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Anyone else hate bass boom and ported speakers?

Discussion in 'audio' started by embee67, Oct 3, 2011.

  1. embee67

    embee67 Member

    Hi all,

    Title says it all really. Slowly getting back into music after a long break over the last year or so and being a bit limited in budget have been buying from ebay a fair bit. Oftentimes including various 5 star products of the last few years. Been very difficult though to find any bookshelf speakers I like as pretty much everything has unnatural sounding bass boom from their various ports.

    Love my old Rega hifi and my slightly newer Exposure kit but having tried speakers from various makers including Kef, MA, Dali and even Rega (lovely in every other way) I just can't stand the bass woof coming from the ports which seems to get in the way of actually hearing any specific pitches in basslines.

    Currently using some sealed NAD 801mm (don't laugh!) as they are the only sensible sounding speakers I've heard which avoid this boom and for all their cheapness actually present music in an enjoyable way to me. Am I some kind of freak? Does anyone else find this annoying? I live in a small apartment and I want to listen fairly quietly but would like to spend on decent speakers with lots of detail and resolution. Can anyone help me with a few suggestions?

    Cheers
    Mark
     
  2. Tenson

    Tenson Trade: AudioSmile

  3. bottleneck

    bottleneck pfm Member

    its not the ports that are the problem, Its almost certainly the dimensions of your small flat augmenting certain bass frequencies. This is obviously my opinion.

    For example the speakers below (my first reccomendation) are in fact ported. You wont notice that, they are ideal near field monitors, and have a lot of detail there for you.

    You need a powerful amp if you're unfamiliar with them.

    http://www.ebay.co.uk/itm/Acoustic-...omeAudioHiFi_HiFiSpeakers&hash=item1e673f1eb8

    At the budget end of the market, I find missions work in the near field (I used them in a 7x8 foot room). Also Epos ES11's too, sligthly cheaper than the AE1's.


    *edit*
    simon beat me to it!
     
  4. Michael J

    Michael J pfm Member

    You're not alone, OP. I don't like puffers either.

    I currently have at least seven pairs of speakers to choose from, small through to quite large (JPW mini monitors and Sonatas, Mordaunt-Short MS20, B&W DM220/330 and DM600i), none are ported. :)
     
  5. darrylfunk

    darrylfunk Banned

    none are good either....:)
     
  6. darrylfunk

    darrylfunk Banned

    i used to really like the mordaunt ms100 and ms300.....but it's not generally the port itself but it's alignment and damping of the design and how it coincides with room eigen tones.
    as mr neck and tenson have pointed out.
     
  7. S-Man

    S-Man Kinkless Tetrode Admirer

    I would suggest JR149s, Sterling 3/5As, Harbeth P3 variants and Spendor SA1. Also small 2-way ATCs e.g SCM7.

    There are 2 things to look for:
    1) Sealed boxes = high but gentle bass rolloff :- integrates well in a small room.
    2) Minimal baffle step compensation :- so that they can be used near a wall.

    Some people seem to be very sensitive to the poor transient response that most ported speakers suffer from (or maybe most people have just got used to the sound of them).
     
  8. James

    James Lord of the Erg\o/s

    Ports work over a narrow range, where the dominant output of the loudspeaker system is effectively a fourth order system and not under the direct control of the amplifier. So when the signal stops abruptly, the port will continue to resonate for a few nano-seconds (or more) longer. No matter how well designed, this is the nature of ports and how they work.

    If that resonant band coincides with a room mode and the loudspeaker is located to couple sympathetically with that mode, then you'll get that characteristic boom. Not pleasant and certainly not tuneful.

    Sealed woofers resonate too at fb. But this is a second order system and the driver is the only thing resonating (barring lousy cabinetry). Thankfully, this resonating driver is also under the direct control of the amplifier and is going to stop far more quickly than the ported equivalent.

    The transient response of sealed systems is generally better than ported systems for these reasons. I'll get off my soapbox now ...

    James
     
  9. arthur

    arthur Banned

    You could try and find a pair of AVI's Biggatrons.

    Loved mine and they are as clean chuff-wise as you'll find.

    I think they like it up 'em though.
     
  10. Michael J

    Michael J pfm Member

    :eek:

    You haven't heard my modified ones. :)
     
  11. S-Man

    S-Man Kinkless Tetrode Admirer

    I always thought it was because the pressure wave from the back of the driver (out of phase with the front) was delayed by 1/2 a wavelength by the port tuning so that it adds to the front output. The problem with this is it adds on the next cycle, which is fine with a continuous tone but not much use with transient signals.
     
  12. bennyboyph

    bennyboyph pfm Member


    Naim SBLs may be to your liking, but they do require more attention to setup properly.
     
  13. embee67

    embee67 Member

    Ahh, thank you so much guys! Never really occurred to me that the construction of our building could be causing it. Mind you, buying a new London flat to cure it must surely be one of the biggest hifi investments ever! And a bit beyond my reach at the moment too :)

    Tenson's links are quite clear that I have issues relating to a long yet narrow living/kitchen area and walls made from cardboard (or whatever is cheapest these days!) so like bottleneck also guessed I suppose some kind of treatment will probably be necessary.

    Thanks for the suggestions too. Like S-man suggests it just seems to be something I find very noticeable (and obviously annoying) and I was thinking BBC-type monitors but I'm too poor to pay even some of the second hand prices on these. Glad too to hear the ATC SCM7 mentioned as I was considering these based on reviews but again a fair bit to save up only to find they sound bad when I get them back home. Either way its nice to get some confirmation I might be thinking along the right lines.
     
  14. James

    James Lord of the Erg\o/s

    Possibly, but at LF, the wavelength is academic. The inertia of the air mass in the port is a bigger contributor to transient response. The bigger the air mass relative to the woofer, the worse the transient response.

    It's the difference between a sprung wheel with and without an effective shock absorber.

    James
     
  15. Tenson

    Tenson Trade: AudioSmile

    It's probably the narrow width resonance you are hearing. Do you have the speakers placed symmetrically in the room (equal distance from each side wall)? If so, try off-setting the speakers and listening spot so you don't sit bang in the middle of that dimension.
     
  16. Cereal Killer

    Cereal Killer fourhundredandthirtytwo

    Surprisingly my Spendor SP1/2R's don't chuff one bit and they're ported. Very tuneful deep bass.
     
  17. Rico

    Rico Registered User

    you're clearly lacking committment. if we were back ten years or so, a quick visit from the Jawed and Dev mafia would have your ports chuffing and your crossovers on fire.

    ports are the work of the devil.
     
  18. irons1965

    irons1965 pfm Member

    I've just upgraded my speakers to PMC FB1i's (transmission line bass) and they have excellent tight bass....This was a major consideration for me when auditioning, I simply cannot listen to anything with slow flabby bass.
     
  19. Cereal Killer

    Cereal Killer fourhundredandthirtytwo

    Bad curry was it??
     
  20. RJohan

    RJohan pfm Member

    One can always try sticking some old socks hard into the port of a bass reflex speaker. This converts them into sealed boxes, if one doesn't like the result, just remove the socks again. A free, reversable tweak!

    My main concerns with reflex speakers are two:
    - The port usually puts out some midrange rubbish from inside the box.
    - A reflex box has damping material only along the walls of the inside. This is far from sufficient to control standing waves inside the box. Closed box speakers are usually filled with damping stuff.

    The transient response of a low frequency system (bass) is up to the alignement as long as the bass driver is in it's linear working range. That means that the voice coil is inside the magnetic gap. It is when part of the voice coil is leaving the magnetic gap (let's asy, on a fast, hard transient from a bass drum) that things starts to get seriously wrong in a bass reflex design. Now the electrical damping (Qe) of the driver gets much lower so the driver can't control the mass in the port. It is actually possible for the mass in the port to drag the cone even further out from it's linear range! The result, really bad sound.
    This kills the spread missconception that you can play louder with a bass reflex speaker (everything else equal vs the closed box).

    Won't bore you anymore / JohanR
     

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