Sensitivity

[DJ Big Ronn]

I'm not sure if this would be of any use to anyone, but i'm gonna throw it out there anyway. I always knew that BFM cabs were way more efficient than store bought speakers, but that never gave me any real world info. Last week I was the Dj for four high school project graduation events. Starts at 10pm, ends at 6am mon. thru thurs. In the main room, i put up 4-Dr250's and two T-48's. The problem was that last year, no one could hear announcements in the other room. So this year i got some 100ft cables and ran two more T-48's and my backup Peavey's.
With all tops on one amp, the sound in the main room was LOUD. Sound in the second room almost inaudible. About the only thing that you could hear was the CD horn, not enough power to even get the mids going. I guess I'll need to build two more DR-250's for next year .
Like i said, i dont know if this is useful to anyone, but I thought it was a lil real world info for anyone that was wondering just how efficient the BFM cabs are.

[Tom Smit]

Would there be any difference if the amp was in the same room as the Peaveys, and running the 100 foot cables to the DRs? IOW, backwards from what you had. I'm asking because methinks there is some power loss through the cables.

[Sydney]

there is some power loss through the cables.

That can be determined.
Voltage drop is the amount of voltage loss over the length of a piece of wire. Voltage drop changes as a function of the resistance of the wire and should be less than 2% if possible.

Syd

[Turntablist]

there is some power loss through the cables.

That can be determined.
Voltage drop is the amount of voltage loss over the length of a piece of wire. Voltage drop changes as a function of the resistance of the wire and should be less than 2% if possible.

Syd

Also, it is the high end that is rolled of first if there is any loss in the cables and the highs were there according to Big Ronn but not the mids.
I'd say Big Ronn's conclusions are accurate.

[Sydney]

Also, it is the high end that is rolled of first if there is any loss in the cables and the highs

That is indicative of added inductance not merely adding resistance; which will create a voltage drop, and reduce gain universally.
Resistance and inductance and capacitance are separate issues.

Note: This was a response to Tom's inquiry about determining power loss in the cable specifically. It was not an attempt to explain what Ronn had posted

Syd

[DJ Big Ronn]

Yeah, i thought of that, and im sure there was some measure of power loss. The dr's were on 50ft and the Peaveys 100ft. I had noticed the volume loss long ago when I only had 2 DR's and ran the Peaveys along side them. The diff. was more noticable however because the spks were in different rooms this time. I unplugged the DR's momentarily and was able to get the Peaveys to extreme levels, but with MUCH more power. I posted this in case anyone that was on the fence about building, it may sway them towards DR's. This is the kind of stuff that i wanted to know when i was deciding.
On a second note, the T-48'ws were on 100ft cables also and far outran the Peavey tops.

[Tom Smit]

Thanks for clearing that up DJ Big Ronn.

[SoundInMotionDJ]

Voltage drop changes as a function of the resistance of the wire and should be less than 2% if possible.

The rule of thumb that I have used is to keep the wire impedance (or resistance) to less than 5% of the cabinet loads. But 2% is still less than 5%.

[Gregory East]

Someone should do a balance test from a distance between a DR and a home stereo speaker, and different makes of PA speakers and post it on youtube, they are probably more sensitive than all but the EAW KF touring component range.

What's sensitivity of a KF top, and driver count, box size?

I reckon most would think a vid was rigged before believing their favourite speaker could be monstered by a DIY job. I substituted a little bookshelf speaker for a DR250 once. Thinking the wiring was mucked up it was so nearly inaudible with BAT still going.

[Bill Fitzmaurice]

Someone should do a balance test from a distance between a DR and a home stereo speaker, and different makes of PA speakers and post it on youtube, they are probably more sensitive than all but the EAW KF touring component range.

Good idea, why don't you go out and buy a dozen or so cabs and do it? When you do you'll find that DRs are more sensitive than EAW KFs.

[Harley]

As for DJ Big Ronn, why not put two DR250s in one room and two in the other room?

Good grief, his post is over two years old...move on will you

[Bill Fitzmaurice]

As for DJ Big Ronn, why not put two DR250s in one room and two in the other room?

Good grief, his post is over two years old...move on will you

He resurrected this one from five years ago:
http://billfitzmaurice.info/forum/viewt ... =13&t=4205

[Bruce Weldy]

As for DJ Big Ronn, why not put two DR250s in one room and two in the other room?

Good grief, his post is over two years old...move on will you

He resurrected this one from five years ago:
http://billfitzmaurice.info/forum/viewt ... =13&t=4205

There really should be a prize for raising the dead.....you know, kinda' like whoever drove the farthest to get to the reunion.

Maybe the appropriate prize would be a calendar?

[AntonZ]

I'd say cut the man a little slack. We've all been new to forums once. As well as young and enthusiast at some point.

[Bruce Weldy]

I'd say cut the man a little slack. We've all been new to forums once. As well as young and enthusiast at some point.

Yeah, you're probably right.....but there have been so many dead posts popping up that I thought I was in a Zombie movie.