Discussion on loudspeaker measurements as they relate - or don't - to sound

[English210]

For a simple way to get an idea of what your room is doing you would take quasi-anechoic measurements of the L/R. Then take LP measurements of both the L/R and average them. I like to take another one with both playing at once as well. You may also want to do this across the listening positions for both speakers. This will at least begin to give you an idea of what the room is doing to the FR response of the speakers. There's a lot more to it than that, especially since you may not be listening to your speakers on axis, but this is a start. Plus if you take REW measurements you can send the mdat files to someone else who has REW and they can get a little more from the measurements since REW doesn't just take the FR response when you take a measurement.

If you choose to invest in a USB mic and REW (which really means just a USB mic) you can send your measurement files to someone else who has REW and they can interpret them for you. All you need to do is make sure your measurement techniques are solid.

Wow, I really don't know anything...
Quasi-anechoic measurements?
LP? Low Pass? As in how low the mains can go?
USB mic? As in a mic that plugs into the USB port on the computer and feeds the REW program?

 

[fuzz092888]

Wow, I really don't know anything...

Hey, ya never really know until ya know. Ya know?

Quasi-anechoic measurements?

An anechoic chamber adds nor subtracts anything from the speakers. It's a totally dead environment. A way to get around that is by taking your measurements from 1 meter away, controlling how long the mic is "listening" and not taking a full range measurement. You take from 300-20K and then do the bass measurement separately. This will get you pretty close to what the speaker will measure in an anechoic chamber IE without any room stuff influencing the measurement.

LP? Low Pass? As in how low the mains can go?

LP = listening position in this context.

USB mic? As in a mic that plugs into the USB port on the computer and feeds the REW program?

Yes. Far simpler than traditional mics that require external soundcards and tons of setup, which was what traditionally made REW difficult to use. Now for ~$100, you can have a setup that does nearly everything the omnimic system does for 1/3 of the cost.

 

[English210]

Ok, so I need the REW program and a USB microphone, and some patience? No need for soundcards, or other things I've read about over there?

Quasi-anechoic measurements at the speaker, and then LP measurements, the difference between the readings being what the room adds/subtracts?

(thanks for your patience with this, I seem to hit overload quickly when reading articles about this stuff, it's only just now making any sense)

 

[fuzz092888]

Ok, so I need the REW program and a USB microphone, and some patience? No need for soundcards, or other things I've read about over there?

Quasi-anechoic measurements at the speaker, and then LP measurements, the difference between the readings being what the room adds/subtracts?

(thanks for your patience with this, I seem to hit overload quickly when reading articles about this stuff, it's only just now making any sense)

Correct. You do have to calibrate your computers soundcard but all that is covered in REW setup or I/others can help. I recommend buying a mic from Cross spectrum labs because they independently calibrate the mics for about equal money to what you would spend anyways.

Sort of, it will differ from spot to spot, especially if your room has any nulls. REW can help you calculate room modes and other stuff as well which will also help you with placement and calibration. Once you take your LP measurements you'll also be able to see if any frequencies are ringing or doing anything weird.

No problem, it's a lot to take in when you first start. We've all been there.

 

[JerryLove]

Fuzz has already torn into details, and I'll leave him to it; but to answer the question "yes".

How a speaker will sound in a room is a product of the speaker itself and its interaction with the room. To convert measurements into performance, you would need to know how to apply the effects of the environment to what you are reading.

One mistake often made is to look at something as simplistic as a FR chart as though it can tell you a speaker is good. It cannot. It can tell you a speaker is bad, but not good. You need a lot more information than that single metric (waterfall plots are a bit more useful, but still far from complete). You also need the knowledge to relate objective data to subjective experience to determine the importance (both relative and absolute) of a given imperfection.

On top of this, you need to understand the environment the speaker will be in (the room) and the personal expectations of the listener.

 

[twylight]

The whole thing a little more complicated than just the speakers as many people have pointed out.

room (dimensions, seat placement)
+ reflections (what is hitting your ear in the seat)
+ speakers (duh)
+ placement (in relation to walls, seat, and toe in)
+ recording quality (poor recordings and terrible compression become obvious detractors)
= measurable sound


(notice I left off amps, cables, dacs, tubes, and other items in measurable response)

A "flat" speaker doesnt have an impact on all those other things...a V shaped curve or other alteration (bass heavy, treble roll off whatever) amplifies all the other imperfections of a listening room.

I vote to spend a little more in all measurable areas, get a sub juice it a little hot, and have some fun. The worst is seeing a 20-40k pair of speakers in a square, tiled room with bare walls and the "forever alone" chair...or at least "married and this is my room chair" in some cases.

As a interesting note : Audyssey default mode is not flat...

https://audyssey.zendesk.com/entries/94162-MultEQ-Target-Curves

BTW the audyssey guy explains a lot of concepts REALLY well and is worth reading

PS Have your hearing testing...you probably cant hear squat above 12-14khz if you can afford super nice stuff in life as a normal wage earner

 

[JerryLove]

As a interesting note : Audyssey default mode is not flat...

https://audyssey.zendesk.com/entries/94162-MultEQ-Target-Curves

BTW the audyssey guy explains a lot of concepts REALLY well and is worth reading

That guy espouses a position which I find logically incongruant (and I'm drawing a great deal from a separate audessy discussion by him). Let me explain why.

I will assume, for the sake of argument, that somehow an inaccurate reproduction (one with the exact curve he describes) is sonically superior for listeners than an accurate reproduction.

Most music is produced. The mixing engineer will adjust for his preferred sound. So he will put that dip in and then audessy will double it.
Any speaker manufacturer who is not aiming at flat , and that's many (hi there Bose), will also put that dip in, so now we are triple-dipping.

Now it's possible that audessy is going for the end result of a given curve based on sweeps. In that case, we can remove the speaker portion of the discussion (the ideal would *still* be a flat speaker so that audessy can unflatten it.

As to the HF roll-off, again it's the wrong place. To get ideal results requires that the sound engineer on the movie create a non-ideal source so that, once modified by audessy, it becomes ideal. It's a silly idea at best.

There are two places to determine what something should sound like. The first is in the *production* stage, and the second is in user preferences. That audessy is doing something other than room/position compensation by default is, bluntly , bad.

I suppose this explains why I usually prefer audessy off.

PS Have your hearing testing...you probably cant hear squat above 12-14khz if you can afford super nice stuff in life as a normal wage earne

Yea. My conscious hearing peters out (at low volume) around 14khz these days.

 

[Swerd]

I suppose this explains why I usually prefer audessy off.

There seem to be many Salk owners who agree with you.

Typical comments from them can be summarized as "audessy sucked the life out of my speakers sound, so I switched it off".

 

[fuzz092888]

There seem to be many Salk owners who agree with you.

Typical comments from them can be summarized as "audessy sucked the life out of my speakers sound, so I switched it off".

And philharmonic owners minus ADTG

 

[English210]

And philharmonic owners minus ADTG

Cue response from ADTG??

So, the plan is to use a mic and REW (like the calibrated mic you suggested at $95.00 plus shipping) to determine my in room response as-is, then use the parametric EQ in the AVR to dial out the rooms modes? Or does REW allow me to load a curve that will correct the rooms anomalies?

 

[English210]

Isn't it presumptive to assume the recording engineer assigns the same curve as Audyssey? I can see them going by their preference, but how do we know their preference is the same as Audyssey's. I know nothing about that side of the process, so maybe I'm being presumptive, but it seems to be an big assumption..?

 

[fuzz092888]

Cue response from ADTG??

So, the plan is to use a mic and REW (like the calibrated mic you suggested at $95.00 plus shipping) to determine my in room response as-is, then use the parametric EQ in the AVR to dial out the rooms modes? Or does REW allow me to load a curve that will correct the rooms anomalies?

If your AVR allows you to set that stuff than you can. REW is able to send customized EQ but only to certain devices and you usually need to be run in external amps as well because the miniDSP fits in between the receiver and amplifiers.

A mic and REW can help you understand your room, optimize placement, and help determine what characteristics in a speaker you like and don't like without the miniDSP or other DSP EQ stuff.

 

[tracieisz]

I think are some of their best features.

 

[JerryLove]

Isn't it presumptive to assume the recording engineer assigns the same curve as Audyssey? I can see them going by their preference, but how do we know their preference is the same as Audyssey's. I know nothing about that side of the process, so maybe I'm being presumptive, but it seems to be an big assumption..?

Inherent in audessy's claim when they force this on all users is that this is "better" for at least the vast majority of ears.

One must then assume that this obvious truth has been missed by the rest of the recording industry in total, or they would have made these adjustments on the masters long ago.

What is presumptive is their conclusion that an unknown speaker will have a given set of characteristics.

See: https://audyssey.zendesk.com/entries/410117-Midrange-Compensation

"Our findings showed that the dip in the 2 kHz range is desirable regardless of the exact xover frequency of your speaker. "

The even reference a century-old story of the "BBC dip" indicating that this isn't new.

So if a dip around 2khz is preferred, and this has been known in the industry for nearly a century, wouldn't at least some mixers deliberately (or by trial and error) put in in the mix? Audessy is taking away my choice by imposing EQ I didn't ask for.