frequency range for instrument vs speaker

How did that happen? The Audiogon gremlins strike again. I didn't resubmit that post. Nonetheless, sorry.

06-22-12: Onhwy61
I think Frogman is correct, but it should be put into perspective. Suppose you were an audiophile with limited funds. Would you be better off pursuing bass response down to 20Hz, or compromise at 50Hz (with room reinforcement) and put more money into going for a better quality midrange and treble? Unless you're an absolute bass fanatic the answer is self-evident.

It's only "self-evident" to those eager to sacrifice an octave of the music for a little extra refinement. Actually, different music-loving audiophiles split up their priorities and budgets in different ways, and full range frequency response is one of them. All the imaging and transparency in the world can get annoying over time if a conspicuous part of the pitch spectrum is missing.

I think there's a strong case to be made for making a pair of powered subwoofers part of a speaker budget. Not because I'm a bass freak, but because it may be a smarter way to split up the frequency range--and the money. These days there are some stupendous stand-mounted speakers at $3K or less, with transparency, excellent dispersion and therefore uniform power response, treble extension, soundstage and especially pinpoint imaging.

At some point when you build a passive loudspeaker system and you go for full range, a lot of the money is spent on cabinet rigidity and damping to keep the big woofer from smearing the rest of the sound emanating from the higher drivers. With separate subs it's easier to retain the transparency and imaging of the mini-monitor while adding a low frequency foundation that does not cost too much on one hand and doesn't smear the rest of the sound on the other. How many of us have heard a line of speakers where the stand-mounted unit sounded the best while the floorstanding version lost some of the magic just to get another 1/2 octave of bass extension?

With separate powered subs you get to retain the magic while adding the foundation. You also have the option of placing the subwoofers where they mate best with the room. How many times do we move full range speakers around, finding that one spot gives the best midrange/imaging/soundstage but another provides the best bass? It's pretty typical. Separate subs fix that, and you don't have to be a bass freak to appreciate it.

Also, it's more cost-effective. You could get a pair of Cirrus Vapors with the external crossover option, stands, and a pair of JL F112 subs for at least $5K less than a pair of Wilson Sophias. You'd get all that midrange transparency and treble extension of the ribbons, plus inner detail owing to the Herculean bracing and cabinet damping of the Vapors, plus the slam and dynamics of the JL powered subwoofers. The total package is cheaper because you don't have to damp and brace the monitor cabinets to keep deep bass waves under control--they're in a separate box.

If you think you can just buy a subwoofer, drop it into your living room and add an octave to the range of your music, then you are deluding yourselves. Room volume and size plays a much greater role in the low frequency response of a stereo system than with the higher voice range frequencies. Just like discussed, speakers can have a perfectly flat frequency response in an ideal anechoic environment, they do not quite achieve that flat response line in a real world listening environment. Perfectly flat response is a bit dull and boring anyway. I know, I tried that once years ago. I worked hard on my room with an analyzer and anechoic panels to make a flat response at my listening position. It sucked the life out of the music. btw- I had speakers back then had a 20-20k Hz range. I found the bass sounded better way into the next room as compared to my listening position.
When you add a subwoofer to your system and things seem to go deeper, that's mostly because it is reinforcing the 30-40's Hz range. You are not going to hear 20Hz from 12 ft back, ie. not at the same SPL level as the higher frequencies. That wavelength is over 56 feet long. Sure you can fold it over and reflect it back, but you better have some sturdy walls to get efficient reflections and the distances better be just right so it is at the correct phase angle at your ears. Even the 30-40 Hz range have wavelengths over 20ft long so their SPL levels at 12 ft back are not going to be as high as levels in the voice range without some boosting. Just try listening to the grand pipe organ from 12 feet back sometime. You won't hear the low pedals that close to the pipes nearly like being much further back in the building.

06-23-12: Tonywinsc
If you think you can just buy a subwoofer, drop it into your living room and add an octave to the range of your music, then you are deluding yourselves.

Why do I bother qualifying my statements with phrases like "properly blended" in my posts if you bulldoze over them like I never said anything at all. It's not like placement of a 350-lb. pair of full-range speakers with spikes is a piece of cake either.

OF COURSE you have to take special care in placement, phase adjustment, crossover adjustment, and level adjustment. Who on this forum wouldn't know that? I've seamlessly incorporated seven subwoofers into various systems in the past 7 years. I had a pair of subs in my living room and after living with them a few months, took about 4 hours to reposition them and re-adjust their settings. It was well worth it. I can now play large scale orchestral works (Berlioz, anyone?) on this system with engaging and credible reproduction.

Blending subs is a pain in the ass that can take anywhere from 2-4 hours to several days. But if it saves you $5K or more compared to the equivalent passive full range speaker, it's easily worth it.

As for the wavelength argument, my small towers are in an open architecture living room. There's almost no limit to how long a soundwave can form in my house interior--across the LR, up the stairs and down the hall, or across the living room, down the stairs, and out to the 18x22 media room.

Here's another thought: regardless of the size of the venue, if you have a subwoofer putting out a 25 Hz frequency, even if you're sitting well within the fully formed wavelength, the frequency is hitting your eardrums (and flapping your pantsleg) 25 times per second, and your brain will perceive it as such.

By your argument we couldn't hear bass below 180 Hz (about F below middle C) from a car stereo where the maximum interior dimension is around six feet.. Psst... we can.

Johnnyb, you explained it well. It takes a lot of effort and work to get it balanced across the broad spectrum. What I was trying to say is that the long wavelengths are multiple times the length of a typical listening position. So the SPL at 12ft (typical listening position) of a 20Hz frequency is going to be much lower that at 56.5 ft-, ie. the full wavelength. So to make the 20Hz frequency the same loudness at 12ft as shorter wavelengths will take a lot of power and then the loudness of the 20Hz frequency will be much higher as you move out to the 56ft range. Like you said, you have to work very hard to balance all of that out and get it to work. You are taking great pains to get the reflections and the sources to all come together at the listening position. I still doubt you can achieve a balanced 20-20k in a small room.