+ Reply to Thread
Page 1 of 5 123 ... LastLast
Results 1 to 10 of 44

Thread: Speaker Box Suggestions Request

  1. #1
    Join Date: Nov 2014

    Location: Leicestershire

    Posts: 180
    I'm Mark.

    Default Speaker Box Suggestions Request

    Hi Clever People,
    I have just come across 2 pairs of Infinity 655i Co-Axial car speakers in my loft - I had forgotten that they were up there (since 1998!!!), and I was wondering if some kind soul might suggest a suitable box dimension for them. I reckon they'd sound fairly good (if memory serves me well, which is most definitely NOT to be assumed!!!).
    Thanks in hopeful anticipation!!!

    Sent from my LG-H850 using Tapatalk

  2. #2
    Join Date: Oct 2013

    Location: Hartlepool

    Posts: 284
    I'm Martin.

    Default

    How about these for a cheap project http://www.ebay.co.uk/itm/SLIM-PAIR-...IAAMXQYwFRhmY~ Probably a tad small for home use but it will give you a taster.


    Tried the Infinity Kappas 6x9 in the oval alternatives to these boxes on a big class A ss amp in the front room, be fun, with a woofer, in an open baffle.
    Last edited by Hudz; 31-01-2018 at 00:16.
    We are the love we leave behind.

  3. #3
    Join Date: Oct 2016

    Location: Bolton, England

    Posts: 1,300
    I'm Andrew.

    Default

    Some drive units are best suited to ported enclosures and others are best suited to sealed boxes. Some will be ok in either. Lets assume yours will be ok for either. A sealed box is simpler and a lot less likely to go horribly wrong because there's only one parameter to worry about - box size. Ported enclosures are a lot more complicated because you have the box size to get right and the port size to get right, and if you get them wrong you can end up with a horrible bass boom. For that reason I'd be tempted to go for a sealed box. If the box is too small you'll get a bass hump and if the box is too large you'll get clean but possibly weak bass. Fortunately, there's some latitude so there's a good chance the performance won't be too far off.
    Personally, I'd guess at a box size that looks a bit on the large side for the drivers and hope for the best. Of course, if you can find the driver parameters online somewhere you can eliminate a lot of guesswork.

  4. #4
    Join Date: Aug 2009

    Location: Staffordshire, England

    Posts: 21,563
    I'm Martin.

    Default

    No way to calculate the box sixe without the driver parameters.

    You could try fitting them into the end of a very long length of plastic drainpipe and try to make a 'true' transmission line. In theory it should work and a lot less hassle than knocking up cabinets.
    Martin



    Current Lash Up:

    Technics SL1200P CD Player * NVA P90SA passive pre / Krell KSA50S Power amp * JM Lab Electra 926 loudspeakers *


    'This is the sort of music I'd be listening to if I was going shopping for a training bra.'

  5. #5
    Join Date: Oct 2016

    Location: Bolton, England

    Posts: 1,300
    I'm Andrew.

    Default

    I looked up those speakers and found this spec sheet:
    https://www.infinityspeakers.com/on/...-Primus-OM.PDF

    Your particular model isn't on the list but I'd take a guess that other speakers from the same manufacturer have similar specs - after all, they're all intended for use in a car so there's no room for enormous cabinets and I doubt the different models would be wildly different.

    You could use those specs and a simple piece of software such as this...
    http://www.mh-audio.nl/CBC.asp
    ... to calculate the box size.

    Using the specs for the Infinity PR6512is and a ten litre box the software predicts a 4dB bass hump at 100Hz. A twenty litre box gives a 3dB hump at about 95Hz. The software predicts that the box has to be enormous to eliminate the hump completely. 200L gives a hump about 1.7dB.
    That's all for a sealed box btw.
    I would just make a box about as big as you think practical for the space you have - and hope for the best

    BTW, all the above is based on what I would with a pair of old speakers which I'd found in the loft. Bear in mind I don't claim to be a loudspeaker expert and I'm sure there are plenty of forum members with more knowledge and experience in speaker design/building than me.
    Last edited by RothwellAudio; 31-01-2018 at 13:41.

  6. #6
    Join Date: Aug 2009

    Location: Staffordshire, England

    Posts: 21,563
    I'm Martin.

    Default

    200 litres! That sounds about right for a decent speaker.
    Martin



    Current Lash Up:

    Technics SL1200P CD Player * NVA P90SA passive pre / Krell KSA50S Power amp * JM Lab Electra 926 loudspeakers *


    'This is the sort of music I'd be listening to if I was going shopping for a training bra.'

  7. #7
    Join Date: Apr 2012

    Location: Southall, West London

    Posts: 36,174
    I'm Geoff.

    Default

    Quote Originally Posted by Macca View Post
    200 litres! That sounds about right for a decent speaker.
    Or coal bunker.

  8. #8
    Join Date: Aug 2009

    Location: Staffordshire, England

    Posts: 21,563
    I'm Martin.

    Default

    You want to keep a bit of a bass hump around 100hz anyway. Otherwise will sound a bit light in the bass.
    Martin



    Current Lash Up:

    Technics SL1200P CD Player * NVA P90SA passive pre / Krell KSA50S Power amp * JM Lab Electra 926 loudspeakers *


    'This is the sort of music I'd be listening to if I was going shopping for a training bra.'

  9. #9
    Join Date: Oct 2016

    Location: Bolton, England

    Posts: 1,300
    I'm Andrew.

    Default

    Quote Originally Posted by Macca View Post
    You want to keep a bit of a bass hump around 100hz anyway. Otherwise will sound a bit light in the bass.
    Yes, I agree. No point in aiming for a ruler-flat bass response and building enormous cabs when in fact a slight bass hump is beneficial.
    BTW, those calculations are worth double checking. I bunged the figures into the software pretty quickly and might have made a mistake.

  10. #10
    Join Date: Jul 2016

    Location: Welsh Borders

    Posts: 254
    I'm Gary.

    Default

    I have got a pair of recently vacated sealed-box speaker enclosures you are welcome to have for the purposes of experimentation if you want. They are ex-KEF Celestes, so about 1965, built like a brick what-not and about 14 litres in capacity. They are not in bad nick either. Yours for the price of getting them to you (or you are welcome to collect if you would prefer). PM me if interested.
    IB

+ Reply to Thread
Page 1 of 5 123 ... LastLast



 

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •