LF extension and bass performance in speakers...

Discussion in 'Audio Hardware' started by Shiver, Sep 30, 2014.

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  1. Shiver

    Shiver Forum Resident Thread Starter

    Location:
    UK
    Righty, I’ve been looking in to stand-mount speaker options – reading up and looking at the different specs and reviews, wondering where to start trying to listen. (I thought I might have to move in to a small apartment for a while, but now don’t, but still...)

    One thing that I was particularly interested in was LF extension. I’d never want to live with anything bass-light. Seeing the wide differences in similarly priced/pitched models* led me to wonder, in brief:
    • How much does the LF extension of a speaker’s specification reflect how deep it really sounds? (notwithstanding room placement/dynamics).
    • What’s the limiting factor in LF extension in speaker design? Why wouldn’t a designer aim to extend it as far as possible?
    • Are there any rules-of-thumb for speaker design and bass-output/augmentation? – ie to be considered along with specification.
    • How much LF extension does a speaker need in terms of how much recorded music really sits in the, say, 20-50Hz range?
    Perhaps these are naive questions, and I’ve heard enough speakers to know that stats alone, and design, tell you nothing about the character and delivery, etc - but if anyone’s got any particular thoughts/insights regarding this it would be interesting and much appreciated!

    *A few example speakers I considered, all noted for good bass, are (as specified in hi-fi news ( LF/HF extension -6bD ref 200hz/10KHz)):
    • JBL 4312 MII: 80Hz / 11.4KNz / 11.6kHz -
    • PMC twenty.21: 59Hz / 35.6kHz / 36.0kHz (have heard these briefly and they sounded superb)
    • KEF LS50: 42Hz / >40kHz / >40 kHz
     
  2. jupiterboy

    jupiterboy Forum Residue

    Location:
    Buffalo, NY
    Down to 30 is nice. Many speakers are kind of abreviated in the lower registers. Size of driver is an issue, but a transmission line can do wonders where traditional ported designs are a little less focused. I recently went to a stand mount and went through a similar search. I would suggest looking at some other models in the KEF line if you like their sound. Most people use a sub. Designers do try and extend the bass, but driver motion can cause distortion throughout the mids, so a dedicated woofer is what you need for low bass. However, two-way designs tend to image much better and sound less confused. Rated efficiency is going to allow your amp to more easily control the drivers, so that is probably going to effect how well your amp works with any given speaker. In my experience, room can amplify some bass frequencies and remove others, so whatever you do, a little treatment can really help.
     
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  3. Tyler Eaves

    Tyler Eaves Forum Resident

    Location:
    Greenville, NC
    I don't think any of those would offer true deep bass. No small stand mount probably can.

    A key number is 41.5hz. That's the frequency of the low E string on a 4 string bass. You'll want to be able to reproduce that with authority for a true full-range sound. If you listen to much music using a 5/6 string baas (reggae, modern R&B, prog/jam rock, etc), the low B there is 30hz. Probably not really attainable.

    Now, you don't need a speaker to go that low to clearly hear those notes...there are plenty of higher harmonics.

    To give some real world comparison, an Ampeg 15" Bass speaker is -3 at 50hz, and -10 at 33hz.
     
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  4. tim185

    tim185 Forum Resident

    Location:
    Australia
    Don't forget your room has a massive effect on the low end you will hear from any speaker, no matter what the cost. Most rooms have massive nulls in the low end. Need to look as closely at that as you do what type of speaker you buy.
     
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  5. atbolding

    atbolding Forum Resident

    Location:
    Austin, TX
    (small) size, efficiency, low frequency extension - pick two.

    Google Hoffman's Iron Law. (not that Hoffman.)
     
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  6. Shiver

    Shiver Forum Resident Thread Starter

    Location:
    UK
    Thanks for the responses. What I didn't explain clearly enough, sorry, is that I'm no longer looking to buy a standmount any more - just thought I might have to as it looked for a while that I was going to move to a much smaller space, but now don't need to! The questions came from looking in to that initially, and interested me in general around speaker design and LF in particular. I am looking to upgrading the big old Castles to something else, eventually though.

    Really interesting points about the bass frequencies. Knowing that it would forever make me wonder what I was missing if not down there in speaker performance - even if otherwise sounding sweet. (My current speakers go down to around 35 Hz (spec for newer version of the same design/model - can't find the specs for my particular one) and do seem to register a real bass weight... Again I couldn't live without that).

    Good points on speaker design and rooms too - interesting. Sub would seem the way to go if necessity or preference leads to a smaller/non-LF speaker.
     
  7. Tyler Eaves

    Tyler Eaves Forum Resident

    Location:
    Greenville, NC
    If you want an extreme torture test, checkout this video Playing notes on a sub-octave extreme bass...



    The lowest note he's hitting is C#0 which is ~17hz.
     
    Last edited: Sep 30, 2014
    Dance Mxyzptlk and norman_frappe like this.
  8. GuildX700

    GuildX700 Forum Resident

    Location:
    USA
    My Pioneer TZ9's which are big towers with 2x10" drivers put out strong bass at 25 hz which I would expect them to.

    But my much smaller Pioneer DSS-5 surprised the heck out of me with very strong output at 31.5 hz in my rather large basement room. I think for their size that is pretty impressive, 22.5" H x 12.75" x X 11.5" d. Nominal driver size is 1 x10", rear ported, with a dual wound voice coil on the woofer and the crossover sending 2 signals to the driver, one as a "sub" signal.

    Most smaller boxes really don't have that kind output. I will admit however I spent a lot of time experimenting with insulation type, quantity, and placement in the box before I got that kind of low end heft. Stock it fell off rapidly below 50 hz.

    You really need reasonably audible output at 31.5 hz to have a good amount of bass heft for most music (other than pipe organ/electronic).

    Sadly I believe most manufactures ignore good bass output on smaller speakers these days, they just assume the buyers will probably be using subs. If they took more time on testing cabinet tuning with insulation and port tuning (if so designed) I think more of the reasonably sized stand type speakers could have better bass output. JMHO though.
     
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  9. norman_frappe

    norman_frappe Forum Resident

  10. GuildX700

    GuildX700 Forum Resident

    Location:
    USA
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  11. Shiver

    Shiver Forum Resident Thread Starter

    Location:
    UK
    Nice one - away with work at the mo but will try that out through the DAC at home!
     
  12. Shiver

    Shiver Forum Resident Thread Starter

    Location:
    UK
    Well explained, all makes sense to me.
    I was really drawn to the meaningful bass response and presence in my current speakers (helped I think by their design - ported between the speaker cabinet and the plinth and create a sort of loading) and quite a lot of others seem somewhat ‘thin’ in comparison, even if the might have delightful clear mids etc, even other floorstanders.
     
  13. Shiver

    Shiver Forum Resident Thread Starter

    Location:
    UK
    Fascinating table!, thanks. Like a work of interesting art.

    That's live instruments though... how much of that range/depth/height is really captured in recorded music? Could a pipe organ recording (say on CD) really push out a 20 Hz note, given the right equipment? And even if possible does that really happen in recordings?...
     
  14. norman_frappe

    norman_frappe Forum Resident

    you are very welcome.

    Good question. I don't know to be honest, maybe someone more knowledgeable can answer. The way I see it the vast majority of the action is in the 40 Hz and above area. If I can produce down to 50 Hz faithfully and accurately that should be good enough for me I just don't have much interest in the sub bass region. fwiw I feel it more than hear it anyway when I goto live concerts.
     
  15. Tyler Eaves

    Tyler Eaves Forum Resident

    Location:
    Greenville, NC
    Allow me to present a counterargument by way of a sound sample:

    https://mega.co.nz/#!q4NzWLKa!KDk2q8OPyR3327XsrUHWsh7XjyZjxhwFRYE5r7Iluic

    This is a short sequence from the 1st verse of Black Sabbath's Paranoid. It contains the same brief passage twice, once unaltered, the second time with the most extreme high pass I was able to apply in Audacity... 0db at 57hz, -3db at 50hz, -24db at 40hz, and -30db at ~37hz.

    Notice how the kick drum practically dissapears, and the bass sounds odd and almost distorted.
     
  16. GuildX700

    GuildX700 Forum Resident

    Location:
    USA
    My DSS-5 un-modded went down to 50 strong, but fell off a cliff after 50, to me that sounded very thin for bass. So it even if 50 is strong, it still depends what happens below 50 IMO.
     
  17. GuildX700

    GuildX700 Forum Resident

    Location:
    USA
    Electric bass does not have a strong fundamental, take that away and the harmonic overtones are the "noise" that's left. Makes sense.
     
  18. Robin L

    Robin L Musical Omnivore

    Location:
    Fresno, California
    The AR-3's that were my first 'real' speakers went further down than anything I've owned since. However, my current "Frankenstereo" goes at least as far down as the low organ notes in the Saint Saens "Organ Symphony". The combination of the Magnapan mid/bass driver and the 10" driver of the Infinity 2500's appears to go down below 40 hz. Being far from walls and corners keeps it from getting muddy down there, very easy to hear the tunes in the bass.
     
  19. BuddhaBob

    BuddhaBob Forum Resident

    Location:
    Erie, PA, USA
    One reason I have never given up my Koss CM1030s is the bass response. The 6dB down points are 26Hz / 19.5 kHz. I wish they had a bit more at the high freq end, but the imaging is excellent and I can really crank them.

    I have them fused at 6A. They can really handle the watts.
     
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