Where do I start? speakers!!!

[william13]

Originally Posted by jfray

Bill, I am not sure but I can do a frequency sweep (if I can find my test tone disc.....) (At 8Hz I think that you will need more than one G1 to hit 105db!) The actual speaker will be barely moving in and out at 8Hz. The biggest thing to consider is that your wife will not be HAPPY when you blow all of her china off the wall with your simulated cannon fire! ......

I set the thermostat to 74 and she does 73. I like 85 db listening and she likes 80db. Its an issue.

But what i am really trying to do is choose my music appropriately for my setup. For example I know I will not do cannons. That was just an example. What I really wanted to know is can my setup handle 85 db music with occasional 20 db peaks.

[chessman]

Bill, let me try to answer some of your questions.

1) Most music is no lower than 40 H (the low note on a piano, IIRC).

2) I have two subs (JL Audio F113's sporting 5,000 aggregate watts) integrated with a Bryston 10B-Sub active cross-over and placed in a well trapped room. There is NO WAY I could hit 105 dB at 8H, nor would I want to if I could. Real cannoneers wear earplugs for a reason.

3) As said above, when a sub is well integrated in a two channel system you do not know it is there until you turn it off. It adds to the sound stage, removes harmonic distortion in the midrange, and takes some load off your amps (in effect giving them more headroom for better dynamics), but it does not rumble.

4) Distortion in a two channel system is a sign that something is wrong. It is usually a speaker trying to do something outside its physical limits - like imitating the transient response of a cannon shot. Clipping an amp is a great way to get distortion that then kills the speaker - like trying to get 105 dB of 8H sound out of a speaker diaphram that is not the size of a Volkswagen.

5) Actually the great danger to hearing in our hobby is that you get the system to sound so clean that there is no distortion at high volume, which fools you into playing it too loud. Sustained listening at too high a volume can cause permanent hearing loss.

6) The "hit you in the chest" bass that movie nuts like (like me) is actually mid-bass, say 50H to 150H. A subterranean subwoofer can be felt, but not as a thump to the chest.

Hope that helps.

[william13]

Originally Posted by chessman

Bill, let me try to answer some of your questions.

1) Most music is no lower than 40 H (the low note on a piano, IIRC).

2) I have two subs (JL Audio F113's sporting 5,000 aggregate watts) integrated with a Bryston 10B-Sub active cross-over and placed in a well trapped room. There is NO WAY I could hit 105 dB at 8H, nor would I want to if I could. Real cannoneers wear earplugs for a reason.

3) As said above, when a sub is well integrated in a two channel system you do not know it is there until you turn it off. It adds to the sound stage, removes harmonic distortion in the midrange, and takes some load off your amps (in effect giving them more headroom for better dynamics), but it does not rumble.

4) Distortion in a two channel system is a sign that something is wrong. It is usually a speaker trying to do something outside its physical limits - like imitating the transient response of a cannon shot. Clipping an amp is a great way to get distortion that then kills the speaker - like trying to get 105 dB of 8H sound out of a speaker diaphram that is not the size of a Volkswagen.

5) Actually the great danger to hearing in our hobby is that you get the system to sound so clean that there is no distortion at high volume, which fools you into playing it too loud. Sustained listening at too high a volume can cause permanent hearing loss.

6) The "hit you in the chest" bass that movie nuts like (like me) is actually mid-bass, say 50H to 150H. A subterranean subwoofer can be felt, but not as a thump to the chest.

Hope that helps.

Articulate as ever Randy; So if using high powered amps is not for the purpose of blowing out your tympanic membranes at 105 db was is it for? I am being tongue in cheek but when does the need for power become a reality.
On another note seems these subs are pretty much universally embraced. Can you tell me a little more about mid-range harmonic distortion?

[chessman]

Originally Posted by william13

Articulate as ever Randy; So if using high powered amps is not for the purpose of blowing out your tympanic membranes at 105 db was is it for? I am being tongue in cheek but when does the need for power become a reality.
On another note seems these subs are pretty much universally embraced. Can you tell me a little more about mid-range harmonic distortion?

Bill, ok, I will try, but I am nearing the edge of my technical knowledge, so if I misstate something, someone please correct me.

1) It takes more power (watts) to make a lower efficiency speaker play as loudly as a higher efficiency speaker.

2) Volume stated in dB (Decibels) is actually logarithmic, thus a 10 dB increase results in double the volume.

3) A 3 dB increase requires double the power, but only sounds 1.23 times louder.

4) So to get to double the volume, you have to increase the dBs by 10 times and increase the power by 100 times.

5) A musical event that is suddenly louder (like a cymbal crash) requires a fast and sufficient jump in power to achieve it. On a graph it would look like a spike with a curved top towering over the wave form. If the amp does not have enough power, it stops trying (clips) and the spike has a flat top (the dreaded square wave that eats tweeters).

6) It also takes power to control speaker diaphram movement. High notes barely move a diaphram and are able to be controlled at lower power. But real low notes require a large surface to move fast and precisely, which just gobbles power. That is why the same speaker will sound like the bass got better when a high current amp was added to the mix (among other things, which we will pass for now).

7) Bottom line on power: more power is not for playing louder (1000 watts only plays 3 dB louder than 500 watts), but is instead for control, transient response, and safety from clipping.

8) Because bass notes are hard to produce they take more power, which when insufficient leads to distortion. Let's say you have that distortion at 40H. There will also be distortion of some degree at 80H, 160H, 320H and so on, because of harmonics. When a sub does a better job of producing the low end musical notes, there is less distortion of them, and less harmonic reproduction of them.

9) Small rooms also have standing wave issues that relate to mid-bass distortion, but that is not fixed with amp power, but instead requires bass trapping.

Hope that helps.

[william13]

I again commend you for your articulate organized explanation. I am getting a real good feel for the qualitative points you have made. I think the quantitative questions I have will be solved by more experience.

I meant (additional questions)

[jfray]

Originally Posted by jfray

Bill, I am not sure but I can do a frequency sweep (if I can find my test tone disc.....) (At 8Hz I think that you will need more than one G1 to hit 105db!) The actual speaker will be barely moving in and out at 8Hz. The biggest thing to consider is that your wife will not be HAPPY when you blow all of her china off the wall with your simulated cannon fire! ......

Bill,
I could not fine my test tone CD so I am not sure how loud the G1 will play a 10Hz (I know it will not be near 105db). I do think you will be happy with a sub.... Randy had a good explanation on the fact that power consumption and how loud a speakers plays is not linear.

[rbbert]

I'm pretty sure that a 10dB increase requires 10 times the power, not 100 times.

[Arj]

Originally Posted by rbbert

I'm pretty sure that a 10dB increase requires 10 times the power, not 100 times.

I think the thumb rule is doubling the power for every 3 DB. .. So approximately 10 times may be right.

Sent from my iPad using A.Aficionado

[chengisk]

Originally Posted by jfray

Bill,
I could not fine my test tone CD so I am not sure how loud the G1 will play a 10Hz (I know it will not be near 105db). I do think you will be happy with a sub.... Randy had a good explanation on the fact that power consumption and how loud a speakers plays is not linear.

Here is a link I use. But I am not so sure if that is what you are looking for.

Stereo System Test & Analysis Tones by Nino B.

-chen g