the god knowledge...

Can't change output on everything just by changing settings...

Greatest effect on changing output is install dependent.

that EQ is going to cause you more problems and heating up coils and isn't worth it.

[Impious 1,476]

9db boost = 8x power increase.

[ssh 924]

9db boost = 8x power increase.

No big deal or anything, Lol...

[kryptonitewhite 1]

I shouldnt say 9dB, i should say max 9 clicks. It has 0-9, not dB.

As well, enclosure impedance rise as well as impedance at tuning, which is where my boost is, wouldnt make it actually 3 times the power... since you know, 3dB is a doubling and 3 goes into 9 three times and all.

[kryptonitewhite 1]

Also, I haven't burnt a coil since 2005 or so despite running 6 times the rated power for my woofers. The only time I have made these subs stink at all was while playing music with very high bass at very high levels so EQing the bottom end up would have no effect or would actually help.

And, if a person like me desires a specific range of frequencies to be louder than the rest..since we are all different people with different wants, needs, desires and tastes, just because I boost a range of frequencies to be louder than the rest or as loud to the ear ( 148dB at 25Hz sounds quiet compared to 140dB at 55Hz) doesnt mean I am already running full power and maxing everything out then adding 9dB, 3 times the power, on top of that at that range. I went with four 18's because I tune lower and play lower so i have to move 4 times the air as those that tune an octave above me just to maintain the same SPL, though they sound four times louder at the same SPL an octave higher due to human ear sensitivity and roll off. I play with my subs doing less than a quarter of their potential most of the time, tons of headroom. Until I get to the 20Hz-30Hz range, where you guys unload and think you're "pounding them lows out solidly with authority".

Put your 32Hz tune on a mic capeable of distortion tests and lets see what your SPL is at 25Hz, and how much distortion yours is vs mine. Ill bet my gear on it and take your SAZ and XS Powermaster.

[RAM_Designs 25]

The LMS Ultra is right up there towards the top, so long as we're talking about real subwoofers and not 18" midbasses.

[95Honda 486]

Inductance is important, but not the single spec to take into account in a true subwoofer application.

Additionally, where it comes into play though isn't really the fact that it acts as a low-pass filter, it is the effect that inducance has on changes in current... Put into laymens terms, the more inductance you have the more resistance you have to changes in current (AC current as it relates to us in this aspect) and the slower the driver will resond to changes. This translates into transient performance, or lack there of. In essence, look at inductance as a brake or extra dampening that tries to slow movement.

So try not to think about it as a simple filter, but more of a restriction on transient performance.

But, don't get hung up on this. In the realm of the bottom few octaves, you should be willing to give in to a little inductance in order to have a driver capable of sweeping enough volume to have usable output. When you get a few octaves above the sub realm, this is where the inductance really comes into audible play and the trade-offs in overall design start to favor lower inducance over other parameters such as swept volume...

Hope this helps in some way...

[Impious 1,476]

As well, enclosure impedance rise as well as impedance at tuning, which is where my boost is, wouldnt make it actually 3 times the power

It doesn't matter. Amplifier will output X watts with 0 boost, add 9db boost output will be X * 8. Also, impedance doesn't peak at tuning. It peaks above and below tuning, with the middle point in the valley between the two peaks being the tuning frequency.

Now, let's actually talk about the point you are trying to make. You are incorrectly assuming that because an amplifier is, for example, 1000w @ 1ohm that you have an available 1kw at any impedance. Not correct. Amplifier's clip because it's voltage rails are exceeded, which can happen at any impedance. If the amplifier is 1000w @ 1ohm, then it is capable of 31.62V. The rails are probably a little higher than that, we'll say 35V or so. Now, let's say you boost at an impedance peak where the impedance increases to 20ohm. The amplifier will be capable of 31.62^2/20 = 50w @ 20ohm. But you added 9db of boost. So the amplifier is trying to generate 400w of output. Voltage would increase to sqrt(400*20) = 89.44V. To verify that's a 9db increase, 20*log(89.44V/31.62V) = 9.03db. So, you have rails that are capable of a maximum 35V and you are trying to make the amplifier generate 89.44V....what do you think is going to happen here?

You are also assuming that the amplifier is the only thing that will clip, ignoring the preamp level components.

It might not necessarily damage anything....but I still wouldn't consider it an acceptable practice.

wouldnt make it actually 3 times the power... since you know, 3dB is a doubling and 3 goes into 9 three times and all.

I don't even know what the hell you are talking about right now. I assume you are trying to insinuate that a 9db increase is only a 3x increase in power, which is completely incorrect.

10*log(Power1/Power2) = db increase

10*log(2/1) = 3.01db

10*log(8/1) = 9.03db

Therefore, to get an increase of 9db (i.e. 9db of boost on an EQ) you need an 8 fold increase power.

Another way to think about it.....You need to double power to increase by 3db, then you need to double that power to increase another 3db, then you need to double that power to increase another 3db for a grand total of 9db of gain. So you would have 2 * 2 * 2, or 2³ = 8. So you, again, need to increase power 8x to increase output by 9db.

I understand that the boost may not have been 9db and that you misspoke in the previous post. But your comments that followed that statement made absolutely no sense whatsoever, which is what I was explaining here.

[Aaron Clinton 2,372]

Inductance is important, but not the single spec to take into account in a true subwoofer application.

Additionally, where it comes into play though isn't really the fact that it acts as a low-pass filter, it is the effect that inducance has on changes in current... Put into laymens terms, the more inductance you have the more resistance you have to changes in current (AC current as it relates to us in this aspect) and the slower the driver will resond to changes. This translates into transient performance, or lack there of. In essence, look at inductance as a brake or extra dampening that tries to slow movement.

So try not to think about it as a simple filter, but more of a restriction on transient performance.

But, don't get hung up on this. In the realm of the bottom few octaves, you should be willing to give in to a little inductance in order to have a driver capable of sweeping enough volume to have usable output. When you get a few octaves above the sub realm, this is where the inductance really comes into audible play and the trade-offs in overall design start to favor lower inducance over other parameters such as swept volume...

Hope this helps in some way...

I hope everyone reads this 10 times over, as I am tired of reading about inductance (in terms of a sub woofer) being so incredibly important that with out extremely low inductance it won't sound good or preform cleanly. I know there is so much for me to learn about speaker design, but there are too many people who read a couple of white papers and suddenly they think they know all there is to know about sub woofer design, and that a sub woofer must have some exotic motor topology to have great sound, if not they thumb their noses up.

[kryptonitewhite 1]

The LMS Ultra is right up there towards the top, so long as we're talking about real subwoofers and not 18" midbasses.

Id like to think over time I will be saving up to get some of those midbasses for my wall as of now though I brought my crossover back up and its much better, I just dont have the electical to back them up right now.... at least i found someone to make the brackets for the 2nd alt for a reasonable price, once thats in I should be ok

Inductance is important, but not the single spec to take into account in a true subwoofer application.Additionally, where it comes into play though isn't really the fact that it acts as a low-pass filter, it is the effect that inducance has on changes in current... Put into laymens terms, the more inductance you have the more resistance you have to changes in current (AC current as it relates to us in this aspect) and the slower the driver will resond to changes. This translates into transient performance, or lack there of. In essence, look at inductance as a brake or extra dampening that tries to slow movement.So try not to think about it as a simple filter, but more of a restriction on transient performance.But, don't get hung up on this. In the realm of the bottom few octaves, you should be willing to give in to a little inductance in order to have a driver capable of sweeping enough volume to have usable output. When you get a few octaves above the sub realm, this is where the inductance really comes into audible play and the trade-offs in overall design start to favor lower inducance over other parameters such as swept volume...Hope this helps in some way...

95 thats GREAT info, I think it will help many! Thank you!

...It doesn't matter. Amplifier will output X watts with 0 boost, add 9db boost output will be X * 8.

My bad, I though adding 3dB doubles power, another 3dB doubles again, then 3 more dB doubles again... 3 times the original number.

Also, impedance doesn't peak at tuning. It peaks above and below tuning, with the middle point in the valley between the two peaks being the tuning frequency.

That I did know, impedance saddle, I was hoping to blanket the idea with overall impedance rise, ya caught me. remember youre playing BB with a retarded kid, you gotta let some of my shit slide (OK, no you dont, youre here to correct my mistakes which is what I need, and thank you for that)

Now, let's actually talk about the point you are trying to make. You are incorrectly assuming that because an amplifier is, for example, 1000w @ 1ohm that you have an available 1kw at any impedance. Not correct. Amplifier's clip because it's voltage rails are exceeded, which can happen at any impedance. If the amplifier is 1000w @ 1ohm, then it is capable of 31.62V. The rails are probably a little higher than that, we'll say 35V or so. Now, let's say you boost at an impedance peak where the impedance increases to 20ohm. The amplifier will be capable of 31.62^2/20 = 50w @ 20ohm. But you added 9db of boost. So the amplifier is trying to generate 400w of output. Voltage would increase to sqrt(400*20) = 89.44V. To verify that's a 9db increase, 20*log(89.44V/31.62V) = 9.03db. So, you have rails that are capable of a maximum 35V and you are trying to make the amplifier generate 89.44V....what do you think is going to happen here? You are also assuming that the amplifier is the only thing that will clip, ignoring the preamp level components.It might not necessarily damage anything....but I still wouldn't consider it an acceptable practice.

sigh.... way too much math for me, I get what youre saying. I have it EQed again, it does fine when i am driving, when i am sitting I think i do clip.

I don't even know what the hell you are talking about right now. I assume you are trying to insinuate that a 9db increase is only a 3x increase in power, which is completely incorrect. 10*log(Power1/Power2) = db increase10*log(2/1) = 3.01db10*log(8/1) = 9.03dbTherefore, to get an increase of 9db (i.e. 9db of boost on an EQ) you need an 8 fold increase power.Another way to think about it.....You need to double power to increase by 3db, then you need to double that power to increase another 3db, then you need to double that power to increase another 3db for a grand total of 9db of gain. So you would have 2 * 2 * 2, or 2³ = 8. So you, again, need to increase power 8x to increase output by 9db.I understand that the boost may not have been 9db and that you misspoke in the previous post. But your comments that followed that statement made absolutely no sense whatsoever, which is what I was explaining here.

good to know, and thank you for not jumping me back after I jumped you

I hope everyone reads this 10 times over, as I am tired of reading about inductance (in terms of a sub woofer) being so incredibly important that with out extremely low inductance it won't sound good or preform cleanly. I know there is so much for me to learn about speaker design, but there are too many people who read a couple of white papers and suddenly they think they know all there is to know about sub woofer design, and that a sub woofer must have some exotic motor topology to have great sound, if not they thumb their noses up.

I hope me getting mouthy, therefore warranting these very insiteful posts, helps everyone!

Again, thank you all for your great input!

[Oscar 2]

I know its an old post, but with regards to low inductance 18s, it doesn't get much better than Aura's NRT subwoofers:

The 15"s were used in Magico's Ultimate II home speakers that sold for several hundred thousand dollars:

[Infinite913 381]

No intentions of thread jacking but I could of swarn you made a bet against me for your alternator and I did a 156.7 at 27hz

[kryptonitewhite 1]

No intentions of thread jacking but I could of swarn you made a bet against me for your alternator and I did a 156.7 at 27hz

I said at 25Hz