Gain structure and system balance

Dra

I have a question. Assuming that gain structure is set using divided pink noise output bands.... Do I make a x-over gain adjustment?

Top cab at rated output = 128 db (x2 cabs = 131 db) (x4 cabs = 134 db)
Sub cab at rated power = 134 db (x2 cabs = 137 db) (close coupled subs = 140 db) Is this right?

If I have a 128 db capability for tops and 134 capability for subs (6 db difference), do I reduce the x-over sub output gain -6 db?

DRA

wolfie

Dra -

Not sure I understand the question, but it will be interesting to see what Gadget has to say.

W

Gadget

Dude.. I've got my mind on other things right now.. I am kinda scratching my head here a bit too.. 137 db that's HUGELY loud! I usually run about 105-110db.. As we have posted the idea of gain structure is simply to get the system all talking the same language, then we set the balance by ear, If we let the gain structure set the volume of the components the biggest amps on the most efficient speakers would kill all the rest.. thus my confusion...I'll be scarce for a bit..

G

Fanman20

Hi Dra

Can you every have too much sub????

What is going though the subs? Band CD Disco vocal

Top cab at rated output = 128 db (x2 cabs = 131 db) (x4 cabs = 134 db)

Where did you get these figures??

What are the top boxes and subs that can produce 140 db


Glad I am not your neigbour


Mark

Dra

:oops: Sorry. I am using the sensitivity spec (1w @ 1m) and then adding 3 db per doublng of power until reaching the limit of the amp. So, those max spl's are 1 meter from the speaker.

The 140 db sub ... 134 db is max output out a single sub (@1m) add a sub and gain 3 db (137)(right?, from doubling). Here's where my question is fuzzy... close couple those 2 subs and gain ANOTHER 3 db (140)?

My premise question is since the subs (on paper) outrun the tops by 6 db, in order to achieve flatness in the system I should reduce the input to the sub cab by 6 db. Correct? Because as we all know in theory this is a thing as too much sub, though ususlly never achieved.

DRA

Gadget

Having some coffee and then going to pick up the \"little lady\"...If your asking a question about DB and coupling.. then we need to discuss free space, half space.. etc, Usually free space spl's are going to be MUCH lower than 1/2 space, which would be against a wall.. corners even more gain... Speaker MFG's use subterfuge and misleading information (called creative advertising ) to sell product...They have NO standards to meet, and really aren't held to truth in advertising. When we (the professional audio community) see specs like that we just chuckle...That is probably a burst (millisecond) tone at a peak( the most efficient point) frequency of the driver and horn... it's an old trick, and...then they take a group efficiency to add to that... even the big boys like Meter and EAW give you a spec that CAN be reached under nearly impossible conditions.. it's a bad deal, but there are real world companies that DO tell the truth, that measure @ 10 meters @ 100watts instead of 1 meter at 1 watt which is a useless figure because as I said the figures can be manipulated..Danley sound is the manufacturer by the way, he developed the LABsubs for the DIY market... I would think the speakers can probably do 125- 127 by themselves, but again, we need to specify a frequencies they produce.. and some will be WAYYYY less.. and as you go up or down the numbers will go down drastically...Figures for average SPL of the full frequency range to 3db down would probably be more in the 115-125 db category if that...you do get a coupling benefit, but it's not infinite...I think Danley stated the THEORETICAL limit (semantics) is in the 170-175 db range, and that is for infinite number of cabs....
g