Most people will probably say "20 Hz.", but it is arguably neither necessary nor desirable to have a speaker that is flat all the way down to 20 Hz.
One reason is that most rooms amplify very low frequency signals (the phenomenon is called "room gain"), and having a speaker that starts to run out of gas at, say, 30 Hz., will not matter too much in many cases, as the room can fill the last octave back in to a large extent.
In addition, a speaker that has real 20 Hz. performance is going to be hard to place properly in many (if not most) circumstances, and can wind up giving peaky, uneven bass as a result (that will drive you nuts over time).
Finally, and there are a lot of people who will disagree with this (e.g., subwoofer manufacturers), much of the information on a recording taking place at really low frequencies is, to my ears, amusical junk, like subways going under the studio and mike stand bumps, that I can live without. Then again, if you find that such noises help make the recording sound more "live" or if you are a pipe organ music fan, you'll want deep bass capability in your system.
I would buy a Radio Shack meter* and get a test CD with bass warble tracks (Stereophile Test CD 3, for example) to measure the bass performance with your current speakers. You may already have plenty of low bass.
* Make sure you use the correction chart to correct for the Radio Shack meter calibration errors.
Getting bass down low with honest power is not easy. You have to deal with the laws of physics. A rough guess would be that 90% of speakers claiming bass to 30hz are putting out too little to seem realistic imo. You need to be able to move alot of air and drivers that can handle it. Without a sub you're looking at speakers with large cabinets.
There's plenty out there but don't believe the advertising claims of most speaker manufacturers because like I said most speakers I've heard claiming bass to 30hz and lower simply have no power down low to speak of. I actually run a sub with speakers that have power into the twenties and run them full range with a sub. The sub is crossed over at 45hz and it amazes me how much that sub is working. I will feel the passive radiator to see how much it's working and it's quite significant. I listen mostly to jazz and pop and that woofer has a pretty fair amount of work to do. Get as much bass power as you can if you want real bass.
The other downside to bass is you will have to deal with large cabinets as no mini monitors can do it, period. If your friend can afford the space and money then find some speakers that claim a minimum of 30hz or you'll end up needing a sub.
The room gain the above poster speaks of will vary depending on the dimensions of the room and the proximity of the speakers to the walls. This room gain is almost always added to manufacturers frequency response claims and is therefore little more than useless if you're looking for an accurate and consistent reference.
I have an elaborate array of subwoofers, and for some music, organ in particular, they have plenty to do. But, my main speakers are Maggie MG1.6, and they fall off fast at 40 Hz. However, the Maggies, when used without subwoofer help, (but with a 600 watt amp) actually sound as if they have "good bass" for most music. I have heard it said that their SMOOTH frequency response is the reason.
My experience indicates that the quality of the bass response is more important than how low it goes. Measures that a speaker designer can use to extend LF response can achieve that goal, but often results in "boomy" bass that sounds impressive in the showroom, but becomes annoying at home.
GREAT INFORMATION!!!!!!!!!!! THANKS A BUNCH
electric bass goes down to 41 hz. organ can go down into the 20's. it depends what you listen to. blues , rock, jazz and most music are happy with 40 hz performance. pro sound PA and bass gear is built to go down to 40 hz, so other than organ and home theater we don't get to hear much music below 40 hz, live or recorded.
It is awfully hard to find "full range" speakers that go down to
20Hz and the ones that do, are usually very expensive. I agree with
Eldartford, I would rather have limited range speakers than speakers that do
bass badly -- and, to my ears, there are many, many speakers that do bass
badly. If you are listening to rock music, you probably want some bass slam.
Getting that slam will be a function of two things; Speakers capable of that
bass and amplifiers that can control the speakers. Most likely, you're talking
about solid state amplifier and you'll need a fair amount of power. I would
call any speaker that can give a relatively flat response down to the mid
twenties, "full range."
As far as room response, you can go to various web-sites and feed the
dimensions of your room into a simulator and it will predict the frequency
response of your room. Having fed lots and lots of dimensions into these
simulators, it seems to me that most rooms have large peaks and valleys
between 35Hz and 100Hz.
This is why many acoustical consultants recommend using a sub-woofer with
a parametic equalizer -- to smooth out the bass response in the room.
Here is one of those room simulators --
One issue that never gets mentioned is the SPL (loudness) at which the LF extension is measured. At very low volume I can get close to 20 Hz with some small Dynaudio speakers which I have. But, as you turn the volume up, the bass volume stays the same, so that at normal listening level the 20 Hz capability is for all practical purposes, zero.
IMHO, frequency response should be spec'd at some SPL. Perhaps the same level used for the sensitivity spec.
I feel that 30hz and below could safely be called full range...not a lot going on down this low but still low enough to give the heft that full range has over speakers that can't go below 35hz or so.
Bass slam never takes place at these low freq's...I would say 35-40hz limited speakers will provide plenty of slam if thats what you are after. At around 30hz things like room-shudder (thats what I call it anyway) can set in...this can be very pleasing if your room is built well enough to have also achieved room-lock and of course is part of the music (new age comes to mind).
The lowest fundamental tone a string bass plays is at 41hz per second.
The treatment of overtones is not relevant to your question but remember the difference tones. A difference tone could be called an "undertone". A fundadmental of 41 will generate a difference tone of 20.5,which will generate a difference tone of 10.25 and so forth. These later tones are felt as much as heard and are responsible for the visceral ambience in a live performace that is(for me) outrageously expensive to recreate.
A poster above mentions an elaborate array of subwoofers and based upon the quality of his posts,I believe he has recreated that ambience.
I'm not a subwoofer guy(which is my problem,of course) and am happy if enough of the fundamentalsin the forties and fifties are present to represent the harmonies involved.
Hope your friend finds speakers he likes.
You may want to conduct a simple test. Go to an audio salon, and listen to whichever speakers you like, both with and without a subwoofer. You may notice quite a discernable difference when the subwoofer plays.
I heard a REL subwoofer in such a demonstration, and was amazed at how much "fuller" even quiet passages with vocals sounded with the sub!
I also owned Maggie 1.6's for a while, and was content with their bass, for a while. However, after adding a Vandersteen sub, found that it improved the entire listening experience dramatically. It's strange, but having those lower frequencies seems to take some of the edge off the highs...
It was recommended to me by an owner of a high end audio store that I should run a pair of subs, since there's plenty of low freq. information sent to each channel. I ended up buying his own pair of Vandersteen 2W subs. It's true, especially if listinging to such music as smooth jazz, synthesized, etc., two subs do make a stereo image of the low end. With one sub, you hear the boom, with two, you hear which side the boom is coming from!
Now I'm running tiwn pairs of Eminent Technology LFT-8a's with tiwn Vandersteen subs. That's a total of 10 eight inch drivers for bass. It's incredible! Powerful, precise bass, without distortion. It doesn't have to play loud to sound authoritative.
Once you familiarize yourself with good, clean lower frequencies, you'll know when you're missing it listening to other speakers/systems.
Two times I have tried monitors with subs, and both times I went back to floor standing full range speakers. If you want good bass representation in your system, do full range floor standers, and subs. But as previous posters have said, better quality with a couple less hz than boomy boxes with distortion.
You may want to read reviews of speakers on audioreview.com
Some good affordable speakers I have used with clean bass are Vandersteens, Magnepans, Eminent Technology (I switched from Vandys, to Maggies to Eminents).
For economy you can even go with a setup like a pair of Wharfedale Diamond 8.3's coupled with a sub. I had a pair of them in my system and was amazed how good they sounded for an economical speaker. Great bass. Biwire them or biamp them and you'll have nice sound. It's all how many $ you want to throw at the issue.
Here is a website with information that may be interesting to you. It is from TNT and describes instruments and their frequency range, as well as their volume.
It is surprising to most that the concert piano goes down to 27.5 Hz. Of course, there is synthesized sound, organ, bass drum, and even cannons (1812 Overture)!
If you believe the tests that sub manufacturers have done, there is subsonic information that adds to the perception of sound. Plus, everyone has different sensitivity and abilities to perceive sound frequencies. I believe that most reproduced music in our homes needs a subwoofer to deliver all the information. I use a Hsu VTF-3R Mark II below 50 Hz underneath my Dynaudio Audience 70s (measured at -3 dB at 34 Hz), and, in another room, an REL Q108E under my Von Schweikert VR-1s. Good luck!
Not many speakers are able to do justice to frequecy around 30 Hz or so and those that do are not cheap at all. I also owned Maggies at one time and I think that they are better capable of reproducing bass than most box speakers at similar price level (cleaner). Lowest note which a piano can handle is 27.5 but is rearely heard in any music CD. Next up the range is the double bass which goes down to 41.5 Hz on its own.
I would choose high quality speakers (the best one can afford) and stick to its lowest frequency reproduction capability at/around 40 Hz or so. A speaker like this would probabaly take care of 99 percent of the albums in general.
If more bass extention is needed, a sealed subwoofer like Rel Strata will come in handy, which is extremly versatile in coping with real world room acoustics.
All the above is just my own personal opinion, based on the various equipment that I owned over the years.