High sensitivity horns versus signal-to-noise

[Blumlein 88]

Well, but in @Amir's case, he does reference it, to 5W (90 dB) and to full power. (104 dB). Those translate to around -84 dB from 1 watt. Using an online converter, that is 0.000004 mW = 0.000 000 004 watts. At 4 ohms, P=V^2/R --> 0.000000004 = V^2/4 --> V^2 =0.000000016 --> V=0.00012649 or 126 mV...did I do that correctly?

Assuming so, back to the original question, if 84 dB down from 110 is 26 dB, how can the hiss from a horn be audible? (Cuz I know sometimes it IS, not even just horns)

I'll remind you, the noise in the source component gets amplified by the gain of the amp. And likely is above your 84 db down from 110 number.

 

[Head_Unit]

I'll remind you, the noise in the source component gets amplified by the gain of the amp. And likely is above your 84 db down from 110 number.

Mmmm...so maybe even if the receiver itself is "OK" the amplified source might still hiss...interesting consideration

 

[Blumlein 88]

Mmmm...so maybe even if the receiver itself is "OK" the amplified source might still hiss...interesting consideration

Hey for an extreme example. In the early days of CD, those players and good amps on my insensitive speakers were dead silent backgrounds. When I switched my preamp over to play a little reel to reel tape, hiss was obvious. You could easily hear it anytime the music was low in level or had subsided.

Now having said that, I don't think you'll get no hiss using horns and an AVR. They just aren't quiet enough.

 

[pjug]

Assuming so, back to the original question, if 84 dB down from 110 is 26 dB, how can the hiss from a horn be audible? (Cuz I know sometimes it IS, not even just horns)

Maybe you won't hear it from your listening position (or maybe you will), but I'd bet you will hear it walking by the speakers. So if you are like me that will gnaw at you.

If you are hoping to use your existing AVR that is one thing, but if you are shopping then why not go with one of the good suggestions already made in this thread, where noise is on the order of 10-20uV (A-weighted). Personally I like the suggestion given in post #3. The horns kind of call for something more out of the ordinary than a solid state amplifier.

 

[RealityCheck18]

Hmmmm,

I'm confused--is your entire speaker 110dB 1w/1m or is just part of it (say the mid-tweeter) 110dB 1w/1m? If it has just part of it, how are you actively running your speaker with multiple channels of the AVR?

I have speakers that use compression drivers at around 108dB but they are padded down to 98dB to match the rest of the speaker drivers--I can hear some hiss when I put my very thick cranium in the horn--there it is! A few feet back all I hear is silence so not an issue for my use.

Either way, just pondering a speaker in your house that can do 110dB 1w/1m across the full range or how you use and AVR for active multi-driver processing. Are you pondering some of those Danley Sound Labs Jericho stadium speakers? If so, that would be something to see and I'm not worthy.

The last option if it is basically a higher frequency horn that is running active--pad it down until the noise does not bother you is an option. True, it wastes power but unless your room is a stadium I think generating a few watts of heat won't hurt to keep the hiss away. Good luck.

 

[MakeMineVinyl]

Because I can, I lowered the gain of my amps and hit them harder on their inputs with higher signal level upstream from quieter components.

 

[Hayabusa]

I was just reading the Denon AVR-X3700H, where Amir purports the signal-to-noise is 90dB at 5W, call it 84 dB re 1 watt. Or 104 dB at full power, which is around the same 84 dB. 110 dB from a horn - 84 dB leaves the noise at 26 dB which should be inaudible.

Playing pink noise at 26 dB(A) in my current living room is definitely audible for me.
The limit for audibility in my current setup (330cm listening distance) is at 15 dB(A)(@ 1meter)

 

[Dave Zan]

...horns-some of which can hit 110 dB/1W/1m. Such horns are known to be sensitive...
And I am really REALLY REALLY sensitive to hiss whether on cassettes or computer fans or whatever, I could not stand it if I could hear hiss out of the speakers

... Or 104 dB at full power, which is around the same 84 dB. 110 dB from a horn - 84 dB leaves the noise at 26 dB which should be inaudible.
Hmmm, really?...

I also have efficient horns and I think you will find this set up not inaudible.

... if 84 dB down from 110 is 26 dB, how can the hiss from a horn be audible? (Cuz I know sometimes it IS, not even just horns)

26 dB means 26 dB above audible threshold so it why should it be inaudible?
If you mean that it should be below room noise level then what you have missed is that room noise is typically quite a different spectrum from amplifier hiss.
So the hiss is not well masked by the room noise.
Also the hiss has a discrete source and sounds are less well masked when in different directions.
I don't know the full details of this but it makes obvious sense as an evolutionary adaptation.
So I would try for a quieter amp.
The Benchmark measures really well if you can afford it.
I am at work on some amps of my own to solve exactly this problem.
They will be quieter than any audio amps of which I am aware, if the simulations are reasonably accurate.
I work slowly so don't wait for me...
But is there any interest in ultra low noise amplifier boards?
They should be <2 nV/rt(Hz) equivalent input noise.
Currently the work is on DIYaudio if anyone wants more details, I will post here on the vendors forum if they work out.

Best wishes
David

 

[Frank Dernie]

I have 109dB/watt horns.
I have driven them using Devialet dual mono amps, a standard type of 40 wpc valve integrated amp, bought because I like the styling and a Job INTegrated.
I haven't noticed any hiss with any of these.
I just checked with the current incumbent, the Job, and at with the volume set at my normal listening level with a CD transport connected to its SPDIF input the hiss is just detectable with my ear in the treble horn bell and there is a barely audible level of noise from the mid range horn, again with my head in the bell.
FWIW

 

[Head_Unit]

Do you think it's wise to use an AVR for powering110dB horns?

Well, any other solutions for multichannel playback appear to be complicated and expensive. Plus since AVRs are sometime criticized for being weak on power, sensitive speakers get around that. It's like poetic justice! Well not really. But something. So I wanted to figure out how to figure out which AVRs would have the lowest noise floors. Here I see SINAD measurements but unless I've totally missed it, not residual noise measurements (???)

 

[Head_Unit]

26 dB means 26 dB above audible threshold so it why should it be inaudible? If you mean that it should be below room noise level then what you have missed is that room noise is typically quite a different spectrum...

OMG, d'oh! And I'm the one who was advancing that same argument to a friend who is fighting aircraft noise-the bend-over-backwards-for-the-planes-screw-the-public FAA pushes for simple standards, purposely ignoring factors like spectrum and also directionality. Actually this makes me wonder if anyone has done masking experiments where the sound sources are in different directions...