Please explain what "low frequency extension" really means :)

[kexodusc]

I see speaker specifications often employ "low frequency extension"...is this a realiable measure as to how low a speaker's frequency response is? If I see "low frequency extension" posted at say 35 Hz (DIN), will I hear frequencies in this range at a reasonable close volume to the other frequencies out put by a speaker?
And what does the (DIN) mean?
Thanks.

[topspeed]

I see speaker specifications often employ "low frequency extension"...is this a realiable measure as to how low a speaker's frequency response is? If I see "low frequency extension" posted at say 35 Hz (DIN), will I hear frequencies in this range at a reasonable close volume to the other frequencies out put by a speaker?
And what does the (DIN) mean?
Thanks.

Hey KC,

This is likely marketing jargon for frequency range. Yes, you can hear 35hz but how loud it will be in comparison to the upper freq's will depend on the design. Obviously, speakers w/ built-in subs like DefTech's BP towers will have a ton of energy in the lower octaves due to their built-in subs.

You bring up an interesting point tho and I'd like to add on to it. Can someone explain the difference between frequency response and frequency range? B&W posts both and I've always considered the freq. response to be the real world reference as it states the range +-3db whereas freq. range is the actual dynamic capabilities of the drivers before rolling off more than -6db's thereby rendering it inaudible. Am I wrong? Also, VSA quotes both anachoic and in-room freq. response. with in-room obviously having better low extension from wall reinforcement.

Isn't there some kind of standard out there?

[Pat D]

I see speaker specifications often employ "low frequency extension"...is this a realiable measure as to how low a speaker's frequency response is? If I see "low frequency extension" posted at say 35 Hz (DIN), will I hear frequencies in this range at a reasonable close volume to the other frequencies out put by a speaker?
And what does the (DIN) mean?
Thanks.
Well, the bass response in an enclosed space will be boosted below the fundamental resonance of that space. Hence, in a room, the bass response goes lower than in an anechoic or free field (i.e., outdoors) environment. DIN means something like Deutsche Industrie Normen, a German Industrial Standard, and there are thousands of them. The particular standard is meant to indicate how low a speaker can maintain a flat response in a typical room, and it is actually a fairly useful spec. For example, a speaker might have a half power point in the bass (-3dB) at 40 Hz, but useful bass response in a typical room down to 30 Hz, where the anechoic response may be about 10 dB down.

How well you can "hear" down that low is another matter, as the ear is much less sensitive at low frequencies than in in the midrange and upper midrange, depending on the level. Look up 'Fletcher-Munson' curves.

[RGA]

I strongly suggest you listen because I have heard speakers rated at 40hz -3d and others rated at 40hz -3db and both speakers even though they measure similarly sound entirely different in the bass region. Perhaps they have the same limit but it doesn't SEEM that way to the ear. And for a very odd reason a lot of speakers when you start to put them up in volume the bass gets a little light in the loafers - this occurred a lot until I bought my new speakers - though My Wharfedales have no trouble playing at loud levels while maintaining bass.

So you have many speakers that compress quickly and seem to only have deep bass at low volumes and others that seem to want you to put the speaker up to get any bass --both designs are lousy and seem to be the norm.

[WmAx]

I have heard speakers rated at 40hz -3d and others rated at 40hz -3db and both speakers even though they measure similarly sound entirely different in the bass region. Perhaps they have the same limit but it doesn't SEEM that way to the ear.
A manufacturer spec is not nescarrily fact. Secondly, "-3d" does not say much, really. ONe needs to see an actual amplitude vs. frequency plot. Speaker A could be down -3db using a higher Q response target then speaker B, which has the same -3db specification. Speaker B will respond deeper, and with less energy storage(ringing, which may or may not be audible, especially considering room effects). Third, unless you heard the speakers in the same room, at the same listening position and each speaker placed in teh precise same place when auditioning/testing, then the response will be different, even if they have precisely the same amplitude response in anechoic/nearfield conditions. The 1/2 and 1/4 wave effects dictated by room boundaries relative to your listenig position and speaker position will have signficant effects.

-Chris

[Woochifer]

My understanding is the way that Paradigm uses low frequency extension is in the context of what a listener might expect to hear in a typical room. Their frequency response is measured in an anecholic chamber, and the way that room acoustics work, it's highly unlikely that you'll get an in-room response within spec, especially as you get into the lower frequencies.

Just as an example, Paradigm claimed a low frequency extension down to 35 Hz for the Studio 40s. From my own in-room measurements, I will confirm that's true. However, it also does not take into account some of the room induced peaks and nulls that occur elsewhere in the 35-80 Hz range, and how that can vary in different locations within the same room. As with all specs, the low frequency extension is something you have to take with a grain of salt, and be aware of what influences real world performance.

[RGA]

A manufacturer spec is not nescarrily fact. Secondly, "-3d" does not say much, really. ONe needs to see an actual amplitude vs. frequency plot. Speaker A could be down -3db using a higher Q response target then speaker B, which has the same -3db specification. Speaker B will respond deeper, and with less energy storage(ringing, which may or may not be audible, especially considering room effects). Third, unless you heard the speakers in the same room, at the same listening position and each speaker placed in teh precise same place when auditioning/testing, then the response will be different, even if they have precisely the same amplitude response in anechoic/nearfield conditions. The 1/2 and 1/4 wave effects dictated by room boundaries relative to your listenig position and speaker position will have signficant effects.

-Chris

And this is another reason specs mean nothing. As you say you need the speaker in the same position to be fair but this would be a dis service to my speakers which are meant for a corner placement. They sound fine free-standing and Audio Note rates the speaker at a free-standing position largely because many spekaers you compare it too would sound completely awful in a corner. Plus you need to know how they're measuring. Audio Note measures at a reasonable listening position. In a corner -6db the bass basically adds another octave going from 50 to 36 and unlike some speakers bass does not thin out at higher volume levels. Distortion figures are rarely provided but the AN's seem to have outstanding specs in that regard.

Alas go and listen.

[bturk667]

The only thing I want to add is that just because a speaker can have good bass extension does not mean that the bass is going to be visceral, but it will be deep.