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I nee Helb for a small 1x10 diy bass cabinet

Discussion in 'Amps and Cabs [BG]' started by Marinus, Apr 10, 2021.


  1. Marinus

    Marinus

    Apr 10, 2021
    I build a lot of Guitar Cabinets, but i never build a bass cabinet.

    I like to build a small 1x10 bass cabinet for homepractice with a Warwick Gnome. The Speaker should be a Jensen BassPunch BP 10/150.

    I never worked with WinISD. So im not sure if my Calculation is rigth.

    Speaker Data:

    FS: 55Hz
    QTS: 0,33
    QMS: 5,93
    QES: 0,35
    RE: 6,1 ohm
    VAS: 42,6 Liter

    My Calculation with WinISD for an Vented Box says Boxvolume 20,55 Liter and and two Vents with Vent Diameter 1,97 inch and 6 ich Vent length.

    Maybe someone could tell me, if this is correct?

    I dont nedd a perfect result. I d like to have fun while the builiding and playing bass in my livingroom.
     
  2. A9X

    A9X

    Dec 27, 2003
    Australia
    Fs is too high for my tastes. E is 41Hz. I'd choose a different driver.
     
  3. SgtHulka

    SgtHulka Supporting Member

    Mar 29, 2019
    Fort Arnold
    Have you seen the diy coffeehouse 1x10 thread? If so my apologies, but if not, it might just have what ur looking for.
     
  4. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    Fs by itself is rather meaningless. There are some outstanding 10” speakers that use drivers with an Fs higher than 41Hz.

    For this project, I would also suggest looking at the DIY coffeehouse 1 x 10” rather than attempting to reinvent the wheel.
     
  5. Passinwind

    Passinwind I know nothing. Commercial User

    Dec 3, 2003
    Columbia River Gorge, WA.
    Owner/Designer &Toaster Tech Passinwind Electronics
  6. A9X

    A9X

    Dec 27, 2003
    Australia
    No, it is not " meaningless ". Sure other designs may use driver with an Fs higher than 41Hz but I would consider them highly compromised and not worth the effort of designing and building one, especially for home practice where size, weight and portability are less of a concern than a gigging rig. In a practice rig I want to be able to hear full range and as I and many many others use 5 and 6 string instruments, it's important both in my opinion and experience.

    I didn't answer because I was in a car and on my phone without Excel which 2 of my design apps need. Nor did I have Soundeasy.
    It's easy to suggest a different design project, but maybe the OP already has the driver.
     
    Last edited: Apr 10, 2021
  7. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    Fs alone does not dictate low frequency performance. It’s one of several parameters that define low frequency performance. There are many drivers with low Fs that make dreadful drivers for bass guitar.
     
    Nickweissmusic likes this.
  8. A9X

    A9X

    Dec 27, 2003
    Australia
    Likewise there are many that are not. There are also many drivers used in commercial designs that I find dreadful.
     
  9. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    And there are many drivers in commercial designs that are outstanding.

    Different players have different tastes, my experience is that most players do not prefer drivers with low Fs because the trade offs necessary for low Fs take away from other driver performance aspects that are more important to them.

    2 examples of off the shelf 10” drivers that I really like for bass guitar (my all time favorites actually for off the shelf parts) are the JBL E-110 and Faital 10PR300. Both have nice low frequency extension in a reasonable size box, an open and natural mid voicing and a smooth high frequency extension. The Fs for the JBL driver is 65Hz and the Faital driver it’s 60Hz.
     
    Last edited: Apr 10, 2021
  10. Nickweissmusic

    Nickweissmusic Knows all intervals from one Fred, to Juan octave Commercial User

    Jan 26, 2014
    San Diego, CA
    I teach lessons and perform live music in and around San Diego CA. Sometimes I even make money doing it!
    gotta love the horse, thanks for the sense injection.
     
    FRoss6788 and agedhorse like this.
  11. Nickweissmusic

    Nickweissmusic Knows all intervals from one Fred, to Juan octave Commercial User

    Jan 26, 2014
    San Diego, CA
    I teach lessons and perform live music in and around San Diego CA. Sometimes I even make money doing it!
    That seems fine, using this quick calculator it looks like a 12”x12”x13” box (sorry for inches, but that’s a nice compact size, I’ll let you do the conversion ;) ) would give you a little more than that volume, but remember some volume gets taken up by the speaker. Maybe the port tubes too? Can’t remember off hand If tubes count against internal volume.

    I think it’s worth a shot, especially since you already know how to build. Bass cabs are definitely more build-sensitive than guitar, and if you want a tried and true design, you’re best sticking with one that’s already been tried and trued by someone else :) . But for an experiment in bass cab design, it seems you’re on the right track, that could be a winner. Only one way to find out! Post your results, I want a small ported cab like that too ;)

    this is the volume/dimension Calc.: Speaker Box Volume Calculator / Designer
     
  12. Bassgeige and Passinwind like this.
  13. 808State

    808State

    Dec 30, 2020
    20 to 35 liters is pretty common volume for a 10"

    20.5 would be on the smaller size.
    Small volumes can work well for power handling as long as the speaker works well mechanically
    in such a small volume.

    Simple approach for vent tuning is to tune to the drivers FS at 55hz
    Which is normal practice for BB4 or SBB4 alignments.
    common Butterworth or Quasi Butterworth filter alignments will usually
    tune 3 to 7 hz above FS

    Your posted vent diameter and length would produce tuning around 55 to 56 Hz
    so it seems like a very straight forward cabinet.

    20.5 liters is feasible. Its just at the very limit of how small you would want to go.

    Keep in mind the driver itself will displace 1.1 liters of volume
    and 2 ports 1.98" diameter 6" length will displace .3 liters each

    1.1 liter speaker volume displacement
    .3 liter 1st port volume displacement
    .3 liter 2nd port volume displacement

    1.7 liters

    If you want the driver to operate in a net volume of 20.55 liters (Vb)

    The total volume of the box (V) needs to be 22.25 liters to make up for the volume the ports and speaker displace.
     
    Last edited: Apr 11, 2021
  14. ThisBass

    ThisBass

    Aug 29, 2012
    Germany
    Personally I'd cut the port length down to abaout 3" of length respectively 4" at most.

    Here you are with the predicted response for a port length that equals 3"

    upload_2021-4-12_0-50-43.png


    And just for comparison the response for 6" port length that noticeable lacks some essential acoustical "power" at low response vers 3" port length.

    upload_2021-4-12_0-49-46.png
     
    agedhorse likes this.
  15. 808State

    808State

    Dec 30, 2020
    Did you calculate with 1 port ? or 2 ports

    The OP is using 2 ports for 55/56 Hz Fb

    3" length is close to 71 Hz.
    which is almost 16 Hz above resonate frequency.

    Once you start tuning 8 Hz over Fs then its too high
    Its making up for what the speaker cant do mechanically.

    A 2 to 3 dB bump in the EQ does the same thing.

    A bass cabinet tuned to 70 hz would unload rather quickly.

    unless you assumed the cab was tuned to 45 hz and then increased tuning to 55 hz which is what the 2 port design was at.

    Assuming we are talking raising the tune only 3 hz.
    Error factor would be in end correction.
    No flare would raise tuning, flare would lower tuning
     
    Last edited: Apr 12, 2021
  16. ThisBass

    ThisBass

    Aug 29, 2012
    Germany
    upload_2021-4-12_18-10-42.png

    3" port length
    upload_2021-4-12_18-12-9.png

    4" port length
    upload_2021-4-12_18-12-56.png

    WinISD is a quite inaccurate tool in any regards of predicted tuning and port dimensions (as you state 71Hz for 3" port length).

    I agree that for 3" port length the resulting number of ~64Hz for the tuning is quite high and may tend to "overload" the speakers Xmax capacity at high volume levels.
    Alternativeley a port length of 4" would improve the power capacity at some content (Fb ~59Hz).


    The OP indends to built a cabinet for homepractice where he (very likely) does have no need to push the cab to highish loudness levels which (of course) would lead to "critcal" cone excursions.
    I think its (either way) a good idea to protect the speaker with a HPF.
     
    Last edited: Apr 12, 2021
    agedhorse likes this.
  17. ThisBass

    ThisBass

    Aug 29, 2012
    Germany
    @808State
    If I remember correctly WinISD provides reliable numbers if only ONE port is used. In addition WinISD expects the port to be placed in the centre of the back plate panel of the cab
     
  18. 808State

    808State

    Dec 30, 2020
    WinIsd uses the same formulas
    In this case, I am sure not intentional, but can happen.

    The Op specified net volume 20.55 liter cabinet and specified 2x 1.98" diameter x 6" length port

    your model included a net volume 22.5 liter cabinet with 2.00" diameter.

    Extremely small volumes like 20 to 35 liters will have dramatic jumps in port tuning with port length and flare.

    Even though 20.55 and 22.5 does not seem large, and 1.98 and 2.00" does not seem large.
    this will cause 3 to 8 Hz jumps in the overall modeled response of the box Fb or tuning




    This is good for any speaker builder to know.
    When working with small volume boxes, very small changes to port length can cause larger jumps in tuning.

    Larger 100 to 170 liter boxes are much more friendly to port length.
    you can have larger errors with port length and not have a dramatic effect on tuning.
     
  19. 808State

    808State

    Dec 30, 2020
    My information was based on the data provided by the OP.
    Again since error factor correction varies with programs and there was 2 liters of error
    and .2 inches of error for ports. Unfortunately yes with such a small net volume.
    Port Tuning was different. Its why I addressed the issue.

    Your model looked good, but when I compared to a correct smaller net volume
    some things did not make sense.

    Overall its good to know, I already thought 20.55 liters was a little on the small side.
    the enclosure could be enlarged slightly to 22 to 25 liters net volume.

    Tuning is just as recommend. Tune to driver Fs at 55/56 Hz or tune slightly higher
    3 to 8hz above Fs or 59 to 64 Hz

    Seems your model showed that basic rules of thumb tend to work. Tuning 8 Hz above Fs can
    increase overall port output, at the tradeoff of quicker unloading.

    With 10" speakers having Fs of around 55 to 65 Hz
    Either way this is a extremely typical 10" box
    20 to 35 liters and 55 to 65 Hz Fb
     
  20. Primary

    Primary TB Assistant

    Here are some related products that TB members are talking about. Clicking on a product will take you to TB’s partner, Primary, where you can find links to TB discussions about these products.

     
    May 8, 2021

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