so I got my first t30 running..

[Jon Barnhardt]

I need to do some more reading but i'm on the right track now.

See this thread for some voltage indexes: http://billfitzmaurice.info/forum/viewt ... =7&t=16062

Better yet, just use this...

http://www.sengpielaudio.com/calculator-ohm.htm

+1

[osse]

How come no info is included in the plans on how to set the limiter correctly? Or am I missing the point somewhere? I'm sorry for being noob if that's the case..

Only so much can be put into the plans. OTOH there's this:

http://billfitzmaurice.info/forum/viewforum.php?f=14

Could not find too much valuable info about the questions I'm asking.. It's much more build orientated topics there. What I need to know is: should I measure voltage at the lowest frequency set by the hpf for setting limiters? This is where I get highets voltage swing, but people seem to use higher frequencys so I'm a bit confused..

Also:

the driverack PA doesnt have brickwall limiters!

they have a minimum attack time that will allow high transients through.

what does this mean? -
using pink noise and setting the output voltage of the amp to just below clip light comes on, you can turn the pink noise up as far as you want and the limiter will keep it from clipping. BUT. run some music with a beat thru, and turn it up and the limiters will be on, but the beat will still clip your amp.
the limiter takes a small amount of time to clamp down on the signal, allowing transients thru for a short while.

so you cannot rely on the driverack to completely save your drivers if you use a large amp and run it hard into the limiters.

As you recommend the dbx Driverack series in the plan, I guess it's green light, would you care to comment?

Thanks guys for the help!

[Gregory East]

. What I need to know is: should I measure voltage at the lowest frequency set by the hpf for setting limiters? This is where I get highets voltage swing, but people seem to use higher frequencys so I'm a bit confused..

already answered, read again

Also:

the driverack PA doesnt have brickwall limiters!

they have a minimum attack time that will allow high transients through.

what does this mean? -
using pink noise and setting the output voltage of the amp to just below clip light comes on, you can turn the pink noise up as far as you want and the limiter will keep it from clipping. BUT. run some music with a beat thru, and turn it up and the limiters will be on, but the beat will still clip your amp.
the limiter takes a small amount of time to clamp down on the signal, allowing transients thru for a short while.

so you cannot rely on the driverack to completely save your drivers if you use a large amp and run it hard into the limiters.

As you recommend the dbx Driverack series in the plan, I guess it's green light, would you care to comment?

Thanks guys for the help!

If your tunes only tickle the limiter infreqently your largest peaks will not be so much in excess of the limit. If you are in the habit of ignoring advice ( seems likely ) you will be pushing lots of larger musical peaks through the limiter.

There must a be some element of conservatism in the plans voltage limit as there is no history of BFM drivers blowing up on those following the rules with the driverack.

[osse]

. What I need to know is: should I measure voltage at the lowest frequency set by the hpf for setting limiters? This is where I get highets voltage swing, but people seem to use higher frequencys so I'm a bit confused..

already answered, read again

Also:

the driverack PA doesnt have brickwall limiters!

they have a minimum attack time that will allow high transients through.

what does this mean? -
using pink noise and setting the output voltage of the amp to just below clip light comes on, you can turn the pink noise up as far as you want and the limiter will keep it from clipping. BUT. run some music with a beat thru, and turn it up and the limiters will be on, but the beat will still clip your amp.
the limiter takes a small amount of time to clamp down on the signal, allowing transients thru for a short while.

so you cannot rely on the driverack to completely save your drivers if you use a large amp and run it hard into the limiters.

As you recommend the dbx Driverack series in the plan, I guess it's green light, would you care to comment?

Thanks guys for the help!

If your tunes only tickle the limiter infreqently your largest peaks will not be so much in excess of the limit. If you are in the habit of ignoring advice ( seems likely ) you will be pushing lots of larger musical peaks through the limiter.

There must a be some element of conservatism in the plans voltage limit as there is no history of BFM drivers blowing up on those following the rules with the driverack.

Gregory I'm sorry if that seem like case, but it really isn't... I'm very greatful for all you guys helping me out and I'm just trying to get the whole picture, but I guess I'm a bit bold.

Sorry guys

Anyway, I noticed some airleaks, and I'm gonna experiment more with the amp at lower gain settings and get a lower power amp soon!

Thanks!

[osse]

I just got this...thing leak free and running in the corner...

































What the fuck is this monster I've built?

One is... extreme, and she will get 3 sisters..

Guess it will come handy outdoors..

[Bill Fitzmaurice]

Only so much can be put into the plans. OTOH there's this:

http://billfitzmaurice.info/forum/viewforum.php?f=14

Could not find too much valuable info about the questions I'm asking..

I don't think you looked very hard. I mean really, it's on the first page: http://billfitzmaurice.info/forum/viewt ... =14&t=8755

[osse]

Only so much can be put into the plans. OTOH there's this:

http://billfitzmaurice.info/forum/viewforum.php?f=14

Could not find too much valuable info about the questions I'm asking..

I don't think you looked very hard. I mean really, it's on the first page: http://billfitzmaurice.info/forum/viewt ... =14&t=8755

Great thread , but I've seen it before. People seem to use 60 hz sinewave for rms voltage measurement, and this is still something I'm unsure about.

when I'm on 47,4 vRMS at 60 hz, at the same settings it's showing 57-58 vRMS over 41-49 hz. Is this no problem? Or should I limit from the sine wave that yields the highest vRMS output? This might be logical to some... but I don't wanna blow my driver but I at the same time don't want the cab to perform at a lesser level than it could...

[Gregory East]

That is a mystery to me. The only way I can see that happening is if you set the lowpass on the subs too low.

[osse]

That is a mystery to me. The only way I can see that happening is if you set the lowpass on the subs too low.

35.5 Hz. Might be the amp emphasizing?

[Gregory East]

35.5 Hz will be your high pass not your low pass, or else you have royally screwed up setting your crossovers.

[osse]

35.5 Hz will be your high pass not your low pass, or else you have royally screwed up setting your crossovers.

Right ya are, read it wrong.. would be cool with 0.5 hz bandwith before filters kicking in tho..

Lp is set to 106 Hz 12dB BW filter right now, so it won't be the problem

[osse]

Been building 10 hours straight.. second one is taking form! Much smoother this time, great learning curve and the plans are just awesome!!

Love building these badboys.. I guess they wont be very gentle if pushed

[Harley]

... and the plans are just awesome!!...

Get a load of this statement you plonkers who do nothing but moan about the plans!

[Scott Brochu]

plonkers

I had to google this one. Never heard it.
sick.... but funny. You sure you never were a drummer in a past life?

[Harley]

You sure you never were a drummer in a past life?

No. God gave me just one shot at this and so he made me a humble Bass Player

But I live in a country that is always looking from the outside in, PLUS we have a lot of Poms and Aussies living here PLUS we have USA propoganda via Hollywood and so on and so on. That means we get a HUGE variety of funny things to pick from. Take the best and leave the rest...That's why Gregory and I are like we are