"Headroom" - what does it sound like to you?

[pauln]

Headroom is the overall available reserve to play louder - if you set the voulme so that the quietest sounds are quiet then there is plenty of dynamic space (it is mostly in the first watt). A 4 watt SET with big Klipsch will spend the vast majority of the time below the 1st watt - within the first 1/4 to 1/2 watt, which would give almost 12dB of reserve for peaks.

I think if you average 98dB you are playing too loud. Music 88dB avereage should sound perfectly comfortably loud and realistic for someone with unimpaired hearing.

[DrWho]

The upper limits of the dynamic range of any digital medium is still 0dBfs.

True, but any good recording isn't going to be sitting at 0dB for the entire album.....so if the "average" sound is recorded around -20dB, then you can have 20dB peaks. I have some material where the sound starts off at -60dB and then there are quick transients going up into the -5dB range. If I bring the original sound up to a good level like 70dB using the gain on the preamp, then I better have enough headroom on the amp to deliver over 120dB to the speakers.

Though I stated it indirectly, the 0dB limit on the medium may be true...but you are still able to adjust the pre-amp gain. But yes, we could record a test tone at 0dB and then find the maximum volume capable of our system, and then just make sure we have enough headroom based on the gain we're implementing with the pre-amp.

[cwop]

"If you play Khorns at 88db SPL and sit 12 feet away and want to cover music with a 10dB "dynamic range" you only need 8 watts. But if you want to cover music with 20dB range, you need 80 watts! Now raise the average SPL up to say 95dB with the same 20dB dynamics and suddenly you need 400W!"

This would only apply as a 'free space' calculation with a point source, it would not be relevant for a room. An accurate way to assess the reverberant sound field developed in a 3000 cu.ft.room with average furnishings is to use the figure of .5 (point five) acoustic watts for a reverberant SPL of 100dbc in this same 'average room' . The acoustic power output from these horns with the mentioned powers would be huge! Acoustic Research did a study on this years ago and arrived at these figures, and this was using 1% efficient acoustic suspension speakers! Of course with this 'low' efficiency the sealed boxes were fed 50 watts for the mentioned sound levels. I dont think those speakers would have taken this power for long.........Horns and the beloved 'flea powered' bottle amps would do well most likely for short duration loud peaks.......

[Parrot]

There are a lot of misconceptions about power requirements. I used to believe them till I did do the math. I got those misconceptions here. The usual line goes "Klipsch speakers are so sensitive that you do not need much power." Please be careful with what you tell people.

Well said.

I wish I had a dollar for every post I've read here that includes something along the lines of: I am no headbanger and have a normal sized room and therefore I estimate that I could get by with a 1 watt amp (even though I use a 50-watter).

[Parrot]

1. Clarity - how much fog, haze, film and smudging is on the "glass" I am looking through? Transparent or opaque? (Dark or slightly opaque amplifiers create massive listening boredom for me in no time at all. They don't offend, they simply don't excite. 90% of amplifiers I have owned have this fault above all others.) 2. Livliness - (microdynamics) is the amplifier responding to the slightest subtleties? Does the intake of breath quiver and quake like a real breath, or just sort of generically "shoosh"? 3. Dimension, space and layering - from front to back are tones staying in the proper layer, or moving forward and back, or worse yet, layers are collapsed into a thin veneer? 4. Natural tone - is the tone natural or overly polished, dull, bright, dark? 5. Distortion - can I detect objectionable distortions? 6. Balance - do I find myself "noticing" or thinking about, or analyzing, the treble, the midrange, the bass, or some particular subset of the sound, or do I very quickly hear only the music. If anything sticks out, or brings attention to itself, I won't like it - too HiFi for me. (I am also a firm believer in the old "magic number" which holds that any limitations in bandwidth should be equal at the top AND bottom for most natural sound. 7. Noise(s) 8. Range - does it sound good at very low powers and at powers near it's maximum? Or, does it fall apart at one of those extremes? Small amplifiers should clip very gracefully. 9. Power - is there enough at my listening levels? 10. Manners - does it do anything weird at turn on (thumps, squeels), or turn off, or after clipping, or during stress, or when heated up and so on. (I've had some expensive amps with very, very bad manners.)

That's a well-thought out list.

Would anyone here insert into the list: Price - must be $30 or less. If not, the Sonic Impact is best forgotten.

[ben.]

This wasn't meant to be thread about power requirements. It's fine that it has become one of sorts, I guess. My aim was to find out what made someone proclaim that their system had headroom, and what they heard in association with that.

I'll stand by my statement that if you can damage your system with a steady state signal at 0dBfs, then you deserve to be buying parts the next morning. And a 30dB transient (30dB referenced to what? I assume the average level of the recording, but since you didn't indicate that it's somewhat meaningless) will still never exceed 0dBfs. A situation where you can turn up the preamp gain as DrWho mentioned would indicate exactly the miscalibration I speak of. Maybe they'll get to that senior year...

Telarc puts that warning on 1812 to sell records. It works.

[billyjoe72]

Alot of subjective info for one to shuffle through and absorb. I do know my truck has plenty of headroom.

[DrWho]

A situation where you can turn up the preamp gain as DrWho mentioned would indicate exactly the miscalibration I speak of.

I wouldn't go so far as to call it miscalibration.....let's say you find the spot on the preamp dial just below the point where a 0dBfs signal clips your system. For the sake of analogy let's say the volume at this position is 100dB. If we listen to most of our music around 80dB and only have 20dB peaks to worry about, then we will be fine. But let's say you're listening to something recorded at -40dBfs. For the same position of the volume knobs, your average output will be 60dB (most likely too quiet on everybody's standards). There is nothing wrong with boosting the by 20dB with your preamp's gain to get it back to 80dB in the room, but you better hope that there aren't any peaks over 20dB....or if there are, you better hope they are very fast and do not clip anything (or get by without any audible clipping). Most speakers can't track peaks this fast though....for instance, the piece of music with the 50dB transient. With a 1000W pro amplifier (with huge damping) I can only get 30dB of the transient out of my Chorus II's (so in that millisecond the sound is getting acoustically rounded off). (this is measured by mic into an FFT where I don't have to worry about meter delay...but there will be delay as measured by the mic). Btw, this was measured at frequencies the squaker would be reproducing (where hornloading is advantageous to such a test). Anyways, the point is that if the speakers can't handle the sharp peaks, then there is no need for the amplifier to be able to. However, let's not confuse short signal response with the overall concept of headroom. A piece like the 1812 overture has well over 40dB of dynamic range between the quietest and loudest sustained parts of the piece...so because it's sustained volume you need to have the dynamic range available (because I'm most certainly not going to enjoy listening to the quiet parts at 60dB....if I start at 80dB then my ears will be bleeding at the end).

Back to the 0dBfs topic...you also don't 'always' want to set your preamp gain to the "max level", especially when that max level is pushing like 130dB.

So though it is a good rule to never turn the gain up beyond the "max level" there are times where the rule can be broken, so really it can't be construed as a miscalibration. However, "mixing with emotion" (which is what I like to call it) and "trying" to "push" the system beyond its limits is just absurd. It's one of those things where it will be realized, "hmmm, If I go beyond this point bad things happen" but the person will still think, "I can still get another ounce out of it." I know people aren't fond of science and I know I'm rambling way too much, but setting the gain structure is quite easy - and if in the end you don't have enough, then fix the problem at its source and get devices with more gain (ie a better amplifier).

This is my checklist for finding an amplifier (listed in order):

1. Headroom - if it ain't gonna be linear in the range of volume to which I listen, then I don't want to bother with it. (The "formula" I use is to find the loudest peak that I might ever experience...then allow for 6dB of headroom beyond that point)

2. Noise floor - if it makes audible noise I don't want it (fan noise, amp hiss, buzz, etc etc...). The overall resolution of the system is dictated by its noise floor.

3. Transparency - is the amplifier behaving like an EQ? Or straight wire with gain?

4. sound quality - Does it enhance the enjoyment of the music or is it so "accurate" that it reduces my enjoyment? This is where I want that touch of warmness that isn't to the point of not being transparent.

5. Behavior when overdriven - is it going to blow stuff up, or is it still going to sound "good"? I believe "overdriven artifacts" are always present at all volumes, just that they are relatively much lower until real clipping starts to happen. Most amps that behave well when clipped ironically tend to be 'transparent' with good 'sound quality'

6. Build Quality - is over heating going to be an issue? Is the amplifier going to last me a long time, or will it be hard to maintain?

7. Aesthetics - smaller is usually better if it doesn't sacrifice any of the above. And it never hurts to have an amp with a pretty face and fancy lights.

[MrMcGoo]

I agree with DrWho with one major clinker. Modern digital processors have acoustic room correct capability. They can add 10 to 12 db of boost to digitized sound at various frequencies. On top of that, my Pioneer can add 6 db of dynamics on SACDs. These systems are on Denon, Lexicon, H/K, Meridian, Pioneer Elite and Yamaha receivers/processors amongst others. Greater care is needed with such systems.

Klipsch will use the current Yamaha flagship with 4400 watts of outboard amplification at CES in January. (Klipsch is "partnering" with Yamaha these days.) The room correction feature adds a new dimension to headroom requirements and clipping. Why take the risk? The sound takes you to a new level of quality, even in treated rooms.

So, you can go over 0dBfs on your CD when listening to music on such a system. The DACs meet the wider dynamic range requirements of DVD-A and SACD on receivers with i.link or Denon Link. The idea that 0dBfs capable systems cannot be clipped is a potentially dangerous misconception. Don't let the tail wag the dog. Clipping and headroom need to be analyzed from a complete SYSTEM point of view.

Bill

[ben.]

I'm not sure how many more ways I can rephrase the concept, so I give up. I'm sure you two think I just don't understand, and I'm also resigned to that. I suppose this was an inevitable result of an open-ended question on the Klipsch forum.

[DrWho]

I'm not sure how many more ways I can rephrase the concept, so I give up. I'm sure you two think I just don't understand, and I'm also resigned to that. I suppose this was an inevitable result of an open-ended question on the Klipsch forum.

no no no...I was totally agreeing with you! I just had some issues with the blanket statement of it being "miscalibration"...and then proceeded to ramble on like I always do []

[leok]

Ben,

Not too sure what you're looking for, but I'll give it a try. My favorite system is the RF-7s driven by the 3.5W 2A3 amp. The system has sufficient power (current and Voltage) for a lot of what I listen too under most conditions. In those cases the system has sufficient "headroom" it doesn't clip or compress the sound.

In some cases I may have the volume up a bit higher than usual and notice the onset of compression, "glare," (the sound of a tube amp running out of Voltage or current "headroom"). In that case I can either 1) turn the volume down a click or two or 2) get a more powerful amp (pp, Tripath, or Crown).

Headroom is sufficient current and voltage, available in the amp's output to accurately follow the program material. If you need +/- 5V and 1A to accurately drive your speaker and your amp has just that capability then you have sufficient headroom for that occasion with that equipment. If you decide to turn up the volume you'll run out of headroom and will clip (or begin to do the compression thing tube amps do which I consider clipping). If you turn the volume down below the +/- 5V and 1A requirement you have a little excess headroom which is of no particular sonic value but might be fun to "know." If you need 5a and 25V capability then that's what you need. If you have it, you have sufficient "headroom" and the sound is good. If you don't, then you need a bigger amp.

If you need +/- 5V and 1A and have an amp that can deliver 5a and 25V you'll never run out of headroom, but you might find the amp has some distortion and noise at the lower levels creating a gritty or harsh sound. In that case you need an amp that better matches your requirements: say, one that can deliver 5a and 25V and still handle the 5V 1A and below OK, or one down to a +/- 5V and 1A that also handles lower levels well.

Leo

[ben.]

DrWho, I appreciate the clarification. I just meant that for the undisciplined among us, it's wise to calibrate the gain structure in such a way that the system is safe as a whole. Mine is, as I have a 2-yr old that is quick on his feet and fascinated by knobs and things he mustn't touch, among other things. Despite the odd software that will add gain above the full-scale digital level, the general point is valid, I think. If you've got some box that can add 6dB, well, you'd better read the manual and adjust accordingly. It may be enjoyable to poke holes in a generalization with specific exceptions, but it's only good form to do so while noting the more general facts.

Leo! It seems a coon's age since I've seen a post from you. You may be thinking the same... Anyhow, your subjective and objective descriptions are spot-on. I was really just looking for a description of what leads folks to declare that their system has headroom, and what they subjectively hear that contributes to that assessment.

[Jeff Matthews]

This headroom topic was covered in some detail in the "I bought KHorns" thread. Without headroom, when you turn up the volume, the "softer notes" converge at the top of your power output with the "loud notes." Therefore, separation is lessened, and dynamics begins to fall apart. The converging loudness across the spectrum muddles the sound. Many think it's distortion.

[MrMcGoo]

DVDs have a dynmic range of up to 144 decibels while CDs are limited to 96 decibels, if memory serves. This has profound implications for headroom requirements.

We can reproduce movies at home to essentially the same or higher levels than in commercial theaters, but there are very real risks that come with the opportunity. Most home gear is not designed to help manage the dynamic range with anything other than the volume control and a sound meter. Most do not realize how dangerous the room correction can be to speakers and amps, yet most mid-fi receivers sold today have the feature.

Pioneer was the first manufacturer to use room correction on receivers. Pioneer blew it in the 4 series machines, because their receiver protection circuits were too sensitive with the room correction engaged. They had massive shut down problems till they tweaked their protection circuits. The 5 and 7 series are much better. My 5 series receiver runs at much lower temperatures. Even a highly sophisticated manufacturer failed to see the headroom and resultant thermal implications.

Adequate headroom may mean that your machine does not shut down under a normal load.

Bill

[Painful Reality]

Adequate headroom may mean that your machine does not shut down under a normal load.

Front load washers...

Nothing beats them.

[Painful Reality]

double post...

[ben.]

My Whirlpool kicks your Maytag's a$$.

[Painful Reality]

My Whirlpool kicks your Maytag's a$$.

There is no such things as a "best washer"

What type of cloths do you wash?

Colors?

[ben.]

DVDs have a dynmic range of up to 144 decibels while CDs are limited to 96 decibels, if memory serves. This has profound implications for headroom requirements....

What you're missing is that DVDs are not meant to get louder than CDs. The noise floor is supposed be lower.

0dBfs stands for 0 decibels full scale. This is the highest level recordable on any digital format. Any levels are expressed in a number below that absolute highest possible level on that medium. What you choose to do with that fact in the context of your playback chain is entirely your perogative. This would include such atrocities as "room correction" from Pioneer as well as turning your preamp up too loud.

I thought you guys that championed the whole high power brute force idea understood at least a few of the reasons why the idea has some merit. I guess some do, some don't.