# Box info needed for hertz HX250D. Sq system



## Liblikas (Nov 25, 2008)

I need some advice on box for that element. Im looking for Sq box but i don't know how big box i should make and vented or closed. Thinking about closed. If vented then what size port. Its 10" element. I will but 2 of those in my mk2 golf. And i will make 2 boxes for them. I listen to every kind of music, mostly dnb and hip-hop if that matters. I just need the box cubage(if ported then port size too) so i can calculate the size myself.
Info on the element:
Size: 250mm(10")
(MAX/RMS): 900W/450W
impedance: 4+4 Ohm
frequency : 34-800 Hz
sensitive: 88dB
T/S parameters:
D - 210 mm
Xmax - 14 mm
Re - 5,8 Ohm
Fs - 34 Hz
Le - 7,27 [email protected]
Vas - 20,54 lit
Mms - 176,9 gr
Cms - 0,12 mm/N
BL - 23,34 T-M
Qts - 0,37
Qes - 0,39
Qms - 6,8
Spl - 88 dB


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## Pat @ Pitt Soundworks (Nov 14, 2008)

*Re: Box info needed for hertz HX250D. Sq system (Liblikas)*

EBP is 87.18. 
EBP > 50, go vented
EBP < 50, go sealed
EBP 45-55, either way.
Voice coil is 2.56 inches. xmax is 14mm and xmech is 23mm both ways. 
It's really quite odd that they chose a such a really large voice coil, strong motor, yet limited linear excursion to 7mm one-way. I've used dedicated midbass that have more displacement than this sub.
LE of 7.27 means it's not going to be very "musical". It's going to be slow in transient music. 
Really this driver makes absolutely no sense to me. Regardless, without modeling it up, I would say it would probably do good in a small ported .75 cubic feet enclosure tuned to 32hz. or a sixth order bandpass, .5 cu front chamber @ 30hz, .4 cu rear chamber @ 65hz. 
Lets see how she models:








For ported, use a highpass @ 32hz, lowpass @ 80hz.
For bandpass, highpass @20hz, lowpass (none)
Both boxes will allow more power than the sub will be able to thermally handle.
Group delay sucks on both boxes, but that's the nature of the beast - due mostly to the high inductance (LE). I would go with sixth order bandpass. It's slightly lower group delay and ability to filter out harmonic distortion gives it the edge.


_Modified by Pat @ Pitt Soundworks at 9:02 PM 4-2-2010_


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## Liblikas (Nov 25, 2008)

But is Alpine Type-R 10" swr-1042d better than this Hertz? If so, then i will probably go for type-r.
Size: 250mm(10")
(MAX/RMS): 1500W/500W
impedance: 4+4 Ohm
frequency : 26-600 Hz
sensitive: 83dB
T/S parameters:
Xmax - 18.2 mm
Re - 3,94 ohm+3,94 Ohm(thats what is says on the paper that i got with my 12" R)
Fs - 33 Hz
Le - 3,94 [email protected]
Vas - 20 lit(0,71ft3)
Qts - 0,53
Qes - 0,57
Qms - 7,92
Spl - 83 dB


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## Pat @ Pitt Soundworks (Nov 14, 2008)

*FV-QR*

Inductance is better. BL and CMS curves are better. Voice coil is SMALLER. XMAX and XMECH are better (19.4mm and 32.5mm one way). Although I THINK it's an overhung motor design (blah) while the hertz is probably underhung.
Either way, I feel it's a much better design. .75 cu ft ported at 34hz, with a subsonic filter at 26 hz, will put a smile on your face while taking enough power to block the voice coil apart before failing mechanically. 


_Modified by Pat @ Pitt Soundworks at 10:48 AM 4-3-2010_


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## Liblikas (Nov 25, 2008)

Ty for the help


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