Bass reflex box

Hi, I am novice about loudspeakers project,also excuse my bad English.I would like to use a Moncor SP 90 in bass reflex + Monacor DT 101 SK .I calculated 134 liters box ,with F3 at 28 Hz.Iam not sure if the calculation is correct.Please can you help me ?
many thanks
Regards
 
that is not a good driver for this application. you can tune it low, but the limited xmax and xmech say it won't give you a lot of bass. There are way better arround. And that tweeter won't reach low enough to meet the woofer.

If you want a better combo that is cheap and easy to work with, use the Dayton RS180 woofer and the SB26ADC tweeter and cross at 1500 to 2000Hz. Both drivers can be bought (i suppose you're in Italy) here in this dutch (EU) webshop: SoundImports: Zelfbouw (DIY) audio componenten en accessoires - SoundImports

For 220 or so you got a very good combo to experiment with. If it sounds bad it won't be the drivers. They are not the best, but very high quality for their price i think. The woofer can be tuned to 30Hz in a reflex and still goes high enough to meet the tweeter arround that region with a 2nd order or higher crossover.

And other options exist also, many kits arround are at least worth studying to learn about that. Maybe for a first build, a kit may be a better id even...
 
not always, this driver does it in a 35L box with a slotport of 200x20mm and 282mm long. It only works on half the power rated, but that is already with 30Hz at 99dB before going over xmax (so a pair at 102dB) which is louder than most will go in a hifi setting.

If you want a high power subbass that low or in a big hall, i agree, but not for normal listening levels.
 

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If you wish something more affordable, check Visaton W200S - 4ohm version.
Fs=29Hz
Qts=0,35
Vas=65lit

Assuming 0,5ohm series resistance in crossover and cables, Chebyshev alignment gives Vb=63lit , Fb=35,5Hz , F3=31Hz and maximum SPL=109dB at excursion limit Xlim=10mm
 
never trust those online calculators but use proven software like WinISD, Hornrsp, VirtuixCad, ... (actually, those three are the highest rated freeware ones down here)

Most of those online calculators are very basic and not precise at all. I don't know the one you use, but in general they can't be trusted. I used WinISD for this, and checked it in VirtuixCad with the same result as i'm using one of those in one of my own designs. I may publish the design when i've build it, but it's in ready to order the wood-phase.

And this driver was used in a smaller case (14L) by Jeff Bagsby (a very famous speaker designer) in his tango kits tuned flat until 55Hz (-2dB) and 40Hz F3. The tweeter is the now unavailble Dayton RS28A tweeter. No way you need 135L to get a flat response with the RS180-4. It's that speaker, that a friend have and i know, that inspired me to make a variation with a different tweeter (the SB26ADC).
 
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@ waxx Ok I thank you very much .35 liters is the max volume for this driver SP90 ?
Ps: please can you give me the dimension for a round port (diameter/length)


No, the sp90 does not work for what you want. It’s a lowmid driver, not fit for bass. The 35l is for the dayton. And that visaton is also ok for bass, but not to pair with a tweeter i think. Then you will need a mid driver in between