what does the spec 2ch drive mean?

jruder

This is probably a newb sounding question but the marantz SR6013/SR6014 9 channel receiver states the following:
Featuring discrete high-current power amplifiers on all channels, the SR6014 delivers 110W of power per channel (8 Ohm, 20 Hz - 20 kHz, 0.08% 2ch drive).

What is that saying?

Thank you!

tratliff

110 watts per channel when only two channels are driven. As each additional channel is driven the power per channel is significantly reduced.

DaveHo

That means it will deliver that amount of power with only 2 channels of the receiver (Front left/right) in use. In other words, with all channels being used, it will deliver much less than it's rated power.

jruder

Thank you...

Would that not be an extremely useful spec to know?
What is the power with all channels driven?

I am assuming this is being limited by the amount of current the PS can supply to the amplifier circuits?

mhardy6647

jruder wrote: »

Thank you...

Would that not be an extremely useful spec to know?
What is the power with all channels driven?

I am assuming this is being limited by the amount of current the PS can supply to the amplifier circuits?

Not really - what matters is whether the amplifiers are capable of delivering the power require by their loads (the loudspeakers) at any given moment -- power being defined as voltage times current. This depends upon the program source (music, movie soundtrack, whatever) and the loudspeaker's characteristics (fundamentally the impedance curve of each loudspeaker as a function of frequency).

The two-channel spec is significant if one is interested in using the receiver (or whatever these Marantz things are) for stereo music. The fundamental amount of power available to all of those individual channels (nine of them?!!?! jeepers...) is limited by the capability of the (single) power supply in the receiver. It's sort of a zero sum game. More power required by, say, L & R front channels means less is available to the other seven.

mhardy6647

A little googling turns up the "specs" in the US for the SR6014 receiver:


source: https://www.us.marantz.com/us/Products/Pages/ProductDetails.aspx?CatId=avreceivers&ProductId=SR6014


So, what is that "70% guarantee", I wondered -- so I looked it up.
Here's what Marantz says:

70% Power Guarantee
Marantz has the 70% power guarantee, meaning that a minimum of 70% of the stereo power indicated in the specification section will be available when 5 channels are simultaneously used. A lot of misunderstanding about power rating has been created by claiming the highest possible output power as a unique selling point. Measurement often has been done on only 1 speaker drive, with lower impedance than 8 ohms and high THD (total harmonic distortion) acceptance. A standard THD value is 0.08%. The lower the better.

source: https://www.us.marantz.com/us/support/pages/glossary.aspx


so, this says (well, strongly implies) that if five of the nine channels is driven, the total power output 'guaranteed' for each of the five channels would be 70% of 110 watts = 77 watts per five channels driven. Nothing is said about frequency bandwidth nor total harmonic distortion for thi\s guarantee -- the wording is ambiguous because it invokes 0.08% THD but only in a statement about typical industry shenanigans of publishing specs for a single channel driven.

Interestingly, the actual manual for the SR6014 makes subtly but clearly different claims (?!):


source: http://manuals.marantz.com/SR6014/NA/EN/

I.e., read closely and don't assume specs mean something they don't tell you!

Fortunately, the specs (i.e., the numbers) are far less meaningful than a "use test" in one's own home, with one's own speakers, etc., etc.


caveat emptor

tonyb

jruder wrote: »

Thank you...

Would that not be an extremely useful spec to know?
What is the power with all channels driven?

I am assuming this is being limited by the amount of current the PS can supply to the amplifier circuits?

Welcome to the art of receiver power ratings, it's not so much what they state, it's what they "don't" state.

jruder

Wow...I really appreciate all of the time that went into that.

Very interesting and eye opening!

Joe