Axiom Home Page Forums General Discussion Technical Questions Separates and a sub

I currently have the MT80's VP150 and 4 QS8s' running on a Denon 3803.
110 watts per channel into 8ohm I think it is rated 160 into 4ohm.
Now I have no sub currently although and HSU VF3MKII is landing in my room end of June. ( on layaway now ).
Here is the situation ... then denon volumn goes from -70 db to +15 db. I have to turn it to about -20db when watching a movie ( -15 to -10 db if I am alone watching a movie ) this is my comfort zone, but the girlfriend complains of the loudness.

No way I understand this is my denon is pumping out wattage to produce the bottom end that the MT80's are drawing to produce the low end. I guess this is why I have to turn it up in order to get louder, problem is I have no head room left, if it is needed as the 80's are going to draw current from the amp.

when the HSU arrives will this all change .... since I now have a sub , cutoff will be 80hz setup in the amp as LFE + Mains most likely .. .so know my amp will not be using any current for the bottom end as the sub will be producing the lows and has it's own amp. So, really this should free up a major amount of wattage in my amp ... right ?
I should only have to crank it up to -30db and have 50% headroom left no right.

I am going seperates soon and want the Emotiva or Outlaws mono blocks but, being only sold in US makes it hard on the pocket book, unless the dollar rises higher, which I am hereing very close to even within the year.
No with these if I run 7 channel each speaker has it's own 340 watts module to drain if needed...it's own transformer capacitors etc, and the sub has it's own so it should go defeaning loud right.

I had to read your post a couple times to understand the question -- sometimes the fingers work faster than the brain when you're anxious -- but I think I have the gist of it.

When you get your sub and tell your Denon to cross over at 80 Hz and setting your mains as small, it is true that your receiver won't have to work quite as hard to drive the M80s since it will be relieved of the power-hungry sub 80-Hz duty. This shouldn't have too large an effect on what volume level you have to set your Denon to in order to achieve your desired listening level, however.

Your understanding of power and resulting decibel level is flawed. Keep in mind this rule of thumb: every 3dB increase in sound level requires 2x as much power. So, assuming the dB levels of your volume control are accurate (e.g. every 1dB increment on the display corresponds to a 1dB increment in your room -- and this is hardly ever the case), every 3 clicks of the knob will double the power used. Essentially, this means, in theory, that you still have 50% headroom left at 3 clicks below max.

oh, see I thought if I was up to turn the dial to about 75% it would be bad.

I have no clue what the dB settings on my Denon mean. If anyone has a good explanation, I'd love to hear it.

To get to Troy's issue, at sub-woofer frequencies (30Hz and below), the M80 requires about 1W to produce 66dB at 3 feet (at least in my room it does). So for the pair, you can get 69dB at 3 feet per watt. If you're sitting 8 feet away, you may still be getting around 69dB if your room is quite live. 69dB isn't very entertaining so you probably have it turned up to say 84dB so now you are consuming 32W for those lows. Once you add a sub, your amp will be relieved of these 32W.

More importantly, you have the main volume turned up so high in order to hear the lows that you are torturing you and your loved ones with the mids and highs. Since the 80s are more efficient with mids and highs, you are probably pushing more than 105dBs in those ranges and I am sure you are taxing your amp during dynamic passages.

So when you add the sub, you will have more sane listening levels and it may even sound cleaner too.

The sub will free up a LOT of amp capacity at higher levels, but i doubt it will become a louder system if calibrated right. If anything it might sound less loud as the newfound headroom will eliminate some clipping at high levels. It will sound better at the higher spls though.

Good description Murph.

I want to add that the 85 dB THX reference is for average sounds. Peaks are considerably higher. At this calibrated volume, the peak for each channel is 20 dB higher, or 105 dbfs. The LFE channel can peak to 115 dB.

At reference volume (-0 dB on your calibrated receiver), there is potential of hearing these channel peaks combine to over 118 dB. Listening at -10 below reference for example cuts these numbers by 10 dB.

I just wanted to clarify this, as some may think the reference of 85 dB doesn't sound that high since many like music at 90 dB and above.

As for 75 vs. 85, common calibration tones are offset 10 dB to be easier on our ears and equipment. This is why usually we are asked to set everything to 75dB. But this should result in an 85dB average THX volume when in use.

Yes, this is what I meant.

I have calibrated my system to 75dB using the Denon test tones and my SPL meter. If I turn the volume control to 0dB, I easily hit average levels in excess of 105dB.

I'd like to hear more opinions on what the volume control calibrations mean. I'm starting to think that maybe it's referenced to the voltage across an 8Ohm load with a known frequency.

I am curious what SPL levels you are witnessing when you turn your volume control to 0dB.

Geezzzz
you all gonna be deaf
I am -10 to -20db I would say -15bd is pretty good for me for movies. hell I go louder and the other half is freaking.
Darn 0db gotta be louder than 85db I have a Denon 3803 and at 0db they can hear me across the street

I was tweaking on the levels once with a cd playing, pushed the wrong button and accidently kicked the processor out of calibration mode into cd mode with the vol at 0. I will never do that again. As rosane rosanadana used to say- "I THOUGHT I WAS GONNA DIE" I read a warning about that in the manual later. Thank god no one else was home.

David,

Wait a minute. Am I missing something here? Before calibrating my system with the test tones, should I be setting my main volume to 0dB??? I didn't think the main volume control was in the circuit during calibration.

BTW, I normally listen to music with the volume set to -25dB and movies -20dB.

If you want to be a purist to Dolby standard you would set the volume to 0 then calibrate at 85db not 75db. Most people calibrate at 75db to preserve their hearing.

I think the volume db settings on receivers are just arbitrary numbers that don't really mean much. These numbers vary between brands. Much better off using an SPL meter to calibrate. I think we've had some threads on this in the past. The volume numbers don't really indicate reference levels.

I don't think it is even possible on some receivers. My Onkyo cannot be calibrated in this way, at least not that I am aware of. I just put the main volume up till I reached 75db and level matched all speakers using the receivers test tones and spl meter.

Its not possible on many receivers. Once upon a time when this spec was developed, the thought was for manufactureres to adhere to a "standard" calibration reference ie. 0 and 85db... which evolved into 0 and 75 db... which has become every manufacturer for himself.

As long as the speakers are level matched and you have room on the receiver volume its all good.

Hey I just noticed I turned from a "local" into a "devotee"...I prefer "local".

I think I agree with you there. If I set my volume to 0dB and then try to calibrate my speakers to 75dB, I'll run out of attenuation on my channel levels.

My Denon Auto Channel setup calibrates everything to 80dB, when I verify after using my SPL meter. However, I usually do it manually using 75dB. The problem with 80dB is that it then has my speakers set so high that I run out of volume.

And what do you set your main volume control to before you calibrate?

This depends on the receiver/processor. Most of them that I have seen don't require you to adjust the volume before calibration. On mine, upon entering the reciever internal test tones the volume is internally auto set to 0 dB. I can manually turn the knob down while the tones are playing to verify this. And as I said before, many offset the level by 10 dB so that you can use a 75dB tone to calibrate to, that is translated to an 85dB level when in use.

Bottom line on calibrating is to go off of your receiver manual as to how the calibration should be done.

Oh, and yes I agree that listening at 0 dB is a bit too loud for me too. I'm usually around -7 dB for movies, and anywhere from -15 to -30 dB for music.

If you use the Denon Auto Setup, it does not matter. It automatically adjusts the volume for you to what ever was decided by Denon. The end result is an 80dB SPL from the primary position.

I usually tame that down to around 75dB once the Auto Setup is complete. I've tried the whole adjust the left speaker to 0dB first and then the rest of the speakers after that. Like Jakeman said, the end result and that your speakers are calibrated the same, to whatever level.

Mo, the numbers on the volume setting have no absolute meaning except that at a given input voltage the bigger ones are louder than the smaller ones. Some receivers of course don't use the - to 0 to + format(one of my receivers goes 1 to 79), but it doesn't make any difference. As to your question about what SPL levels would be heard with the volume at 0dB(when applicable), I'd say that it would depend on the dynamic range of the material being played, and on the very widest range classical material(rare)it could vary from a barely audible(in a very quiet room)40dB up to a brief 110dB peak. Much pop music is almost uniformly loud and has very little dynamic range, so even if the listening was at an extremely loud 90dB average, there might be no peaks above about 95dB. My own classical music listening when "loud" is at an average of about 80dB(using less than 1 watt), and hits brief peaks in the 100dB area on some compositions.

Of interest on the question of sound levels was Alan's discussion in the March newsletter .

When something is labelled 1 to 79, I realize that there isn't any physical meaning behind the numbers because they are dimensionless. But when I look at my Denon and it gives me the number in units of dB, I have to wonder what the engineers were thinking. There must be a reason behind labelling the numbers in dB. I still think it's related to the voltage across an 8 Ohm resistive load with a signal of known frequency and amplitude. Now what that translates to in the real world is a mystery to me.

Didn't the dB scale at least <i>used to</i> correlate to the amount of attenuation applied to the pre-amp's output signal?

At -&#8734;dB, the signal is fully attenuated/muted.
At 0dB, the signal is passed unaltered at line level.
At + dB levels, the signal is being boosted.

One would think this is still the case, no?

For those who said we would be going deaf with our receivers calibrated so 0 = 85db average, I guess I should have mentioned that I don't ever actually listen with it set at 0.

I never thought about manually setting zero to be a lower number. Makes sense but I guess I don't really care if I am always set at zero. I'm always playing with it anyways.

Wife comes in....Wife goes out....Wife comes in....Wife goes out.

Do I set it louder or quieter when the wife comes in? That is the question. heh heh.

What would be cool would be a receiver that allows a remote to set volume to a predetermined level with one button press instead of just moving it up and down.

That sounds logical. I don't know if it's true but there's some logic there. Now what does that mean practically in the real world?

It means don't worry about the numbers on the volume display. Pretend you're living in the past and there's just a tick mark on the knob and 7 o'clock is just right.

But these go to 11...

I don't even worry about what the number says on my pre/pro anymore. I just turn the volume up to where I like it and where I think its loud enough. The only thing that the numbers matter is when you calibrate it to get it to certain spl for movies and use that setting for most movies as reference, if its too loud turn it down some. The numbers are meaningless nowadays for me.

The numbers are also handy when you want to set the volume before the sound starts coming out, so you don't either scare people or miss the first few seconds while you sort through the remotes.