Audio theory on "upgrade or expand". - Page 2

Because most subwoofers are self-powered and do not require amplification


I would speculate because 2-channel is very popular, but being popular doesn't make it "right". There are lots of popular trends in audio, most of which are based on myth than sound science. Just read few threads above and below yours and you will get some taste of them.

Substantial as far as smoothness of measured in room response is concerned. Usually significant in terms of output and extension as well. Remember, a fullrange speaker that is "flat" to 30Hz may measure that way at 85dB, but at what output level can it sustain that? Even if you don't listen at loud average levels, you don't want the bass distorting horribly on transients during music or movies. You want lots of clean headroom. You don't run your car full speed day in day out do you?


You'd use an active crossover (probably built into your receiver) and lose all that low end response you paid so dearly for.


Now you've got it! You can run mains fullrange if they are really capable of that (few are), and some like Geddes seem to advocate that (though not with true fullrange mains). But to do this will likely require finesse with EQ, level settings, and perhaps even modifying the mains for use with an active crossover. Not easy... certainly not the easier path.


People prefer all sorts of things that don't always make sense. Can you construct a great sounding fullrange two channel system? Yes. Is it easier to get there with a 2.x system? Yep. Is it easier still to get there with a 5.x/7.x system? Yep, though more costly (ease and cost aren't always the same thing). Can a 5.x/7.x system ultimately achieve a superior performance (more accurate, more enjoyable, more dynamic, however you want to try to quantify it)? I believe so, and many others do as well. But you have to start somewhere. Think in terms of 2.1 where the mains are something you can easily match center and surrounds to later (i.e., don't pick something that either doesn't have a center in that line or has a poorly designed one... best to just use the exact same speaker for the front 3 L/C/R) and a sub that you can afford to add a second or even third later (though this isn't as critical... many advocate having one main sub and a smaller one or two to help smooth response, and this is a reasonable and well proven method). So look at the long term, not necessarily the immediate next step, and then decide which step you want to take first.


Glad we can help.

BTW, the easiest mains to integrate properly with a sub are sealed with a second order roll-off around 80Hz. "THX" style theater speakers follow this philosophy, but you don't have to look for THX certified speakers, and conversely many THX speaker aren't worth a crap anyway.

The next easiest mains to integrate properly have a roll-off around 40-50Hz, whether sealed or ported, in which case you would use a fourth order crossover at 80-100Hz.

Fullrange mains that go down to 30Hz or so are easy to integrate, just a waste of money.

The most difficult are small ported monitors or bookshelf designs that are flat to 60-100Hz or so, as this is close to your final crossover point and in my experience matching a sub to the natural 4th order ported roll-off where group delay is going crazy is difficult to manage well.

Sir, I beleave His Utterly Highness, "König AJ von FLA" is bussy looking for where his pants went (the answer is to look DOWN, as in my signature .

Oh, and BTW, you're not the only one waiting....

bewdiful

Challenge to you:
1) Keep your pants on the next time you are in the jacuzzi with Ing
2) Keep your head above water when he is in front of you explaining why he cherry-picked this irrelevant measurement to hide diffraction. You'll hear better than way.
3) Pick up a high school physics book and learn about diffraction.
Here, I'll show you:





cheers,

AJ

Lucky you.


Yes.


Yes, although much less so, depending on where you place the speakers and sit.


With 95% of music you would not notice much, given your listening habits.
With movies, you would should definitely notice.


Because it's true most of the times, not all.


Yes, but you should still have access to many excellent designs, if not the KEFs. Controlled directional response off axis, etc. is nothing new.
There may be DIY subs/kits etc available as well to keep the budget reasonable.

cheers,

AJ

The order and type of a filter specifies the shape of the filter's response.

All other things being equal, higher order suggests steeper slopes in the transition band. A filter of this kind has three bands - the pass band, the rejection band, and the transition band. The usual ideal is for the pass band to be flat, the rejection band to be very low, and the transition band to be narrow.

In speaker crossovers there is an additional system goal, which is for the merged frequency response of both speakers to sum to be smooth and flat both on-axis and off-axis. Non-flat pass band response and a non-ideal transition band can and have been used to achieve this goal.

What is missing from your sentence is the type of filter, such as Butterworth, elliptical, Bessel, Chebyshev, etc.



80 Hz or less.


Good question. It is fair play to use a speaker down to its lower bandpass if it has good dynamic range and low distortion down to that frequency, which many modern speakers accomplish.

You see the speakers act like filters that add to the filters in the crossover. There are two simple condtions:

(1) The main speaker's lower bandpass is the same as that of the crossover and the two add together in reasonable way to produce a desirable filter characteristic that matches well with the subwoofer.

(2) The main speakers respond well down to a frequency that is significantly lower than the crossover frequency, and therefore this roll-off has little or nor effect on the crossover point. This is hard to achieve because the main speakers would need to go down an octave or more further than the crossover frequency, ideally several octaves (2 octaves below 80 Hz is 20 Hz)

The third case is messy, where the crossover and the speakers both roll off within the same octave and they interact. This is also the usual case. ;-( The good news is that the ear is less discerning at frequencies this low, and the room is probably contributing some issues of its own. This mess may be less significant than other messes that are going on at the same time.



I don't know what you are talking about. I quickly pulled up this reviews of several high quality speakers inccluding some from Paradigm in that price range that went down to 40 Hz in a typical listening room setting. I also found some cheaper alternatives that at least looked good on paper such as the larger members of the Infiinty Primus Series.


Yes.



Your imagination has run away with you. ;-) Crossovers are static, you set them and they stay that way, devices.

I've seen dynamic filters used to control the low end of speakers, which in this case would be your subwoofer. But if you think about matching between the mains and the subs, there is very little advantage to a dynamic filter here.

Rather than hypothetical, why not list some speakers that are available to you in this price range? Loudspeakers are generally specified by anechoic conditions. Room response, including bass/LF extension, will be affected by the space.


Generally speaking, yes. Some amplifiers allow the frequencies (High pass and Low pass) to be set independently. So you could "overlap" by high passing the main speakers at 60hz, but low pass the sub at 80hz. Then there is the subwoofer itself, which will have it's own variable low pass filter (FR) control, phase, level etc. which can also be adjusted. Doing things like this by ear is risky, measurements are preferred. Does your Onkyo have a "room correction"/mic feature?


That's very different from a 25x25 room.
TV & main LR speakers should go on wall 1. Speakers with HF directional control placed >2-3' out from wall 1 and >2' from side walls and toed inwards. Main seat/sofa 8' or so back from speaker plane, so you form somewhat of a 8' (ish) equilateral triangle from speakers to you.

cheers,

AJ

You seem to be drifting quite a bit from your initial post. Some of the replies have been highly technical and are fine, but it all comes down to what you end up with and then listening and you may or may not like it. No amount of explanation via text can really tell you what the speakers will sound like in your acoustical environment.

Yes.


Yes.



Yes.



They were designed to work pretty well without subwoofers.



Exactly. The subwoofer takes a load off the main speakers, regardless.

Without the subwoofer,you;d probably drive your main speakers full range and hope for the best.

With the subwoofer you take a load off the main speakers and also provide better performance at frequencies where the main speakers aren't happy at all.

Ah, at least now I understand why you don't understand. If you had actually read up on the subject before trying to sell in your grossly oversimplified high-school experiments and mickey-mouse models as "evidence" for a phenomenon you *assume* must be severe, when in fact it is not. Allow me to reiterate (again):
http://www.avsforum.com/avs-vb/showt...0#post20639560

It is amusing, or rather, it is a bit tragicomical, that you bash down on this design, when in fact, everything points to that the baffle on your DIY speakers have baffle with a size and edge that is pretty much in the butterzone for edge diffraction problems. Go figure?!?

I haven't seen AJ's speakers. Any information including pics on them?

Then take the 4hr drive to Capital Audiofest (Jul 8-10 weekend). See them with your ears as well .
See if I walk the walk. So easy to play incognito and hide behind computers here eh?
Not I.


cheers,

AJ

p.s. this isn't my first audio show

Wish I could AJ but if you want to throw me some information, I'd appreciate it. Do you sell your product(s) commercially?

I didn't say severe, I said it was most definitely there. I also didn't say what effect it might have on the perceived soundfield either. Try reading my posts for a change.


From your understanding of physics...of course.
BTW, mine really are capable of "125db" per speaker, free space.
And whereas there will be some compression and distortion for sure, it will most certainly not be in the realm of a 8" 2 way DR box speaker.
I'll leave the SPL meter on and let Chu crank 'em when I'm outside the room.

cheers,

AJ

They are about 4' tall.


Nope.

cheers,

AJ

4' huh? Would you say they're optimized for little people?

To exhibit must've cost a few bucks seeing as you're not selling them!

Correct, I beleave you havn't (I hav't bothered searching, like I am sure you will when you see what I say further down this post). Still, you *imply* it, and keep bringing it up like the energizer bunny on crack...

OTOH, had you actually read my very first response, and perhaps asked questions instead of immediatly resorted to your usual modus operandi -putting seemingly endless time and effort into trying (in vain, mind you) to redicule the person, rather than the content, you wouldn't have ended up here, trying to smooth over your false assumptions.


See, I don't say diffraction does not occur or that the phenomenon does not exist -just that it is no technical reason to expect such problem.

For me this rubbish discussion is now over. I have made my point. I suggest you move on with your life as well.

Sure you have Chu!

Not only have you seen his speakers, you have seen his room.



You will struggle to get any technical data about them, presumably to ameliorate the risk of having them examined. He'd much prefer that any mudslinging come from him directed towards others.


Ah well then, so we come back to the important question then, 'what audible difference does it make?'.

You can argue the n'th degree theoretical idea but at the end of the day 'is it audible'.

Wait, this is the wrong thread. You argue that when you are engaged in your imaginary battle with your perceived enemies. Yet you adopt the same thing you rail against when it suits your purpose.

Because you are a hypocrite and a liar.

Anyway, I am calling you on your statement. BS. You have and do say that it is severe, it is (one of) the 'fatal' flaws in the design. Again you are lying.

Now, please be my guest and have the sugarlumps to go on and explain how in MY case the speakers suffer from diffraction problems.

And, using the picture above, conversely how yours have no diffraction problems.


That was just to further illustrate the hypocrisy and unbelievably sickening nature of furbies posts.

'Cheers'!!??

Nothing could be further from the truth, as we would expect.

So what does this sidetrack have to do with the thread? Well, it simply shows where this guy comes from (for those who don't yet know). He is happy to denigrate all and sundry. He THINKS it somehow makes his position stronger because he (thinks) he has managed to put the other down.

So, that type of behaviour needs to be borne in mind when evaluating any 'advice' (note the sig) given by forum furbie.

Always remember it is a cookie cutter approach to audio, one entirely dominated by copious bookmark folder references carefully selected because they back up his already help position.

You want a cookie cutter result?

Follow his advice.

And you too can listen to your system in circumstances approaching a bathroom.

Is that a bottle of hand lotion in the lower right hand corner?

Lol, I had noticed that one too and had the same thought for a second before moving on.

You f'ing kill me, chu, you really do. Just a single, seemingly innocuous question, but squarely aimed at the comedic jugular. "Brevity is the soul of wit", indeed.

Nope. Only for the rooms I put them in (other than Dunny's favorite tiled one). That's why the top coaxial dipole panel rotates independently of the bottom woofer system, which is a dipole and a monopole - each has a separate amp and can be remotely changed from monopole through dipole or cardioid mixed mode. Dunny missed the side shot:

You may have noticed I'm not a big fan of the ill speaker + gauze/bandages approach.. Cure the source I say. Come listen for yourself Chu. And for goodness sakes, drag JNeutron with you. That dude desperately needs to get out of that lab and into the real world of "high end" audio.
Should be plenty of cool ground loop curing cables there.

Amir's secretly sponsoring me. We're actually good pals offline. We just like playing the good cop, bad cop thing here. If I do decide to go commercial and let Madrona carry my line, I'll just have him shill them here for free on AVS. Who would suspect we were in collusion?
See ya there.

cheers,

AJ

p.s. they're undergoing heart transplant surgery at the moment, so won't look quite the same.

my god, maybe you're right!

You mean the one sitting on the table between the listener and speakers? That one? That table?

"Skin lotion"
No naughty thoughts, it's my nieces.

cheers,

AJ

How many offers to people have you made for them to listen to your speakers?

I see you constantly doing it, have yet to find where someone has taken you up on it.

You think it's probably distance, time or summat like that no?

Ever consider that after seeing your online persona that people realise they'd rather drive a four inch building nail thru Mr Happy than spend ten minutes in the same room as you???

If not, I suggest you do consider it.

Now, we have all noticed that you avoided the question. Diffraction remember?

We will continue to watch as you dance around talking about everything BUT. And, when you think we are not looking, we will again note when you restart the attack on others.

How did these stack up when you blind tested them? After all, NO conclusion is valid if you don't blind test something right?

So we will wait for those answers as well.

In vain no doubt.