O10.5 holy crap on no watts!

[phil]

I just wanted to state how amazed I am about how much noise my new o10.5's with melded arrays put out. I haven't gotten a amp yet and have just used a 10y/o $80 surround sound amp that only puts out 45w, and in the house it's loud enough to be unbearable!

The best thing that really blows me away is how you barely loose any clarity or loudness moving away either direction of the cab, almost it seems up 90 degrees away from the front! I have never experienced this before and I've been in front of quite a few sound systems in my 15 years of avid music enjoying.

This was my 1st time ever using a table saw, a router or done anything with wood besides cut the end off a 2x4 with a circular saw. I'm not sure of the time as we had a new baby about a week into figuring all the tools out, but once I got my panel jig square and had everything figured out and started over from the beginning (for the 3rd time), it took about 1 day to cut most of the wood. I think now that I could probably build a pair in about 20 hours shop time.

They ended up not coming out to specs do to not having a printer and reading through multiple designs and trying to write what I needed down to take out to the shop with me, etc..., but they still sound great.

I wasn't confident with my plotting skills at the beginning as I've never even done basic measuring before, or used a square before, so didn't trust myself to draw everything on the top and bottom 1st which forced me to kinda wing everything else. TRUST YOURSELF AND FOLLOW THE DIRECTIONS IF YOU'RE NEW TO ALL OF THIS.

Once I did everything it wasn't as hard as my brain made it out to be.

One of my major mistakes was that I glued together 10 piezos before I remembered (lack of printer) I needed the top and bottom only cut on one side, so I just made the boxes with 14 instead of 12, as I didn't have enough to completely redo what I had already glued together.

Another major one was because I was having to wing everything measurement wise and all my dimensions were off, and I was having to hand measure everything out, after not drawing it all out 1st, I cut my horns similar to the 0t's and went ahead and installed them like that.

Regardless, they sound great and put out a blistering amount of noise w/even 45 watts. I can't imagine what they will sound like under full power.

I can't wait to get the mains and subs done and get it all put together and hear it in a proper (large/loud) environment. Especially since I have a printer now .

[Strapping Young Stu]

Regardless, they sound great and put out a blistering amount of noise w/even 45 watts. I can't imagine what they will sound like under full power.

Not more than about 6dB louder!

Stu

[Ron K]

Regardless, they sound great and put out a blistering amount of noise w/even 45 watts. I can't imagine what they will sound like under full power.

Not more than about 6dB louder!

Stu

[phil]

Regardless, they sound great and put out a blistering amount of noise w/even 45 watts. I can't imagine what they will sound like under full power.

Not more than about 6dB louder!

Stu

lol, that's not much.

[SoundInMotionDJ]

There is +20dB over the sensitivity limit in the first 100w of power. It would be really rare to get more than another +6dB from any speaker...power compression being the @#$%! that it is.

--Stan Graves

[phil]

There is +20dB over the sensitivity limit in the first 100w of power. It would be really rare to get more than another +6dB from any speaker...power compression being the @#$%! that it is.

--Stan Graves

At that point did I read somewhere correctly that another 6db is almost double in loudness?

[Sydney]

A 10db increase in SPL is generally perceived as a twice as loud.
http://hyperphysics.phy-astr.gsu.edu/Hb ... /loud.html

[phil]

A 10db increase in SPL is generally perceived as a twice as loud.
http://hyperphysics.phy-astr.gsu.edu/Hb ... /loud.html

Wow, thank you for that link!!!!!!!!!!!!

That makes total sense, and explains a whole lot in a few sentences that I've been needing to understand and haven't found where to grasp the information from, mostly out of just not knowing what to look for if that makes any sense.

[Sydney]

haven't found where to grasp the information from, mostly out of just not knowing what to look for if that makes any sense.

Yes it does ...
The HyperPhysics and lot of related stuff is here
http://www.billfitzmaurice.net/phpBB3/v ... =18&t=5059

[AntonZ]

And then on bass forums there's plenty of bass players saying like 200W is far from enough for gigging, you need at least 300-400 for that and many have 1000W or more. It all doesn't go that much louder than my nearly 20 year old 200W Trace head

[bgavin]

My Peavey Minx 110 will drive a T48/OT212 quite nicely...

[phil]

And then on bass forums there's plenty of bass players saying like 200W is far from enough for gigging, you need at least 300-400 for that and many have 1000W or more. It all doesn't go that much louder than my nearly 20 year old 200W Trace head

So you guys are saying drivers see the majority of their spl in the 1st 100 watts?

So if a cabinet isn't efficient, to get more out of it, you would need a whole lot to get a little extra?

[jcmbowman]

So you guys are saying drivers see the majority of their spl in the 1st 100 watts?

So if a cabinet isn't efficient, to get more out of it, you would need a whole lot to get a little extra?

You gain 10dB for 10x the power.

1 watt -> 10 watts = +10dB
10 watts -> 100 watts = +10dB
to gain another 10dB you'd have to go to 1000 watts, but pretty much every driver out there today starts to run into power compression at or below 400 watts, so at best you'll gain 26dB on top of the measured sensitivity @ 1 watt. That's why having efficient cabinets is so crucial. The only other way to get more output is to add more cabinets, and that has its own problems.

[bgavin]

So you guys are saying drivers see the majority of their spl in the 1st 100 watts?

Absolutely.

Take my silly little 35w Minx as an example.
Its 16 volt output produces 125 SPL in a T48 at 100 Hz.

To get a +6dB increase, the amp would have to jump to 35v, or 140 watts.
Or, you could add a 2nd T48 for the +6dB and keep using the Minx.

Jumping up another +6dB from 140w is 558 watts. And so forth.
None of the drivers we use will accept 558 watts without power compression, so you have to add more speakers.

In the end, it is not about the gross power.
It is all about the individual sensitivity, then adding more of those boxes until satisfied.

[Sydney]

In the end, it is not about the gross power. It is all about the individual sensitivity,

The significance of the sensitivity is shown when you graph db vs power.
And because we perceive sound logarithmically not linearly with power
A typical speaker producing 90db for 1 watt requires 10 watts to get it to sound twice as loud , the next 10 db require 100 watts, and the next doubling of apparent loudness would require 1000 watts, BUT would be unobtainable because voice coil thermal effects have already started and the voice coil would fail.
A horn speaker with a sensitivity of 100db/1wt/1M already sounds 2x as loud as a 90db speaker for the same wattage ( ie add the 1 watt/SPL value to the graph value ). At 10watts it is 110db, at 100 watts - 120db (theoretically). On the average the horn will only require a fraction of a watt to be very loud.

High Sensitivity starts you off ahead of the game.
BTW: It is not uncommon to have peaks that are much higher; A 90db speaker with 1 watt has been observed requiring 200 watts for brief peaks.
With a high sensitivity speaker you have plenty of headroom for these peaks.
It is the reason that guys with very small SET and Class A amps ( that only put out a few watts ) are satisfied when hooked up to full range horns.
Also something to consider next time a discussion takes place over the (in)significance of Max power handling; Very little is gained ( except damage ) after the 1st 100 watts (20db).