What is Your Signal to Room Noise?

[PeterSt]

1 hour ago, Sonicularity said:

Live levels from which perspective?  The piano player?  The listener?

 

The piano player. At least that is what I'd like to do but this is too loud. A piano (open wing - just measured at 1m) is 90dBSPL. This is doable as a piano does not come across as too loud in a random home's room. But now put a trumpet player next to it.

No.

A drumkit is 110dBSL on the splash cymbals when used in rock fashion.

No.

 

My average listening level is ~85dBSPL (these are the regular peaks). When I'm in the mood or the music is - 90dBSPL. Maybe a tad more some times.

This with the notice that this goes on each evening for ~3 hours in a row, the family just in the room. The family being able to be there is almost an explicit measure because this can only be so (the year through) when SQ is unsurpassed and zero tiring. The surprise could be that the highs are so loud that these (like from a cymbal) imply sheer (measurable) sound pressure already. Like with the real drum kit. Try this at home, see what the needle in your SPL meter does (probably nothing much) and try to envision it moves on the highs foremost and that that does not hurt ...

My "luck" is that the highs/cymbals are still not rendered like reality because music playback would become impossible, I'd say.

 

Summarized, playing at real levels is impossible (like it could be done tuned on a piano) because other instruments become too loud in the (too small) room (which is even quite large is my case).

 

Ambient noise from computers and such is not present these days. Living in a rural area (actually "nature" as such - in the middle of a lake) implies a lot of outside noises from (water) birds. But this just belongs.

I once measured the ambient noise when all was quiet and still was 4dB or so higher as that can be in real desolated area. I forgot the absolute reading. Somewhere at the end of 30's, I'd say.

 

PS: I use the SPL meter about daily. For me it is a constant check whether what I/we can bear without the slightest pain, is indeed as loud as it feels (the sound pressure). This can also go the other way around, like "ouch - but this is only 80dBSPL ? ... something devastating wrong).

[PeterSt]

8 hours ago, Sonicularity said:

When I cranked up the volume level to where I felt was jamming to my ears, and not a level I would keep for more than a song or even part of a song, I only read 70.6 dBA on the meter.

 

This is actually what made me respond the way I did (which was not in a bragging fashion at all). This seems so far from reality that I can't comprehend.

Of course - I can envision people listen to music like this on Sunday mornings in a nice sunny corner of a room with a newspaper, some very faint background little music. But to say that if it would be louder than 70dB (which would be dish washer level) it would be jamming to the ears ... ?

Maybe your SPL meter is kaput ? or mine. Haha.

 

Now I'm not really sure what the message is or should be. I suppose the subject is something like: the lower the ambient noise level, the lower the music volume can be, because all is relative to the base noise and we must (try to) be well above that. This is also what I see a bit in esldude's/Dennis his post. But will it really work like that ? Thus, supposed my ambient noise would be a constant 50dBSPL for some reason, could I suddenly bear 100dBSPL easily ? seems hard to imagine. Still, all would be related to our - or the dynamic range we perceive. This makes it an interesting subject.

 

For me too the dynamic range "we" can perceive is something like 70dB maximum. This does not mean that we can utilize it, never mind we can also hear into the noise. Thus, it is hard for me to imagine that we can utilize that 70dB of range when music plays at 70dBSPL and we would be able to hear right into the noise up to 0dBSPL. Or ?

The other way around ... if my ambient noise would be 38dBSPL, would I be able to bear 108 dBSPL ? well, "bear" maybe yes, but would it be required to perceive everything which is in there ?

Or would 90dBSPL be OK because I can hear 18dB into my 38dB ambient noise ?

 

Yes, interesting.

 

I guess this is besides the hobby in a hobby of some (like me) who are only satisfied with something like concert levels. I mean, if I listen to Smoke on The Water from Made in Japan, I want to see that stage from the cover. This does not work on dish washer levels. At least not for me. Never mind I could hear all what's in there (say the full 70dB of dynamic range).

[PeterSt]

2 hours ago, esldude said:

Play a quiet 3 khz tone and see where it disappears.  It won't have to be 40 db SPL for you to clearly hear it.  

 

That is entirely true of course. I didn't even think of that.

[PeterSt]

Here's a little anecdotal story which is not 100% related, but still to some large degree it is:

 

So we build these speakers. Complete systems actually and some times people buy it all together.  

The speakers are 118dB sensitive for the top horn and something like 109-110dB for the woofer section. This sensitivity is crazy of course and has its downsides as well;

We propose a system without preamp and with digital attenuation only by means of in-PC software. This means the amplification is always at full gain. Say that the RMS power is 30W with the notice that this counts for each of the individual drivers in there, but for the woofers it is a little more than 50W.

This would be close to fighter engine level, or turbine dry cleaner Nascar track vehicles, if you want.

 

This also means that even the slightest system noise would be blasted through closed doors of the listening room. This means that no noise at all is allowed to be there. In practice I know that the noise level (full gain) is only allowed to be -120dB maximum or otherwise you would hear it (say when music is not playing). And so -120dB it is.

 

While I was just talking about electrical noise, there is also acoustical nose. Think transformer hum with the notice that even capacitors make noise.

 

So while we build the speaker over here and have good knowledge about the other elements of the complete system, we obviously check for audible noise which is thus on the limit of difficulty to begin with. Then we ship the lot (envision three pallets).

 

At the customer all is build up, and there is a hum audible. Customer complains. During music playback it is fine, but the system is and should be on 24/7 and the hum is a pain when you hear it all the time. Obviously.

From our manufacturer's point of view we can not understand. With the experience we have on ground loops and what not, all is analyzed. Took weeks if not months in this occasion.

We decide to measure with an SPL meter because the ears of the customer are suspect. Could he be hearing better than we over here ? we even pulled people from the street to test our system over here (which system measures the exact same as the one for this customer). We indeed found that what one person would hear an other would not really. In the end a logical matter. But this was all with ear-in-speaker and nothing about several feet from it and anything audible for anyone.

 

In the end I bought an SPL meter. I calibrated it for some mutual reference, measured, registered all and sent it to the customer with the task of the same measurements. And then the surprise ...

 

Feel it coming ?

 

Over there the ambient noise was 4dB less than over here. This is how my mentioned 4dB came about in my first post.

So because the ambient noise was 4dB less there, the hum which surely was there, deep down, became audible (became profound) . The hum was now measurable just because the base level was 4dB less. I couldn't believe it.

 

I guess it is very similar to it being dark at night vs it being super dark. Over here I don't think there is a single spot in the whole country where it is super dark. A city at 15 miles will lit the sky and stars or satellites will be (way) less visible because of it. And cities are everywhere. Similarly those cities must make noise. So even at night when everybody is supposed to sleep, there must be environmental noise. This customer, in the middle of nowhere indeed, in India, just lives in a way more quiet environment. Probably more dark at night as well.

 

And now I can so much imagine how this 4dB of less ambient noise can imply a much better music experience. Undoubtedly one must be able to hear more into the music, just because there *is* more. And as we know, cranking up the volume isn't really the solution (like 40dB + 70dB is seriously too much).

[PeterSt]

2 hours ago, STC said:

Could there be other factors that you might have had overlooked?

 

I don't think so. But you seem to make a few stacked mistakes. 

 

First off at my place it is 39dB (( can look it up if needed). This is just audible as distinct sound *if* there were to be a sound. But think like a computer fan. IIRC they start to be audible at 28-29BSPL (this is a bit of a long shot because they are measured differently for their audibility level). Anyway, 39dB and not 30dB.

 

Next is that the noise floor over there is 4dB lower and thus is at 35dBSPL (you are already at 26 there). Thus now it needs a hum with the relative level of 4dB to make it clearly jump out of 35dB. Of course it does not really work like this because the noise won't be on top of the environmental noise. It is just a hum and btw in this case mechanical (transformer) hum. On a side note, one of the tricks to capture it the most easily is to let make the SPL meter (or microphone for that matter) contact with the speaker surface (and that in a special angle which allows for "bounding" on the surface (so we'd measure a derivate of the the real noise which still is acoustical)). Anyway ...

 

What I considered mentioning in my first post, is that the SPL I measure in my room and from this speaker does not decay (decrease) with 6dB per meter of extra distance. Also not 3. Instead it is almost nothing; it is between 4 and 5dB at 8 meters distance (7 meters more than the standard 1 meter measure). These are horns ... Thus, there is a very high degree of beaming and therefore not the normal decay of a 180 degree spreading speaker. Add to this that there is extra reflections on the side walls, because again there's beaming on to them (towards the listener).

Beyond mentioned 7 meters there is no decrease because the back wall starts to weigh in with reflections.

 

Maybe it is unimportant, but  let me add that any acoustical noise like the transformer hum, is amplified by the horn (woofer section in this case). Thus there's just as well "efficiency" in that, sadly. Plus it is as directional (bass really is that too).

[PeterSt]

6 hours ago, bluesman said:

1. The fact that there's no input attenuation on the power amp does not mean that it's "always" dissipating 50W at the speakers.  It will do so if (and only if) its input signal reaches the voltage at which it achieves its rated output.

 

Hi - I don't think anything was saying that. However, the 50W (30W) implies a gain. And the gain is 20 (I can tell you). Now "mV" of noise as such, will surely blast through closed doors if only the efficiency is good enough.

Try to set your volume wide open, and now listen to your speaker (tweeter). Hear something (more or less faint) ? good. Hear nothing then no dice today. But if you do, next up is the efficiency. Is it 94 ? (very good already) then add 24dB to reach what we have here. And I tell you: if you hear the faintest of noise already, increase that with 24dB will imply fairly blasting noise.

And this was for 94dB of efficiency. This can be way less just the same ...

 

Thanks for that chart; nice.

 

6 hours ago, bluesman said:

noise at 40 db will only be clearly and directly audible if and when the SPL of the program is below 50 dB.

 

Although it will be off topic, these matters are not really about "clearly and directly" (however, you may be right on it) because it is about distortion. Thus no matter you won't be able to hear it "directly", it easily shows on an analyser  (even a scope when the differences are low enough) and therefore are always important. But anyway, this is a different subject. How the ambient noise floor would be able to make the background more black and such, is on topic and this we could wonder. Mighty difficult to check / compare.

[PeterSt]

7 hours ago, STC said:

You have 6dB loss for every doubling of the distance. Not every 1 meter.

 

Oops, I surely wrote that wrongly. Thanks for the correction. But point is, it is not about that (hence the easy mistake - blurp). It is about the directivity and how that makes the rule fail. Try a tube ... (of 100m long if you want).

[PeterSt]

17 minutes ago, STC said:

So at 7 meter and a 4dB lower NF

 

Nobody said that was at 7m at the customer.

 

18 minutes ago, STC said:

I have nothing further to add. 

 

Then try that tube. Don't you believe that or what ?

 

[PeterSt]

5 hours ago, bluesman said:

You're doing it again.  SPLs in dB are not additive. What you describe simply does not happen - adding 24 dB of noise to a 94 dB signal will result in an SPL of exactly 94 dB.

 

You know what ? I understand what you are talking about but I have no clue of the why of it. You seem to be thinking (if I get that right) that I say or claim that noise "blasts" on top of music. I say nothing of the kind. Let's agree that you don't have the slightest idea of what *I* am talking about. And if we don't agree, that's what I'm thinking anyway.

 

There is no signal. Did you get at least that ?

[PeterSt]

6 hours ago, bluesman said:

 

So what are you trying to do in the quoted sentence if you're not trying to add 24 dB to 94 dB?

 

I don't know. I am not aware of it despite what you quoted from my text. I'm afraid you missed the crux of this thread ?

 

Otherwise I live in an other universe. Shall we keep it at that ?

Again, I will state that there's nothing wrong with what you say, hence we agree. So you must be reading different things in my posts. Like adding dB's (looks to be your hobby horse).

 

Stop this loop.

[PeterSt]

4 minutes ago, AudioDoctor said:

This is at roughly the listening point

 

Hi - Although it would inherently compare all of our figures, this is not how SPL is measured. This is at 1 meter distance from the speaker (some make that 2, but that is an other standard). So if I say I play at 85dBSPL, this was measured at this 1 meter distance. I know ... this makes it incomparable for room sizes and such.

Now what ...

[PeterSt]

Do you ?

[PeterSt]

As I suggested, it would inherently compare our figures (if it were about that in the first place). But it is just not how it is done. Nobody would expect it either. At least not me ...

[PeterSt]

Just now, AudioDoctor said:

Roughly, yes...  ha. I listen at my computer.

 

Oops.

haha

[PeterSt]

1 minute ago, AudioDoctor said:

You're free to ignore it if you like.

 

No ... It is just that I now think why we never talk in terms of "at the listening position". Thus, exchanging figures from that @1m rating actually don't compare (obviously). Still "we" always do it like that, and then somehow translate it to room size or forget thinking about it in the first place.

I think I mentioned that my 85dBSPL decreased to 81dBSPL at the listening position but there was an other reason to mention it.

 

There is a somewhat larger thread from [forgot the handle - cucumber something] about SPL from the orchestra hall and the listening room. Somehow we always keep talking about the 1m distance, or at least I do. It just is "in the system"; I think in the thread we're in currently, this started about real levels. So, you go to a piano, measure that at ~1m distance, go to the listening room and tune at at 1m from the speaker. Not the listening position. Again, obviously. But ...

[PeterSt]

2 minutes ago, AudioDoctor said:

I was just having fun with my new app and kept measuring things, because why not!

 

I use it all the time. It gives you insight in exactly what you were saying 10 minutes ago; you learn what you perceive as loud but which may not be loud at all, and the other way around. In the end that in itself is a measure of how "good" the system is or behaves. Anything which comes across screaming(ly loud) but is not (which requires the measurement), isn't the best for quality as such.

[PeterSt]

3 minutes ago, AudioDoctor said:

It would really be something if we all used the same album as well.

 

And of course that is also an important dimension. This is how I always speak in terms of peaks only. With that I assume that we set the volume to what we think we can bear for the moment (mood and such), which of course for rock is far more easy than for classical. And do that C weighed or else the peaks are quire meaningless.

So indeed, there is more to it than just aim an SPL meter. Funny ...