[cosmopragma]

Quote:

Originally Posted by bigshot Get an HP signal generator.

Could you please elaborate a bit?
I hope there's a software version, I have enough boxes standing around here.

 

[clarke68]

Quote:

Originally Posted by Zuglufttier But headphones could be tuned rather easy I think or am I wrong?

Here is a really good page on how to test headphone frequency response (using a frequency sweep) and build a simple equalizer to tune them.

Quote:

Originally Posted by Zuglufttier I'm pretty convinced that it is completely impossible to tune your system in a way that makes all frequencies sound equally loud. Even then your ear still works not linear and a peak in the music signal would mean that the sound might not be right.

The article above mentions that it is impossible to tune a system in a way that everyone will hear all frequencies at the same volume, but you can set it up so you frequency response is flat to you. Also your own hearing my vary even from ear to ear.

Quote:

Originally Posted by Zuglufttier You can really enjoy music even if your setup cost less than 30 dollars

Very true! If you're enjoying music on a $30 system right now, there's some wisdom in quitting while you're ahead.

 

[arnaud]

Quote:

Originally Posted by bigshot If you can hold off till tonight, I'll call my engineer friend who is in the middle of dealing with all of the issues you're talking about. I'll read him your questions and transcribe his answers for you. He's bound to have some interesting things to say. See ya Steve

Steve, maybe you should try to gather some piece of advice from successful loudspeaker manufacturers. Typically, most newbie designs are pure failure simply because the designer focused on making a flat frequency response.

Still, if we remain in your seat and believe it's all about frequency response:
Jazz mentionned the quite complicated dispersion characteristics of a loudspeaker with multiple filtered drivers, while in a typical listening room. If I may suggest you a simple test: repeat one of your FRF measurements, moving the response microphone by a few inches and try to line up the curves... Then may I ask which (non smoothed) curve you'll choose to perform your full frequency equalization?

If you think it's easier with headphones, what about you repeat measurements of a single headphone just very slightly moving its position relative to the head every time. Even more dramatic, make measurements on different heads... You won't find two matching curves.

Second suggestion: as you probably know, frequency response has a magnitude and a phase. So, are you also phase equalizing by any chance? Phase takes a funny meaning for a loudspeaker in a typical room where 50% or more of the sound reaching the listener is due to multiple random reflections of the walls. Or maybe phase response is irrelevant for you?

Finally, if you are still convinced that flat magnitude response is the way to go, have a listen to one of these high end fully digital and parameterized Meridian systems. They did throw a lot of money at the problem AND, as you wish it, their goal was to make a flat response. Well, it sounds good, but clearly not to everybody's taste and clearly not considered world reference system... There's more to audio than frequency response function, you'll have to admit that some day...

Arnaud.

 

[bigshot]

He isn't using a microphone... He's tuning the sytem by ear from a central listening point.

I'm just a dabbler, but this guy could teach a college course in speaker design and theater acoustics... He's been building systems for well over twenty years and has been trying out various combinations of techniques building up to this design. He just told me about a new aspect of the system he hadn't told anyone about yet, even the speaker manufacturer rep he's in contact with. I'm going over to visit him to do some tests with his prototype tomorrow if the weather isn't too hot. It sounds pretty interesting. I don't feel comfortable talking about it until he makes it public. It seems that the bass cabinets are just a part of the story.

But what people don't seem to be understanding is that this isn't a home system. It's a modular PA system that is scalable for anything from a small nightclub to an arena sized venue. The prototype is 1/4 of the complete rig, so it fits in a room. The thing that really sets this system apart is that it is tunable to deal with the acoustics of any setting better than the best PAs out there right now, and it provides as wide and as balanced a frequency response and dynamic range as the best home systems. I know that's a lot to take on in one bite, but this guy is well qualified to be able to pull it off, having been on both the design side and the sound mixing side of PA rigs for decades. I'm sure he'll be heading up a team at one of the major speaker manufacturers very soon to put his designs into production.

See ya
Steve

 

[boodi]

Quote:

Originally Posted by bigshot The things that many audiophiles take for granted, like a flat frequency response, are the things that *count*. Think about it... When a set of speakers is rated to +/- 3db, can you hear what 3db sounds like? Yes. You can hear it, I can hear it, my 85 year old mother can hear it. And +/- 3db is REALLY GOOD SPECS for speakers. If you run a signal through a silver cable and compare the output on the other end to the output of copper zip cord, it isn't going to be anywhere near as great a difference as that. In fact, the frequency response problem is going to be easily several orders of magnitude greater. Next, pull out the specs for your system. Look at the specs for your CD player and amp. Compare those to the specs for your speakers... Again... not even in the same ballpark. Now, look at your room. Is it acoustically perfect? Is the sound that comes out of your speakers exactly the same as the sound you hear in the room? I bet there are very few here who can answer yes to that. What's the point of spending a boatload of money on a sound system only to put it in a room that thows the frequency response off as much as 20db? So, why are people worrying about minute differences in cables and distortion levels in CDs that don't even come close to the levels in their speakers, when they could be spending their energy correcting problems that are clearly audible... with a little bit of simple equalization?

I've always found equalization "cure" the sound results in a good ( not bad ) way .
In my system , equalizing helps to correct the tone of the music .
this is a fact for me , as I use equalizer with the aim of finding out the best "right tone " for different classical instruments - when I've worked out what's the eq. setting in my system ( it takes some day , i do not overfuel with sound my ears and tend to do the operation in days while giving ears the relax they need to stay *bit* more objective ) so I really think equalizing can help .

When i change a gear ( IC , for example ) i re-equalize , but not as a rule , just to find out the best timbre , again .

When I'm set on one eq I've built up through many days of relaxed listening , it lasts as the best eq. (sound) for a long time(ever) , and even if i test it ( trying moving subtly up and down some levers ) I return to the parameters set I've set . If i cut off equalizer , I listen to the system for a time to get accostumed to a new sound again , and to be able to discerne subtilities , thing that's not possible to do in a session only .
Then -again- I spot some flaws I want to correct , and start recalibrating the eq ( in general i tune right tone of instrument through many cd ). End -surprise- I end up with a very close if not the very same eq. set I had before .

So ( my opinion ) ..
is true every system has some colours ,more or less, and equalizing helps to *cure* the overemphasis and bumps ( and micro bumps ! ) of frq.s that results off a particular system gears combination .
..and I see synergy as a combination of colours ( , that eventually may sort out a good sound )

Sorry if I'm repeating again here things I've said yet around .. but waht I think is that when one decide to add a good equalizing system to the chain it's not so easy he's going back to not eq. after hearing the general tailoring (=improvment for me) he can have on the sound

[size=xx-small]and , again (disclaimer ) I admit and want to say that hp-2 helped me a lot doing the fine tuning - before them it was more difficult and more braining to find the " right tone " [/size]

 

[arnaud]

Ok,

I see where you're coming from now. No offense but it is now obvious you have different listening maturity than many of us here. While the art of PA is about making it loud, distortion free and evenly balanced at most seating locations of the crappiest of concert halls (not an easy feat in itself!!), home audio reproduction (at least the high-fidelity portion of the crowd) is a little more than that... For instance, we talk about soundstage, an irrelevant concept for PA designers but crucial design parameter in audio equipment... That's where phase (the second part to frequency response, which you've ignored until now) comes into picture.

It's interesting you now say your friend is tuning his systems by ear, he must have a pretty damn good hearing to end up with a totally flat response +/- 1dB. But lets assume he does. Can you ask him to repeat the process at various volumes levels? (hint: it's gonna become funny again when you find major changes in the equalizer across tests, the so called loudness curves... ;o) ). Or maybe he equalizes like in a PA system (at 110+ dBSPL in the room) where we pretty much all ear the same, right!

Also, not wanting to step on your blind admiration to the PA designer friend, but room equalization for loudspeaker has been done time and time again in the past. I wish he had a revolutionary concept to bring on the table, but I also very much doubt it...

Anyway, I should stop thread crapping now... I just hope you'll open your ears to other people, especially knowledgeable home audio designers...

cheers,
Arnaud.

 

[bigshot]

Phase cancellation is a major issue in PA systems, and his system is designed to eliminate it.

Yes, he can hear differences of +/- 1db with his test tones.

The EQ is tuned at gradually increasing volume levels, and this particular system has no "loudness curve". The balance is the same loud as quiet.

Equalization is an important aspect of any PA installation, but most pink noise based tuning schemes are very inaccurate. My friend has developed a new technique that gets the response much flatter.

When you say "Home audio designers", do you mean the salesmen at your local high end audio store, because that sounds like where you've been getting your information. I'd offer to schedule an audition for you, but I'm in Los Angeles, and it seems that all of the folks who don't seem to be able to wrap their head around this concept are all in Luxembourg or Bavaria or something.

In the meantime, I'll work on "maturing" my ears...

It's amazing how people who are basically clueless can be so convinced of their superiority, and how quick they are to offer opinions that display how little they really know. I guess in the land of the blind, the one eyed man is King.

See ya
Steve

 

[arnaud]

Quote:

Originally Posted by bigshot When you say "Home audio designers", do you mean the salesmen at your local high end audio store, because that sounds like where you've been getting your information.

Yes my friend, I went to Radioshack and got a lecture in structural acoustics from the clerk. It turns out I also:
- have a M.S in acoustics and vibrations
- have done research on active noise control in home environments (my thesis was on active noise control of computer noise)
- have actually worked for an audio manufacturer in France (Cairn), designing loudspeakers (they have stopped designing loudspeakers since, and I was not very successful while there I admit ;o) )
- have for the past 5 years done daily consulting in high frequency vibro-acoustics and thus well versed into room acoustics
- actually give trainings in structural-acoustic to engineers all over the place and thus must have some sort of clue about the problem

Quote:

Originally Posted by bigshot I'd offer to schedule an audition for you, but I'm in Los Angeles, and it seems that all of the folks who don't seem to be able to wrap their head around this concept are all in Luxembourg or Bavaria or something.

It turns out I live less than two hours drive from your place... Provided I can see some politeness and friendliness in your talk (not obvious so far), I would actually be tempted to discover your magic bullet!

Quote:

Originally Posted by bigshot It's amazing how people who are basically clueless can be so convinced of their superiority, and how quick they are to offer opinions that display how little they really know. I guess in the land of the blind, the one eyed man is King.

Well, I shall repeat what Jazz very well said: it's wiser to know that we don't know something... And amazingly, you treat audio the same way you treat people! I can admit I know too little about loudspeaker design (having myself failed the test...), or else I'd be rich by now. But I have somewhat of a hard time being told I am clueless in acoustics, especially coming from somebody like you

.
Arnaud.

 

[bigshot]

I apologize. You came in on the tail end of a very frustrating discussion that went in circles, and I didn't have much patience left. When I'm treated with respect, I reciprocate.

The system is in Burbank. If you'd like to hear it and speak with my friend about his design theories, you're welcome to stop by any time. You can PM me and let me know when would be convenient for you.

Thanks
Steve

 

[arnaud]

Next time I plan a trip to L.A, I'll contact you Steve. I am curious to hear the system you describe and looking forward to discuss it with you and your friend.
cheers, Arnaud.

Quote:

Originally Posted by bigshot I apologize. You came in on the tail end of a very frustrating discussion that went in circles, and I didn't have much patience left. When I'm treated with respect, I reciprocate. The system is in Burbank. If you'd like to hear it and speak with my friend about his design theories, you're welcome to stop by any time. You can PM me and let me know when would be convenient for you. Thanks Steve