First Watt for 112 and 109 db speakers

noviygera · 16th October 2011, 05:04 AM

Hi,

I am in the process of moving from a digital crossover to a passive one for my mid and high horns. Even though both speakers are made by one company, Funktion-One, the tweeter horn is 112db/watt (12 ohms)and the mid is 109db efficient(16 ohms). One option is to use one good amp and pad down the tweeter, other option to use separate amplifiers with very similar sound signature for tweeter and mid but with different gain, to eliminate the padding.

I am thinking about giving the First Watt amps a try (currently using Jeff Rowland and Arcam amps). My goal is to preserve the class A sound of Rowland and possibly even improve on it and have consistency in sound.

Any of the two above options seem advantageous? Other good solutions I should consider?

Thanks,
Herman

westend · 16th October 2011, 05:19 AM

Biamping/triamping does it for me so two amps would be a good thing.
An easier path would be to design a crossover network with Lpads or fixed resistors to deal with any level difference.

Nelson Pass · 17th October 2011, 01:56 AM

I would try an F3 with a passive crossover for the mid/top.

noviygera · 17th October 2011, 02:04 AM

Thank you. For the F3 amplifier, would a series crossover with high impedance work better? 28 ohm vs. 7 ohm load if wired in parallel ?

Herman

Nelson Pass · 17th October 2011, 02:08 AM

A parallel crossover will easier to work with, I think. You might just want to
pad the tweeter with a 16 ohm L pad (you can replace it with fixed values
later if you want), and cobble together the appropriate passive. The F3
should be happy 8 to 16 ohms.

noviygera · 06:35 AM

Mr. Pass,

What would be your opinion on J2 vs F3 vs F2 in terms of background noise on very eff high horn with one capacitor as the high pass?

Herman

Zen Mod · 17th October 2011, 07:05 AM

that's easy - just compare their noise figures

pdfs are on FIRST WATT HOME

or like this :

http://www.firstwatt.com/pdf/prod_j2_man.pdf

http://www.firstwatt.com/pdf/prod_f3_man.pdf

http://www.firstwatt.com/pdf/prod_f2_man.pdf

woody · 17th October 2011, 07:30 AM

Using a single capacitor for a compression driver isn't a good idea. Take this example
you have a 8 ohm driver that has a 32 ohm impedience peak at 500hz and you are going to cross it over at 2000 hz with a single capacitor. So by 500hz it should be
down 15db but because of that 32 ohm impedience peak it will only be down about 4db. This was off the top of my head and my math is realy bad but this gives you a
rough idea and your power handeling is also much less with a 6db/oct crossover.

Roscoe Primrose · 17th October 2011, 05:06 PM

If you're using a compression driver in a home environment, and you're pushing it hard enough that you need to worry about power handling, your ears will burn out long before the diaphragm....

Roscoe

noviygera · 17th October 2011, 08:14 PM

>> So by 500hz it should be down 15db but because of that 32 ohm impedience peak it will only be down about 4db.

One of the reasons why I was considering using line level passive filter instead of the speaker level. Will it work with Pass Labs F3 amp - single cap for a first order high pass? How do I calculate the value of the filter cap?

16th October 2011, 05:04 AM	#1
noviygera diyAudio Member Join Date: Mar 2009	First Watt for 112 and 109 db speakers Hi, I am in the process of moving from a digital crossover to a passive one for my mid and high horns. Even though both speakers are made by one company, Funktion-One, the tweeter horn is 112db/watt (12 ohms)and the mid is 109db efficient(16 ohms). One option is to use one good amp and pad down the tweeter, other option to use separate amplifiers with very similar sound signature for tweeter and mid but with different gain, to eliminate the padding. I am thinking about giving the First Watt amps a try (currently using Jeff Rowland and Arcam amps). My goal is to preserve the class A sound of Rowland and possibly even improve on it and have consistency in sound. Any of the two above options seem advantageous? Other good solutions I should consider? Thanks, Herman

17th October 2011, 06:24 AM	#6
noviygera diyAudio Member Join Date: Mar 2009	Mr. Pass, What would be your opinion on J2 vs F3 vs F2 in terms of background noise on very eff high horn with one capacitor as the high pass? Herman Last edited by noviygera; 17th October 2011 at 06:35 AM.

17th October 2011, 07:05 AM	#7
Zen Mod diyAudio Member Join Date: Jan 2003 Location: ancient Batsch , behind Iron Curtain	that's easy - just compare their noise figures pdfs are on FIRST WATT HOME or like this : http://www.firstwatt.com/pdf/prod_j2_man.pdf http://www.firstwatt.com/pdf/prod_f3_man.pdf http://www.firstwatt.com/pdf/prod_f2_man.pdf __________________ my Papa is smarter than your Nelson ! tnx to clean thread ; Cook Book ; PSM LS Cook Book ; Baby Diyaudio FORUM ; BAF Forum & Gallery;I'm dumb

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16th October 2011, 05:19 AM	#2
westend diyAudio Member Join Date: Jul 2005 Location: shorewood	Biamping/triamping does it for me so two amps would be a good thing. An easier path would be to design a crossover network with Lpads or fixed resistors to deal with any level difference.

17th October 2011, 01:56 AM	#3
Nelson Pass The one and only Join Date: Mar 2001	I would try an F3 with a passive crossover for the mid/top.

17th October 2011, 02:04 AM	#4
noviygera diyAudio Member Join Date: Mar 2009	Thank you. For the F3 amplifier, would a series crossover with high impedance work better? 28 ohm vs. 7 ohm load if wired in parallel ? Herman

17th October 2011, 02:08 AM	#5
Nelson Pass The one and only Join Date: Mar 2001	A parallel crossover will easier to work with, I think. You might just want to pad the tweeter with a 16 ohm L pad (you can replace it with fixed values later if you want), and cobble together the appropriate passive. The F3 should be happy 8 to 16 ohms.

17th October 2011, 07:30 AM	#8
woody diyAudio Member Join Date: Jan 2002 Location: Tyrone Ga. U.S.A.	Using a single capacitor for a compression driver isn't a good idea. Take this example you have a 8 ohm driver that has a 32 ohm impedience peak at 500hz and you are going to cross it over at 2000 hz with a single capacitor. So by 500hz it should be down 15db but because of that 32 ohm impedience peak it will only be down about 4db. This was off the top of my head and my math is realy bad but this gives you a rough idea and your power handeling is also much less with a 6db/oct crossover.

17th October 2011, 05:06 PM	#9
Roscoe Primrose Do you smell smoke? diyAudio Member Join Date: Jan 2004 Location: Virginia, USA	If you're using a compression driver in a home environment, and you're pushing it hard enough that you need to worry about power handling, your ears will burn out long before the diaphragm.... Roscoe

17th October 2011, 08:14 PM	#10
noviygera diyAudio Member Join Date: Mar 2009	>> So by 500hz it should be down 15db but because of that 32 ohm impedience peak it will only be down about 4db. One of the reasons why I was considering using line level passive filter instead of the speaker level. Will it work with Pass Labs F3 amp - single cap for a first order high pass? How do I calculate the value of the filter cap?

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