[_scotty_]

As an interested outsider I wonder if it would be possible for Wayne and Turk to
set up both speaker systems to measure as flatly as possible at the listening position before the start of the listening session. Also if a subwoofer is used to augment the Alphas output in the last octave, could the result of their combined responses at the listening postion be measured. The positions of each loudspeakers location and orientation which produced the flatest response could be be outlined on the floor with blue masking tape for
ease in repositioning them correctly when switching loudspeakers during
the listening session. It would also be helpful if the nature of the response curves generated could be withheld from the participants until after their reactions to the listening session were recorded. I realize that I may be making more work for Turk and Wayne,but a methodology like this is would be helpful in quantifying the differences that exist between the two loudspeakers under test. Information gathered in this fashion would be very useful to prospective buyers of either speaker system.
I am looking forward to reading the results from the second listening session. Scotty

[Brian Cheney]

Sorry, this won't work.

If you set up a speaker to measure as flat as possible at the listening position an adjustable speaker like the RM40 will often be unlistenable.  The ear is not accustomed to flat trebles and bass measurements in-room vary inch-by-inch as you move the mic.  Plus, boosting a single frequency boosts its overtones by a like amount.  EQ and corrections of various sorts are called "pushing on jello" by sound engineers I know.

Better to set up each speaker to sound its best in the room, then make measurements as an incidental. And don't rely on them to tell you much.

Note Wayne's measurement for the RM40 shows 10Hz down zero dB at the listening position.  Laughable.

I have on occasion invited manufactures of digital room/speaker equipment into my soundroom and they invariably arrive at measurements (using very good mics and equipment) that is flat to 1dB 20Hz to 20kHz where I sit.  Result: flat, harsh, unlistenable sound with no bass. Mics do not hear the way we do.

[_scotty_]

Brian, my mistake,where do you start the dail in process with the RM-40's.
I assumed that it would be desirable to level match the midrange to the bass output after it was made as flat as the room would allow and then
level match the tweeter. Would it be better to level match the tweeter with the midrange at 1meter so that the the room absorption characteristics
in the HF region would factor into the final response curve at the listening position. I am kind of lost as to how to minimise the speaker/room editorial contribution to what the artist might have originally intended we hear when listening to their recording. Your guidelines on this would be
appreciated. Scotty

[Rick Craig]

Sorry, this won't work.

If you set up a speaker to measure as flat as possible at the listening position an adjustable speaker like the RM40 will often be unlistenable.  The ear is not accustomed to flat trebles and bass measurements in-room vary inch-by-inch as you move the mic.  Plus, boosting a single frequency boosts its overtones by a like amount.  EQ and corrections of various sorts are called "pushing on jello" by sound engineers I know.

Better to set up each speaker to sound its best in the ro ...

I beg to differ. The in-room responses of my arrays are very flat and they sound very neutral. I do agree that simply sticking a microphone at the listening position really doesn't cut it. You have to measure at various angles both vertical and horizontal to get a good picture of what's going on. The NRC studies from the AES verify this.

Rick

[Brian Cheney]

My official position is that in-room measurements are worse than useless, being downright misleading.  However, if you like them who am I to argue?

[_scotty_]

Before the interjection by Mr. Craig, I was hoping Brian would outline his standard dial-in procedure for RM-40s. Thank you, Scotty

[Turk]

I have tried bass treatments in a number of rooms over the years.  

Measurements indicated only small changes, however, the subjective effect was great.  

Also I agree with BC on the room creating small zones of increasing or decreasing pressure with inches of head movement.  So you can measure away to get an overall sense of what the room and speaker are doing and then what?

Scientific design and testing are important but certainly do not give an absolute picture of how any given speaker will react in a given room.

If there was a silver bullet for speaker design and room interface, tell me why speaker placement software often takes hours to calculate?

Why do certain companies charge tens of thousands of dollars to give you the "perfect" room/speaker response?

If it is such simple science why not a calculator and 5 minutes?

Give me a person with great hearing who knows live music and I'll take my chances and never touch a mic.

[Danny Richie]

Wow!

With interest I have looked in on the Denver group to see well educated guys, playing, learning and having a good time with this.

Clearly they have noted and will note room response issues that have been confirmed with measurements that will assist them in obtaining a more accurate and enjoyable listening experience.

Some how I don't see any of these guys being made to believe that achieving an accurate amplitude response is going to result in an unlistenable system.

I have to agree with Mr Craig on this one.

Clearly a room response can be very accurate with regard to amplitude and still not sound very well, as other issues are at play like time delays of reflections, phase issues, driver dissipation speed, and a whole list of other variables.

But even if all else is great, if the amplitude response is all over the place you will not have accuracy and it will not sound as intended or as recorded.

Amplitude variations are of the easiest to problems to detect too.

I also agree with Rick that you can't get the whole picture by measuring in just one spot.

There are a lot of variables that make up the response measurement and what you get in one spot is a sum of everything as a whole.

A speaker may have a dip in the on axis response that is summed flat (in amplitude) by a peaked area in the off axis response, but that peaked area in the off axis will arrive with a slight time delay from the on axis and cause a slight smeared effect.

Room responses can reveal a peak in, say a 2kHz area, that might be stressing some sibilant characteristics. If measurements reveal it as a side wall reflection issue then it can be attenuated with room treatment that will essentially eat up output in that area, that will not only attenuate the output level, but do away with a late time arrival that was causing the smeared effect and the sibilance.

This is where digital room correction misses the boat, just as Brian noted.

Digital room correction with attenuate the output of the speaker in the 2kHz area to equal a summed flat response, but the late time arrival from the side wall is still there.

Now digital room correction in low frequency ranges is very useful and has little ill effect as low frequency wavelengths are very long and slight millisecond delays are undetectable when listening to wavelengths that are in the 56' to 20' long range.

If an accurate (or flat) response is undesirable then maybe someone could show us a response curve of what will sound good and the rest of us can adjust all our speakers accordingly, or maybe recording engineers can make those adjustments for us, maybe the musicians aren't playing it right either?  

Hmmmmm.....

[ctviggen]

There's actually quite a large amount of information about VMPS set up on the VMPS portion of this site.  I assume the same would be true for the Alphas.  

As for the measured response with bass output at 10 Hz for the RM40s, I think the VMPS larger sub was on.  That's why there was 10Hz.  

It should also be noted for both speakers that whoever sets them up is going to color the sound to their liking, anyway (and this is especially true for the RM40s, which allow you to adjust the sound).  If the person setting them up likes "bright" speakers, that's what you're likely to get.  What I would do is have someone set up both speakers to his/her liking at one location in the room.  Use a variety of positions to dial in the best position for each set of speakers.   Search the VMPS portion of the site for info. on how to set up these speakers.  Then, let people listen.  If possible, the only thing that should change would be the speakers (ideally, carrying out the non-used speakers or at least putting them in marked positions).  The only fly in the ointment is the sub -- do you leave it on or turn it off?  Since I don't like subs for music, I'd turn it off, but that's me.

[ctviggen]

I think what Brian was saying is that it's hard to dial in an RM40 to correct for room interaction.  You'd like a perfectly flat response at your seat, but that response is both the speaker and the room (and all its many variables).  What this means is that your speaker might measure flat (in an anechoic chamber or outside with no reflections), but you stick the speaker in a room, and the response will no longer be flat.  With VMPS, you can adjust them to some degree, but the adjustments are there to get the speaker to sound good to you in this environment.  But if you try to do more than this, you may make the sound worse.  For instance, the curves showed (if I remember correctly) a -10dB decrease at high frequencies.  If you turn up the mids/tweeter to try to correct this, you're likely to overdrive the tweeter.  Even if you didn't overdrive the tweeter, you're likely to up the mids, too, which means that the sound could get worse and not better.

[Turk]

Danny

I too agree with the science of design, I stated as much.  You also commented that my Alphas don't sound sibilant because you design your speakers to measure as flat as possible AND YOUR EARS TELL YOU THEY SOUND THAT WAY AT YOUR PLACE. I agree with that statment far more on the basis of your listening than your measurements.  

I also note that your room is treated and you have measured the in room response.  Which do you trust?  A graph that gives you accoustical information or your ears?  My guess is when push comes to shove your ears win out.  So too, with various response curves taken under certain conditions.

If you wish to respond to the practicality of the average purchaser of you product having the wherewithall to acquire, and successfully use the measuring devices and software you and Rick talk about, that is a very small number.  

The reality is that your customers have to deal with crappy rooms, great rooms and everything in between.

So there is no dissagreement from my position on speaker response design.  It is the practicality of measuring once the speaker is in the home,  treating the room and listening to get the best sound.

All of which are variables outside your control as a manufacturer.  So I gather that you and Rick have issues with speakers that either don't measure well or the manufactuer does not reveal meaurements.  

Neither of which in any way addresses my comments on the challenges the average purchaser faces in making even the best speaker soud good.

Jerry








I sense your comments are aimed at

[Danny Richie]

You also commented that my Alphas don't sound sibilant because you design your speakers to measure as flat as possible AND YOUR EARS TELL YOU THEY SOUND THAT WAY AT YOUR PLACE. I agree with that statment far more on the basis of your listening than your measurements.

As to Sibilance, there are many things that can cause it. A residual resonance of a driver that can be seen in a spectral decay, caps that are not burned in, whether in the speakers or in electronics, some electronics cause it, room reflections can cause emphases in that area, a speaker could even have added output in that area.

From my experience with the Alphas I will say that it is not a result of the speaker.

And, sibilance is not something that shows up easily in a measurement unless it is amplitude related.

Which do you trust? A graph that gives you accoustical information or your ears? My guess is when push comes to shove your ears win out. So too, with various response curves taken under certain conditions.

When it comes to whether something sounds good or not, my ears tell me the complete story.

But measurement tools are very useful in pin pointing a problem if there is one.

Say that is a brightness or peak in a given area and you clearly hear it.

Measuring it can tell you if the peaked area is a result of the speakers output or if it is a result of a nearby wall reflection.

These are great tools to have and you guys are fortunate to have these tools available. Most do not.

Our customers must rely on us, that we have given them a product that is free of amplitude response errors (or any other problems) so that they only have the room as a variable to contend with.

Most people can dial them in very effectively using their ears.

So I gather that you and Rick have issues with speakers that either don't measure well or the manufactuer does not reveal meaurements.

It is true that any speaker with measured response problems is going to carry those same problems into the room response. The room will not correct problems.

And if a speaker manufacturer can tell their customers to "trust us, our speakers measure great" but never provide anything to support that, and their customers are okay with that, then it doesn't bother me.

What Rick and I both had issue with was comments that, or the very notion that, if a speaker measures to have a flat in room response that it would be unlistenable, or that a flat response would be undesirable.  

[Brian Cheney]

You can certainly influence in-room response with corrections, which in my opinion are most successful in the bass.  A bothersome room mode can be tempered quite a bit with EQ.  However, placement and (in the case of the RM40) PR tuning can help just about as much.

Measurements above 200Hz should be conducted in a completely anechoic environment to be worthwhile.  The largest anechoic chamber in the country to my knowledge is a cube about 22ft per side, which is not large enough for accurate bass measurements.

A well-treated room is a necessity for getting the most out of any system.

[Turk]

Ok, now the bullshit meter just went off.  Danny, in one post you comment that the DAM can't be so gullible as to buy into the flat  response is irrelevent camp and then follow it in another post with "but hey it's ok with me if people want  to be stupid", then wag your finger

Find a target  and pull the trigger.  Erecting a strawman, making a condescending remark and then pontificating does not a class act make.  

You and Brian have disagreements.  Fine.  My comments went to the difficulty once the speaker gets home and yours deals with the speaker before it leaves the warehouse.  I don't appreciate being used as a means to further your position whether I agree with it or not, when it is not the subject of my comment

     

[_scotty_]

Turk,I apologize for starting this thread, I was only interested in the setup
procedures recommended by each manufacturer to the end user.
What a response curve may tell you after postioning and or adjusting the loudspeaker is interesting but not entirely germane to the discussion.
I was wondering what the end user can do to minimise inaccuracies in reproduction when using these two brands of loudspeakers. I was hoping to hear from Brian without side issues being raised.
 Perhaps you can detail what you have done with each speaker setup to assure yourself of the most accurate reproduction possible from them.
                       Thank-you, Scotty

[Danny Richie]

Ok, now the bullshit meter just went off. Danny, in one post you comment that the DAM can't be so gullible as to buy into the flat response is irrelevent camp and then follow it in another post with "but hey it's ok with me if people want to be stupid", then wag your finger

I said what? Who was not gullible?

The only finger waving in my post was in response to why Rick and I disagreed with a statement made by Brian regarding speaker response not being relevant.

Hey you guys are the ones taking measurements. Did it help in setting them up or not? It looks to me as if it has.

[Brian Cheney]

Measuring response in room at the listening position is indeed chancy, and often misleading.  I don't favor it above 200Hz.  Move your mic a few inches and watch what happens.

I am all in favor of nearfield measurements of each section, which will let you know what the drivers are doing.  By nearfield I mean close enough for the mic to almost touch the diaphragm.  This method says nothing about system response but lets you zero in on a problem source such as sibilance.