Trying to build box for two hertz 12" subs

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Trying to build box for two hertz 12" subs

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Trying to build square vented box for 2 12" hertz sx300d couldn't figure out how to get the dimensions

For 1 single....

VB 28.78

Fb 37.7hz

f3 32.91 

vas 20

qts.  .47

fs 46 yz

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  • Yes, the basket and motor will always reduce the internal volume and often needs to be accounted for, unless one is going by manufacturer's recommended volumes and they (the manufacturer) have accounted for displacement of the subwoofer. It is often stated in the manual if it's been accounted for or not.

  • Ok I'm looking at this  Do you think this would work well for my two hertz sx300d's

  • If I were to buy a prefab box with net airspace of 1.35 ft3 does my subwoofer take up some of that space hertz sx300d

  • Looking at this sub box will this work well for my 12" hertz sx300d

  • Merged all your threads, though it looks a little messy now, sorry.

    Alright, so what have we here.

    Your Hertz sub is definitely more SPL oriented.

    According to the manual, 1cuft is what is recommended (oddly enough for both sealed and ported) and includes sub displacement.

    So, the enclosure you listed is a little larger than "recommended".

    Now that's not to say it'd be bad, it depends on what you're looking for in output and the sound.

    Displacement of the motor of the sub is .102cuft. BTW.

  • I wanna get more output than anything I don't wanna lose all my sound tho it is very small the recommended enclosure I'm thinking maybe if going a lot bigger I found this as well            I was talking to a guy who sells hertz and said the recommended size is the same for the high energy subs and to look for a bigger box ? 

  • Really? That's not what I was seeing based on the manuals. The manual for the SPL Show indicates 1cuft for every enclosure (perhaps a misprint), while the High energy actually shows different sizes for each. Given you are looking at ported, I'll quote the ported for the HiEnergy.


    .77cuft tuned to 44Hz


    1.23cuft to 40Hz.

    Anyways, manufacturers tend to list the smallest enclosure that still yield acceptable performance, as many consumers don't wish to give up all their cargo room. That said, going larger than what the manufacturer lists, you'll sacrifice power handling of the driver. However, low end extension will be greater.

    If the highest output is desired over all, go with a one note wonder of an enclosure. It'll sound like crap with music (IMO), but it'll be loud. Shoot for an enclosure tuned higher. Just be aware that you will need a subsonic/infrasonic filter active within 5Hz below the port tuning of the enclosure you use to protect the driver.

    The enclosure you listed most recently probably won't be louder than the initial one you listed.

    Larger enclosures tend to be tuned lower and yield a flatter response (desired more by those seeking SQ).

    If you really want SPL over anything, model the driver in a program like winISD Pro and find what enclosure gives the greatest output.

  • Ok with all that being said you say if I go with a bigger box I'm going to lose sq correct? 

    If I go with the atrend box I'm going to have a little extra air space and a port tuned at 38hz I should be able to pound my buddy's ears off right ? At the same time my mom could listened to Fleetwood mac and it's still going to sound good ? 

    I should add I will be running hertz hp1d and this going to be in an suv lots of room

  • Also the ported for the high energy at performance is 1.23cubic feet tuned at 40 hz weird cause the spl was what 1.1? Weird eh

  • No, not SQ, but SPL output, as the driver will not handle as high of power.

    This is NOT a SQ oriented driver, it is SPL oriented.

    If pounding your buddies ears off is the goal, then (and one would need/want to plot the sub in various enclosures to confirm) you'd likely want to place the subs in an enclosure right around or slightly larger than recommended and  tuned higher so they can handle rated power and get a boost in output due to the car's acoustics applying a gain on the frequencies around it's resonance frequency.

    Historically, enclosures tuned to say 60Hz could REALLY pound, but they (in my and many other's opinion) sound like crap with music. Enclosures that typically sound really good with music don't exactly pound.

    It's a give and take. Hertz surely listed what they feel is the best balance among SQ, SPL, and enclosure size.

    If I may, what have you ran the single SPL Show sub in previously? How did it sound? Having two will double you cone area and you'll be doubling your power, going from 700RMS to 1400RMS. You should gain 6dB with the new setup if you use the same size and tuned enclosure as you had previously.

    Two ported 12's getting 1400RMS will get quite loud, no doubt about that, but I don't know just how loud you are looking to get or are expecting. You're not going to be hitting 150dB or anything like that. 130dB would be an easily reached level, maybe even 140dB.

    As for it sounding good with Fleetwood Mac for your Mom, that's completely subjective. One would surely want to dial down the subwoofer level on the HU, unless your Mom is a bass head too.

    IMO (didn't plot the driver or anything) the Atrend enclosure would be a decent route, as far as prefab goes. It's 1.35cuft tuned to 38Hz. Once you install the subs, the internal volume will be reduced to 1.25cuft and the tuning frequency will rise to 39Hz. This isn't too far off the recommended enclosure, so it should sound decent and with there being two divers and then the power, it should get acceptably loud for you.

  • awesome thanks a lot   There is also one other enclosure that I found it's called "ground shaker"  just unsure of he quality maybe atrend is better ?    

    Right now now they're in bassworx box with 1.25  tuned to 36hzthey sound great I just want to get more out of them

  • The Ground Shaker "may sound better", but is unlikely to be louder overall, due to the lower tuning.

    Not a lot of difference between the Atrend and bassworx, though I'd suspect the Atrend to be capable of being slightly louder, just not able to play quite as deep with as much authority.

    If I were you, I'd plot the subs in your current enclosure, then in all the enclosures you were considering, then base my decision off the projected response curve and estimated output. WinISD Pro is free to use.

  • Thanks a lot I just can't use winISD because I don't have a computer only an iPhone and I pad

  • Alright, so playing around with the subs in various enclosures in WinISD, it would seem that you'll get a slight bump in output changing to the 1.35 tuned to 38Hz, and I mean slight. It may not be all that audible.

    Really, if you are all about output, the higher the tuning and the larger the enclosure, the greater the output, but at the cost of low end excursion and potentially, power handling, which would then cause the total output to take a hit.

    Seems you could get away with even a 2.5cuft per sub enclosure without running into issues of hitting the sub's Xmax on 1400RMS for the pair. The higher the tuning, the greater the PEAK SPL output, but again, the deeper bass will be much weaker the higher you tune the enclosure. 2.5cuft per chamber with a 60Hz tuning would result in a massive bump in output, but everything below 50Hz would be have less authority.

    This would be great if you're wanting to make a burp box in which all you want is intense output. Be horrible if you are actually wanting to listen to music with it.

    After playing around for a bit, it seems to me, that what would give the best performance (good amount of output without loosing a lot of your low end excursion), would be something in the neighborhood of 2-2.5cuft per driver, tuned anywhere from 35-40Hz.

    Should do pretty well with Rap/Hip Hop even and probably not sound half bad with most other music if you dial down the sub level. Only thing that may not do so well would be remixed/chopped/boosted music.

    Should be able to get 140dB from a 40hz tuned enclosure in the 4-5cuft (total) range.

    And if WinISD is correct in excursion, you should be able to set the 24dB/oct SSF on your amp at 25Hz and be  perfectly fine.

  •  thanks a lot  I really appreciate it would it be ok to go a little lower then 35 hz I found two boxes tuned to 32hz and one two 38 hz