What is Sound Pressure Level?

[JBL 4645]

Altec consultant Robert Heiblim explains about sound pressure level that we like to listen to.


http://www.youtube.com/watch?v=nC9z1zwryz0


http://www.youtube.com/watch?v=udedV3rkIx0&feature=related

:xmas::window:

[Akira]

This is supposed to be educational :confused: ...waste of time.

3db is not twice as loud

[hjames]

We've been over this before Ashly -

To double the apparent volume requires 10db ... not 3 db
Believe me or don't, Ash, I don't really care - it just IS.
get some technical books if you need to verify this.

or read this ...
http://en.wikipedia.org/wiki/Decibel

The decibel (dB) is a logarithmic unit (http://en.wikipedia.org/wiki/Logarithmic_unit) that indicates the ratio of a physical quantity (usually power (http://en.wikipedia.org/wiki/Power_%28physics%29) or intensity (http://en.wikipedia.org/wiki/Intensity_%28physics%29)) relative to a specified or implied reference level.

A change in power ratio by a factor of 10 is a 10 dB change.
A change in power ratio by a factor of two is approximately a 3 dB change.
More precisely, the factor is 103/10, or 1.9953, about 0.24% different from exactly 2. Similarly, an increase of 3 dB implies an increase in voltage by a factor of approximately http://upload.wikimedia.org/math/b/f/c/bfc552de0f2e3353d96542d0e6382405.png, or about 1.41, an increase of 6 dB corresponds to approximately four times the power and twice the voltage, and so on. In exact terms the power ratio is 106/10, or about 3.9811, a relative error of about 0.5%.

[JBL 4645]

Nice bit of computer modelling.

http://www.youtube.com/watch?v=GLojVRZrOWY

This one has that one, extra push over the cliff these go to "11"

http://www.youtube.com/watch?v=At887GsraAQ
:xmas:
:sleigh:

[timc]

To make it VERY simple.

SPL (sound pressure level) is JUST what it says. The pressure generated by the sound. This is related to the lowest noise we are able to detect. This level is standardized to 0dB SPL
= 20uPa. The relation between the numbers are that the SPL rises with the square of the pressure.

A 3dB equals a doubling/halfing in sound POWER, not level. The percieved doubling to humans is right under 10dB. Think its 9,98 or something like that. This is because our ear also work logarithmically.

So. What can we see from this. Well, it is very important not to mix pressure, and sound pressure level. The sound pressure level is always positive (given that is it pressure^2). The pressure on the other hand, oscillates between positive and negative. Its like a high/low pressure weather system, continually, and gradually changing places. The result of this is that the air isnt actually moving towards you when you listen. The waves just ripple towards you, and the air molecules are just vibrating betwwen the pressure max and min, at the time the soundwave passes through their position.

[ratitifb]

The sound pressure level is always positive not always, depending on the reference you have chosen. For exemple, if you choose 1Pa as reference level for dB scale, a lot of sound pressure levels will have a negative SPL (dont' forget 20µPa is equivalent to -94dB re 1Pa) ;)


LOUDNESS in sones is the best way to express the perceived hearing level when doubling loudness is twice as loud :bouncy: (equivalent from 6 to 12dB more ... depending on the spectra characteristic of the sound source)

[JBL 4645]

Hey guys I’m not looking for answers? That's why I posted the two videos. I found the two videos a bit unsatisfying they weren’t thorough enough in detail with using test equipment, that's how you get the message across.

It was just a load of talk "use AAA batterers" what? I thought the video was a joke. I think, Carl Sagan could have explained in a more thorough and entertaining way.
:xmas::window:

[timc]

not always, depending on the reference you have chosen. For exemple, if you choose 1Pa as reference level for dB scale, a lot of sound pressure levels will have a negative SPL (dont' forget 20µPa is equivalent to -94dB re 1Pa) ;)




You misunderstand me. The SPL can be negative on a relative scale, but never on an absolute scale. I was thinking physical here. On the other hand, the Pressure is negative in an absolute manner.

[timc]

Hey guys I’m not looking for answers? That's why I posted the two videos. I found the two videos a bit unsatisfying they weren’t thorough enough in detail with using test equipment, that's how you get the message across.

It was just a load of talk "use AAA batterers" what? I thought the video was a joke. I think, Carl Sagan could have explained in a more thorough and entertaining way.



Erh.....Then what was the point of the post? Just saying that "here is another guy who doesn't really know?

If your intention was to make fun of the guy, you should have stated so in your first post.

[Rolf]

How hard can it be? To increase the level 3db you must double the power they can do. To double by 10db you need about 3,5 more power from your amp. Simple. Here is an example:

You use 10W to produce 100db. 103db you must have 20W. 106db you need 40w, and so on. That is why you need a large power amp. An "ineffective" speaker witch can only give 90db using 1W, you can figure it out yourself.

This has been discussed many times before.

[timc]

To double by 10db you need about 3,5 more power from your amp.




I guess you mean 10 times more?

[Rolf]

Sorry for error. Yes. But the rest should be correct.


I guess you mean 10 times more?

[Ruediger]

A power ratio is power1 divided by power2, P1/P2.
A voltage ratio is voltage1 divided by voltage 2, U1/U2.

x dB = 10 log10(power ratio) = 20 log10(voltage ratio)
The Bel designates a logarithm, it is not a real unit, it can be omitted, does not need to be cancelled.

Example: 10 dB = 10 log10(P1/P2),
ergo 1 dB = log10(P1/P2)
10**1 = 10**log10(P1/P2)
10 = P1/P2

Another one: 10 dB = 20 log10(U1/U2),
ergo 0.5 dB = log10(U1/U2)
10**0.5 = 10**log10(U1/U2)
3.16= U1/U2

So 10 dB is a power ratio of 10 and a voltage ratio of 3.16

ruediger

[Rolf]

This was to complicated for me. Please explain for the ones deadly.



A power ratio is power1 divided by power2, P1/P2.
A voltage ratio is voltage1 divided by voltage 2, U1/U2.

x dB = 10 log10(power ratio) = 20 log10(voltage ratio)
The Bel designates a logarithm, it is not a real unit, it can be omitted, does not need to be cancelled.

Example: 10 dB = 10 log10(P1/P2),
ergo 1 dB = log10(P1/P2)
10**1 = 10**log10(P1/P2)
10 = P1/P2

Another one: 10 dB = 20 log10(U1/U2),
ergo 0.5 dB = log10(U1/U2)
10**0.5 = 10**log10(U1/U2)
3.16= U1/U2

So 10 dB is a power ratio of 10 and a voltage ratio of 3.16

ruediger

[Ruediger]

A power ratio is power1 divided by power2, P1/P2.
A voltage ratio is voltage1 divided by voltage 2, U1/U2.

x dB = 10 log10(power ratio) = 20 log10(voltage ratio) <<< THIS IS THE DEFINITION OF THE dB
The Bel designates a logarithm, it is not a real unit, it can be omitted, does not need to be cancelled.

Example: 10 dB = 10 log10(P1/P2), <<< DIVIDE EQUATION BY 10
ergo 1 dB = log10(P1/P2) <<< RESULT OF DIVIDE
10**1 = 10**log10(P1/P2) <<< RAISE 10 TO THE POWER OF THE LEFT RESP. RIGHT SIDE
10 = P1/P2 <<< RESULT OF RAISE

Another one: 10 dB = 20 log10(U1/U2), <<< DIVIDE EQUATION BY 20
ergo 0.5 dB = log10(U1/U2) <<< RESULT OF DIVIDE
10**0.5 = 10**log10(U1/U2) <<< RAISE 10 TO THE POWER OF THE LEFT RESP. RIGHT SIDE
3.16= U1/U2 <<< RESULT OF RAISE

So 10 dB is a power ratio of 10 and a voltage ratio of 3.16

ruediger

[timc]

Ill simplify.

1: The power (watts) is given by R*I^2. R is the impedance, and I is the current.

2: The current is given by U/R. U is the voltage (RMS) on the output of the amplifier.

To get one watt at 8ohm, you need 2.83V:
Current from 2: U/R = 2.83/8 = 0,35375 Amps
Power from 1: R*I^2 = 8*0,35375*^2 = 1 watt

Then multiply the power by 10 for 10watts.
Current from 1: P/R = I^2 = 10/8. This give I = sqrt(10/8) = 1.118 Amps
Voltage from 2: I*R = 1.118*8 = 8.944 Volts.

Ratio between power: 10/1 = 10
Ratio between voltage: 8.994/2.83 = 3.16


-Cheers

[Rolf]

Very well. Are you saying that my simple example is wrong?

[timc]

Very well. Are you saying that my simple example is wrong?

No, no. I was just trying to simplify Ruedigers math.

However, there is one thing worth mentioning. That is power compression. So at high levels, you don't actually get the sound power corresponding to the input power. Just another reason, to choose efficient speakers :)

[Rolf]

How right you are:D I have heard speakers that needs 200W just to make sound you almost doesn't hear. Imagine the amount of power then need to play 110db.;) If they can at all.:confused:


. Just another reason, to choose efficient speakers :)

[JBL 4645]

Erh.....Then what was the point of the post? Just saying that "here is another guy who doesn't really know?

If your intention was to make fun of the guy, you should have stated so in your first post.

I’m not making fun I thought it was rather dull and really expected a lot more.


How right you are:D I have heard speakers that needs 200W just to make sound you almost doesn't hear. Imagine the amount of power then need to play 110db.;) If they can at all.:confused:

I think Rolf thinking of (room nulls) where a frequency is so far down you can just barely hear it, (Is that right)?

The video did mention what some of know the high sensitivity the less power it will take to reach a certain level.

[timc]

I think Rolf thinking of (room nulls) where a frequency is so far down you can just barely hear it, (Is that right)?


That is not right. It was an exageration to make a point about low effiecency speakers

[Rolf]

Correct.


That is not right. It was an exageration to make a point about low effiecency speakers

[JBL 4645]

That is not right. It was an exageration to make a point about low effiecency speakers

I have set of low efficiency loudspeakers but I’m not grumbling. I also have a few high efficiency loudspeakers that would easily leave the smaller loudspeakers in the dust. But I’m not dissatisfied otherwise I would have changed them, years ago.

I think high efficiency starts in the 90db upwards and over 100db. Low efficiency loudspeakers under 90db?
:xmas::tree:

[timc]

I think high efficiency starts in the 90db upwards and over 100db. Low efficiency loudspeakers under 90db?


It is not that simple. Sensitivity is one thing. Another thing is the load the loudspeaker represents to the amplifier. So if you have 90db speaker, it could be more difficult to power than a 93db speaker. It depends on the impedance and phase of the speaker.

This is not related to watts and sensitivity as such, but since we don't have perfect amplifiers, it has to be considered.

[Allanvh5150]

A better rule of thumb:

Big speaker + big amplifier = loud

There are no other equations required.

Why use a small amplifier when a big one will work fine.................:)

[JBL 4645]

Al

You know what for a few years I ran the JBL sub on Marantz1050 and that is grossly under-powering it. I never noticed any issues and I had the sub up to 126dbc on VHS tape Final Approach (1991) afterburners on the SR-71, :bouncy: so how do you figure that? One might be some room gain and where the sub was located in the room, this was around, 2000?

I’m more worried when I see the barograph on Alesis RA300 reaching almost peak level and I’m throwing out at least close to 300watts. So god knows how many times I must have clipped the 1050 I never heard any popping sounds when running years back with around 65watts I think the Martatz1050 is rated at 65watts?

Edit: The link shows its ratings, thuo I read a few years ago it was rated at 65watts so now I'm confused? I wonder if there any on flaBay tonight?
http://www.vintage-audio.com.ua/en/cat/336/1528.html

Edit: Nope only 1030 http://cgi.ebay.co.uk/Marantz-Model-1030-Intergrated-amplifier-/280601686566?pt=UK_AudioTVElectronics_HomeAudioHiF i_Amplifiers&hash=item415529f226#ht_500wt_1076
One of the channels doesn't work, well it could be the volume pot that's the issue? I know I have a volume pot issue on mine but as long as I set it where I like it to be no problems. WOW 1975 35 years old.

Powers the JBL control1 rear back, (used to power the sides then I changed everything around) powers without any problems loud enough as the seating is closer to the surrounds, and they don’t need to be played at ear deafening levels. 85dbc to 90dbc peak is loud, they have reached somewhere over 100db I think that was on Flight of the Phoenix (2004).
:xmas::tree:

[Allanvh5150]

I tend to use very large amplifiers for everything. My 4 2235 sub speakers can each receive 500 watts. The system can run that loud but you would have serious hearing damage if you sat for too long. At "normal" volumes, the amps never get close to clip.

Allan.

[timc]

90dbC peak is not loud at all. Well, it depends on the frequency, but between 60Hz and 10KHz its not.

In general i agree with Allan. However high power amplifiers tend to have more noise at low levels. So for HF duty on high efficiency drivers, like horns, it could be counterproductive

[Ducatista47]

A better rule of thumb:

Big speaker + big amplifier = loud

There are no other equations required.

Why use a small amplifier when a big one will work fine.................:)
Because everything else being equal a lower power amp will have better sound quality. Don't argue with me, go argue with Nelson Pass about this if you don't agree. Of course I am assuming high fidelity is a goal here.

There is no substitute for efficient speakers when seeking quality reproduction. Without them it will be a struggle and a bigger compromise.

Depending on who is talking, high efficiency is 93dB, 97-98dB or over 100-101dB. Some horn fanatics believe less than 105-107dB is not in the hunt.

[Hoerninger]

There is no substitute for efficient speakers when seeking quality reproduction.
http://www.audioheritage.org/vbulletin/showthread.php?11909-Paragon-XXL&p=249122&viewfull=1#post249122

A full horn system is worth a try for those who did not know. :)
____________
Peter

[JBL 4645]

Because everything else being equal a lower power amp will have better sound quality. Don't argue with me, go argue with Nelson Pass about this if you don't agree. Of course I am assuming high fidelity is a goal here.


I looked up Nelson Pass and thought I was looking at the wrong person. Flipping heck he looks like, Ioan Allen.:D
:xmas::window:

[timc]

Because everything else being equal a lower power amp will have better sound quality. Don't argue with me, go argue with Nelson Pass about this if you don't agree. Of course I am assuming high fidelity is a goal here.

There is no substitute for efficient speakers when seeking quality reproduction. Without them it will be a struggle and a bigger compromise.

Depending on who is talking, high efficiency is 93dB, 97-98dB or over 100-101dB. Some horn fanatics believe less than 105-107dB is not in the hunt.

This is only partially correct. The thing about the amplifiers is correct, but there are som BIG but's here. To make a high effficiency system (>92-93db), you have to make som sacrifices as well. Horn loading is not without its problems, as pointed out by Geddes for instance. Voishvillo also have done extensive research on this.

So where does this leave us? It's all about optimization. A "normal" speaker done right, can sound much better than a horn system done not so right. And of course the other way around.

My personal belief is that a fully optimized horn/waveguide based system is superior to a fully optimzed normal speaker. The trouble is getting the horn system just right. That is harder than to make a good normal speaker in my oppinion.

[timc]

I looked up Nelson Pass and thought I was looking at the wrong person. Flipping heck he looks like, Ioan Allen.:D


You didn't know about Nelson Pass? The guy is a genius. Not to say that i always agree with him, but he has lots of great ideas. He is also among the most "down to earth" persons in the industry.

[JBL 4645]

You didn't know about Nelson Pass? The guy is a genius. Not to say that i always agree with him, but he has lots of great ideas. He is also among the most "down to earth" persons in the industry.

I'll take you're word for it. They're both geniuses its hard to believe they look similar. I'll have look for some technical stuff under Nelson Pass later on. I bet that big beefy amp next to Nelson costs a bomb!
:xmas::tree:

[Rolf]

Hi timc. From where in the world have you the information that high power amps have more noise at low levels?? I have had amps from 15W (FTC) to what I got now, 800W pr channel (FTC) and they have all been quiet at all levels. The profit of having large amps is that these never get stressed, because you only use a small part of their potentials. A small amp will clip very soon, and that is no good neither for the amp or the speakers.


90dbC peak is not loud at all. Well, it depends on the frequency, but between 60Hz and 10KHz its not.

In general i agree with Allan. However high power amplifiers tend to have more noise at low levels. So for HF duty on high efficiency drivers, like horns, it could be counterproductive

[timc]

Hi timc. From where in the world have you the information that high power amps have more noise at low levels??

This is quite common knowledge. The noise increases with the "specs" of the output devices. A transistor specified for, lets say 100V, have more self noise than one rated at 30V. So at low level the S/N ratio is lower. We are not talking about high noise levels regardless, but its there.

[Rolf]

I invite you to come to hear any noise from my two Perreaux 350P. They are quiet, except for some low "trafo noise", witch you can not hear when playing. I believe the "trafo noise" is coming because farmers in the neighborhood uses much power to keep a steady temperature for their potato's, vegetables etc. No such problems from spring to Autumn. The electric provider says ofcource no. I have been thinking about to install a "earth rod", connecting the amps to a separate grounding. Is illegil, but what the heck.


This is quite common knowledge. The noise increases with the "specs" of the output devices. A transistor specified for, lets say 100V, have more self noise than one rated at 30V. So at low level the S/N ratio is lower. We are not talking about high noise levels regardless, but its there.

[timc]

1: I invite you to come to hear any noise from my two Perreaux 350P.

2: I believe the "trafo noise" is coming because farmers in the neighborhood uses much power to keep a steady temperature for their potato's, vegetables etc.

1: I did not claim this noise would be a nuiscianse, but its the way it is. Would love to hear your system someday.

2: Sounds reasonable. Have you tried with a separation transformer (galvanisk skilletrafo)?

[JBL 4645]

Stop the thread! No just kidding. :D

I found thus video with Nelson Pass on youtube it runs for 59min 43sec so I’m going to settle back, watch and listen to what this chap has to say.


http://www.youtube.com/watch?v=-h04jeOR3gA
:happyh::tree:

[Ducatista47]

This is only partially correct. The thing about the amplifiers is correct, but there are som BIG but's here. To make a high effficiency system (>92-93db), you have to make som sacrifices as well. Horn loading is not without its problems, as pointed out by Geddes for instance. Voishvillo also have done extensive research on this.

So where does this leave us? It's all about optimization. A "normal" speaker done right, can sound much better than a horn system done not so right. And of course the other way around.

My personal belief is that a fully optimized horn/waveguide based system is superior to a fully optimzed normal speaker. The trouble is getting the horn system just right. That is harder than to make a good normal speaker in my oppinion.
I agree, but horns see limited use at my house. My 4345s are about 98db at the "top," the compression drivers and the ten inch cone, and 95dB for the 2245H. Since I biamp, not an issue.

My main system is a very high fidelity twelve inch full range driver/tweeter combo at 97-98dB.

Everything always involves some compromise in audio, but I have indeed found that the compromises are more serious, expensive and numerous with lower efficiency transducers and the electronics they require. They never seem to sound as good to me as the higher efficiency systems when everything is done right.

[timc]

As you see in my third quoted paragraph i fully agree :)

But its not an easy feat to achive

[Ruediger]

Some audiophile amps have capacitors which are too large. "More" is not always "better".

Have a look at http://www.kpsec.freeuk.com/powersup.htm, see the section "Smooting".

The larger the capacitors are, the shorter the charging time, and the larger the peak currents. Larger peak currents in shorter charging times means "steeper" pulses with more harmonics. This can become audible.

Ruediger

[timc]

The larger the capacitors are, the shorter the charging time, and the larger the peak currents. Larger peak currents in shorter charging times means "steeper" pulses with more harmonics. This can become audible.

Ruediger

This is not right. The larger the capcitor the longer the charging time. The charging time is given by T=RC for 63% charge. So you see, when the C goes up, the T goes up.

Or are you confusing the charge time, with the energy/time relationship (joules pr. time unit)?

[JBL 4645]

Edit: forget that last comment removed…I have resolved the issue video is continuing.
:happyh::window:

[Ruediger]

This is not right. The larger the capcitor the longer the charging time. The charging time is given by T=RC for 63% charge. So you see, when the C goes up, the T goes up.

Or are you confusing the charge time, with the energy/time relationship (joules pr. time unit)?

See the picture in the reference I gave, under "Smoothing". The larger the capacitor the SHORTER the charging time.

Ruediger

[JBL 4645]

In the video! Well the topic mentioned amps of different class amplifiers A AB C and D and (T?) is that right? Where one amp is going positive and the other negative?

I just buy them and hock them up that’s all. So since an amp is needed for (sound pressure levels) what is best amp just simple link to thread on this site would suffice. And the amp has to be for £200.00 because I’m cheap bastard.:D

At around 24min Pass mentions the inefficiency issue of amps, he keeps Altec and even brought a pair JBL L300 recently. Pass isn’t on this site? :D He seems like a mellow relaxed chap. I mean c:coolness::cool:l.
:happyh::presents:

[JBL 4645]

The video on youtube has locked-up again!:banghead: 33m00s SIGH I give up, and I was just starting to enjoy the video conversation.

Edit: No hold on SIGH if I jog the video bar across the a bit the video continues but it keeps locking-up at 33m00s
:xmas::tree:

[Rolf]

You don't know what you are talkin about ashley. What is your largets amp? in Watt (FTC)?


The video on youtube has locked-up again!:banghead: 33m00s SIGH I give up, and I was just starting to enjoy the video conversation.

Edit: No hold on SIGH if I jog the video bar across the a bit the video continues but it keeps locking-up at 33m00s
:xmas::tree:

[JBL 4645]

You don't know what you are talkin about ashley. What is your largets amp? in Watt (FTC)?

I don’t make the amps Rolf, I just buy the god damn things and wire them up. :D

I was thinking wow there’s so many different grades of amps out there. I don’t like tube amps because of the fragile glass tubes and I wouldn’t have one if one fell off the back of lorry for £10.00 pounds. I like transistors amps, just as someone else who doesn’t like transistor amps for maybe the same reasons?

There different breeds of amps out there made for different people with different tastes for different folks. Funny thing is we might be playing same LP or CD only on different amps and loudspeakers whether there JBL or other
:happyh::window:

[Rolf]

That is OK. BUT what is your amps rated? That was my question.


I don’t make the amps Rolf, I just buy the god damn things and wire them up. :D

I was thinking wow there’s so many different grades of amps out there. I don’t like tube amps because of the fragile glass tubes and I wouldn’t have one if one fell off the back of lorry for £10.00 pounds. I like transistors amps, just as someone else who doesn’t like transistor amps for maybe the same reasons?

There different breeds of amps out there made for different people with different tastes for different folks. Funny thing is we might be playing same LP or CD only on different amps and loudspeakers whether there JBL or other
:happyh::window:

[JBL 4645]

That is OK. BUT what is your amps rated? That was my question.

Mine are cheap brand and I’m not ashamed. Alesis RA300 Marantz 1030 and 1050

Brought as new for 2x and x1 brought used (2007) Alesis RA300 specs
http://www.alesis.com/ra300

Brought as second-hand (1990) x1 Marnatz 1030 specs
http://www.classic-audio.com/marantz/1030.html

Brought as second-hand (1990) x2 Marnatz 1050 specs
http://www.vintage-audio.com.ua/en/cat/336/1528.html
:xmas::tree:

[Rolf]

Alesis 90W. Marantz 1030: ?? W. Marantz 1050: 30W.

These amps will clip at about 10-12W continius power, making the sound no good. You need larger amps.


Mine are cheap brand and I’m not ashamed. Alesis RA300 Marantz 1030 and 1050

Brought as new for 2x and x1 brought used (2007) Alesis RA300 specs
http://www.alesis.com/ra300

Brought as second-hand (1990) x1 Marnatz 1030 specs
http://www.classic-audio.com/marantz/1030.html

Brought as second-hand (1990) x2 Marnatz 1050 specs
http://www.vintage-audio.com.ua/en/cat/336/1528.html
:xmas::tree:

[JBL 4645]

Alesis 90W. Marantz 1030: ?? W. Marantz 1050: 30W.

These amps will clip at about 10-12W continius power, making the sound no good. You need larger amps.

They’re used on a 4ohm load rated into 150watts so I should be safe with an 85db level of around 5watts at listening distance. If I push harder yes they’d be almost running on empty.

I’m going to revamp the amps sometime next year for control 1 and 5 with Behringer A500 for each LCR and later extra front channels, as well as for each stack of surrounds.

For the diy subs I’m looking at Behringer EP2000 which would be way than more than adequate.


http://www.youtube.com/watch?v=_BRv9wGf5pk
If it makes you feel I’ve got light sound reinforcement power! :D

This track jams okay on the control series with some sub bass extension and I’m not grumbling if the lows can reach, (if I wanted it so) 110dbc 115dbc bat that would be too damn loud and I’ve had the SPL db metre reading 126dbc once, no thanks once was enough.
:xmas::tree:

[Rolf]

Again: you have no idea what you are talking about. HI-Fi is for people who like music, and good sound. Do you even know what Hi-Fi means? It means "to get as close as possible to the real thing". Your equipment doesn't even are close to this, but I hope you are happy with the sound you have. 85db? have you ever been on a concert?


They’re used on a 4ohm load rated into 150watts so I should be safe with an 85db level of around 5watts at listening distance. If I push harder yes they’d be almost running on empty.

I’m going to revamp the amps sometime next year for control 1 and 5 with Behringer A500 for each LCR and later extra front channels, as well as for each stack of surrounds.

For the diy subs I’m looking at Behringer EP2000 which would be way than more than adequate.


http://www.youtube.com/watch?v=_BRv9wGf5pk
If it makes you feel I’ve got light sound reinforcement power! :D

This track jams okay on the control series with some sub bass extension and I’m not grumbling if the lows can reach, (if I wanted it so) 110dbc 115dbc bat that would be too damn loud and I’ve had the SPL db metre reading 126dbc once, no thanks once was enough.
:xmas::tree:

[JBL 4645]

Again: you have no idea what you are talking about. HI-Fi is for people who like music, and good sound. Do you even know what Hi-Fi means? It means "to get as close as possible to the real thing". Your equipment doesn't even are close to this, but I hope you are happy with the sound you have. 85db? have you ever been on a concert?

I don’t like PA concerts they suck because their TOO DAMN LOUD! It leads to hearing loss and I won’t go with 100 feet of one without ear plugs!

And Hi-Fi last time I checked means High Fidelity Hi-Fi for short. I’m glad you’re happy with those JBL 43?? and everyone else, please by all means knock yourselves out.

Have you even tried 85db its a damn site far lot comfortable than ear bashing 100db :D and you know the repercussions from hearing loss when played loud many times, over the years.
:happyh::tree:

[Wayne]

Well the topic mentioned amps of different class Where one amp is going positive and the other negative?

Hi JBL 4645

The Amp your referring to is called a Push Pull Amplifier, it has to utilise 2 output transistors for each channel one amplifying the positive going signal & the other amplifying the negative going signal, it then uses a smaller transistor to stich the two back together before going to your speakers.

These are most common due to being very cost effective as opposed to a class A Amplifier which amplifies the whole signal through one transistor not two, requiring a much larger one along with larger heatsinks, power supply's etc. :blah:

Hope that helps explain a little. :crying:

Cheers wayne
:cheers:

[JBL 4645]

Hi JBL 4645

The Amp your referring to is called a Push Pull Amplifier, it has to utilise 2 output transistors for each channel one amplifying the positive going signal & the other amplifying the negative going signal, it then uses a smaller transistor to stich the two back together before going to your speakers.

These are most common due to being very cost effective as opposed to a class A Amplifier which amplifies the whole signal through one transistor not two, requiring a much larger one along with larger heatsinks, power supply's etc. :blah:

Hope that helps explain a little. :crying:

Cheers wayne
:cheers:
Wayne
Yeah kinder helps so the RA300 that I use have moderate size heat sinks on each side, what type is the Alesis RA300 I only buy them and wire them up and it breaks it breaks I’d send off for repair.

The Marantz1030/50 has a single heat sink in each amplifier.

So how fast how many milliseconds are these two (push and pull) circuits working? I guessing really fast?
:xmas::tree:

[Wayne]

Wayne
Yeah kinder helps so the RA300 that I use have moderate size heat sinks on each side, what type is the Alesis RA300 I only buy them and wire them up and it breaks it breaks I’d send off for repair.

The Marantz1030/50 has a single heat sink in each amplifier.

So how fast how many milliseconds are these two (push and pull) circuits working? I guessing really fast?
:xmas::tree:

The Alesis is a Push Pull Amp, being more powerfull than the Marantz it has to use larger Output Transistors & larger Heatsinks whereas the Marantz can handle the heat dissipated from its output transistors with just the one heatsink, its all about cost. ;)

Dont know how fast this all happens, never really crossed my mind. :blink:

Cheers wayne.
:cheers:

[JBL 4645]

The Alesis is a Push Pull Amp, being more powerfull than the Marantz it has to use larger Output Transistors & larger Heatsinks whereas the Marantz can handle the heat dissipated from its output transistors with just the one heatsink, its all about cost. ;)

Dont know how fast this all happens, never really crossed my mind. :blink:

Cheers wayne.
:cheers:
Wayne
Oh, cheers for that information that was most usual.
:xmas::window:

[Wayne]

Wayne
Oh, cheers for that information that was most usual.
:xmas::window:

Sorry bout my info being most usual, :p guess that comes when one becomes full of the obvious. ;)

Cheers wayne.
:cheers:

[JBL 4645]

Sorry bout my info being most usual, :p guess that comes when one becomes full of the obvious. ;)

Cheers wayne.
:cheers:

Well if you know, you know that’s good enough information for me. But looks like they’re gonna need a bigger boat!:D

Not many days to christmas. So how's the weather in Oz?
:xmas::window: