Need Urgent Help Plz!! RMS and Peak Amplifier/speaker ratings?

[mandeep]

I have recently purchased an old Yamaha reciever DSP-AZ1 which have a ''Minimum RMS rating per channel of 130W''

Now i have Yamaha 8900 Floorstanding speakers with Nominal Input power 80W and maximum input power 300W and i have rear Bipole speakers Wharfedale WH-2, with maximum rated RMS input power of 120W.

My BIG question is, are my speaker's safe with this amplifier having ''Minimum RMS rating per channel of 130W''

Its kind of urgent PLZ Help!!

Thanks in advance

 

[tuff]

Don't worry about it. Go ahead plug it in. Enjoy.

 

[raghupb]

Keep the volume low, as in less than 50%. Get a sub.
Cheers,
Raghu

 

[tuff]

The receiver is rated 130 watts per channel.
Yamaha 8900 can handle up to 300 watts.

 

[mandeep]

The receiver is rated 130 watts per channel.
Yamaha 8900 can handle up to 300 watts.

There is an article online here

It says ''Using an amplifier with twice the power rating of the speaker (or more) is inviting a trip to the repair shop''

and the writer of this article disagree with this article which says '' Generally you should pick an amplifier that can deliver power equal to twice the speakers program/continuous power rating ''

Going by this My speakers nominal RMS ratings are just fine i think

My floorstanders have 80W RMS rating so twice = 80x2 =160 W
and Surrounds have 120W RMS rating so twice = 120W x2= 240 Watt

Note: I am a little unsure about the ratings of my surround speakers though, could not find them on whafedale site. Had to rely on other info on websites.

 

[mandeep]

Another article here says''

Rule of Thumb
For a rule of thumb the best answer is found using what is commonly called the loudspeakers RMS (root mean square) power rating. Use an amplifier that is twice the RMS rating. If you cant find an amplifier with that exact rating, multiply this power rating by 0.8 and also by 1.25 to find a range of acceptable power.

Example: A loudspeaker has a 250-watt RMS rating. Twice this is 500 watts. Therefore the acceptable range for the power amplifier to use is from 400 watts (0.8 x 500) to 625 watts (1.25 x 500). Anything larger is potentially excessive power. Anything smaller can cause damage from the amplifier clipping. Remember that the power amplifier output you select must be rated for the nominal impedance of the loudspeaker (i.e., 16, 8, 4 or 2 Ohms).

The RMS rating represents the thermal power limit for the loudspeaker. It is also a good number to use for comparing products. Twice the RMS rating represents a realistic scenario for most actual audio signals. This is 3 dB more power than the RMS rating. An amplifiers RMS rating is based on a sine wave measurement. The peak power in a sine wave is 3 dB more than the RMS power. Therefore using twice the RMS power rating for the loudspeaker provides 6 dB more power for short term power peaks.

A good loudspeaker can easily handle this. Why? The RMS rating for professional loudspeakers is almost always measured using pink noise for a test signal. The content of this test signal is an RMS level with peaks that are 6 dB above the RMS level. Thus testing a loudspeaker with pink noise requires an amplifier that can produce power peaks of 6 dB above RMS level of the input signal to the loudspeaker without clipping. The rule of thumb provides an amplifier with this capability.''

Could not understand the testing with pink noise part!!!

 

[mandeep]

Reputed site says here ''On the opposite side of this issue are such notable engineers like Ken Kantor of AR and NHT fame. They dismiss this theory entirely, saying that pure high levels of powereven so-called clean power are the primary danger to speakers. Excessive heat is excessive heat, whether its delivered by a distorted or undistorted signal, and excessive heat is what burns out a tweeters fragile voice coil.''

Now i am confused??

 

[raghupb]

mandeep,

Here is the reasoning behind why you are still OK with your system. Amp and speaker rating are always max ratings.
DSP-AZ1 which have a ''Minimum RMS rating per channel of 130W'' is probably a horrible typo.
No amp will power up and start belting out power in watts.

There are 3 primary factors in amp-speaker match up, voltage, resistance, current. All of this is summed up by Ohm's law (V=I*R or I = V/R)
An amp's function is to take a small voltage signal and amplify it to a larger voltage signal (predetermined by gain of the amp).
The volume control is the one that determines the small voltage part.
Amp presents this large voltage signal to the speaker, which in turn presents an impedance or in simpler terms resistance.
To maintain this amplified voltage at a given resistance, the power supply in the amp must supply sufficient current (I = V/R)
If it cannot supply the current, the voltage will be clipped, hence the term clipping (most of the time sound distortion is due to this).
Trust me, you will never be able to drive the amp-speaker to clipping levels unless you go temporarily or permanently deaf.
Here is why.

Lets talk about another spec of the speaker, sensitivity. This is stated as xx dB SPL (sound pressure level)
Meaning a speaker will put out xx dB of sound at a distance of 1 m with a voltage of 2.83V at a nominal impedance of 8 ohm.
This also means 1W of power will produce xx dB at 1 m distance.
The 8900 is an 89dB SPL speaker. WH-2 is an 88 dB SPL speaker.

Say you are at a distance of about 2-3 m from the front and surround speakers. Say you need about 90 dB of SPL to enjoy a movie at listening position.
Mind you it is very high; constant exposure to such levels can cause deafness (temporary and/or permanent).
Both the 8900s and WH-2s need only a few watts to reach this SPL. Roughly 10-20 watts.
Even if there are demanding passages in the movie sound track you are in need of a 3dB boost. About 30-40W of power.

See all is well within safe operating range of the equipment you own, except one, your ears.
So keep the volume reasonable and get a sub to share the load of LFE in a soundtrack. The rest will fall in place.

FYI, I drive 120W (max) rated speakers from 200W (max) rated amp. No harm no foul as long as I don't crank it up.
If I do, my ears and definitely my neighbors will complain before the equipment does.
Enjoy and cherish your setup!!

Cheers,
Raghu

 

[mandeep]

mandeep,

Here is the reasoning behind why you are still OK with your system. Amp and speaker rating are always max ratings.
DSP-AZ1 which have a ''Minimum RMS rating per channel of 130W'' is probably a horrible typo.
No amp will power up and start belting out power in watts.

There are 3 primary factors in amp-speaker match up, voltage, resistance, current. All of this is summed up by Ohm's law (V=I*R or I = V/R)
An amp's function is to take a small voltage signal and amplify it to a larger voltage signal (predetermined by gain of the amp).
The volume control is the one that determines the small voltage part.
Amp presents this large voltage signal to the speaker, which in turn presents an impedance or in simpler terms resistance.
To maintain this amplified voltage at a given resistance, the power supply in the amp must supply sufficient current (I = V/R)
If it cannot supply the current, the voltage will be clipped, hence the term clipping (most of the time sound distortion is due to this).
Trust me, you will never be able to drive the amp-speaker to clipping levels unless you go temporarily or permanently deaf.
Here is why.

Lets talk about another spec of the speaker, sensitivity. This is stated as xx dB SPL (sound pressure level)
Meaning a speaker will put out xx dB of sound at a distance of 1 m with a voltage of 2.83V at a nominal impedance of 8 ohm.
This also means 1W of power will produce xx dB at 1 m distance.
The 8900 is an 89dB SPL speaker. WH-2 is an 88 dB SPL speaker.

Say you are at a distance of about 2-3 m from the front and surround speakers. Say you need about 90 dB of SPL to enjoy a movie at listening position.
Mind you it is very high; constant exposure to such levels can cause deafness (temporary and/or permanent).
Both the 8900s and WH-2s need only a few watts to reach this SPL. Roughly 10-20 watts.
Even if there are demanding passages in the movie sound track you are in need of a 3dB boost. About 30-40W of power.

See all is well within safe operating range of the equipment you own, except one, your ears.
So keep the volume reasonable and get a sub to share the load of LFE in a soundtrack. The rest will fall in place.

FYI, I drive 120W (max) rated speakers from 200W (max) rated amp. No harm no foul as long as I don't crank it up.
If I do, my ears and definitely my neighbors will complain before the equipment does.
Enjoy and cherish your setup!!

Cheers,
Raghu

Thanks for this great explanation dear, really appreciate your effort put into this post.:clapping:
So, the Key is to ''Keep the volume down for a more powered Amp''.