Magic item creation, need help

[Atilary]

I took a shot at making magic item, and have noe idea how to calculate the cost. I just read the tables and got confused. Cana nyone give me any ideas here? Heres the item...

Horn of Resonance: This crafted horn appears to be a normal blowing horn until someone speaks the command word and blows upon it. When activated, the horn causes a fear affect in a 30’ radius. Any enemies within the radius must make a Will save DC 16 or be panicked for 4 rounds. Any character that passes the save is still shaken for as many rounds. When the horn is blown, it can be heard up to three miles away, after which the sound is inaudible. The fear affect can only be used once per day, but the horn will always be audible for three miles.
Moderate necronomacy; CL 4th; Craft Wondrous Item; fear, whispering wind; Price 30,000 gp; Weight 2 lb.

I calculated the price as 4(lvel spell) x 4(caster lvl) x 750 x 2(1 min/level) = 24000 and 2(lvel spell) x 4(caster lvl) x 750 = 6000 (added together they are 30000 gp).

Anyone give me any help and tell exactly how to do this?

 

[GuardianLurker]

3.0 calculation: 4 (Fear; 4th level spell) x 7 (min caster level) x 1800 (command word) / 5 (1 charge per day) + 2 (Whispering Wind; 2nd) x 3 (Caster level) x 2000 (use activated), entire thing doubled since you don't use a chakra =

(((4x7x1800) /5) + (2x3x2000))x2 = ((50400/5) + 12000)x2 = (10080 + 12000)x2 = 44160

3.5 Calculation:
((((4x7x1800)/5)x2)+(2x3x2000))x2 =
((10080x2)+12000)x2 = 32160x2 = 64320

 

[Atilary]

Thats really not that far off from what i got my first attempt (64000 or thereabouts) but I thought it was incredibly high for what the item did. Does anyone agree? Oh, im using 3.5 rules too.

 

[GuardianLurker]

It probably is way overpriced - given that a Greater Horn of Blasting (using a 7th or 8th level spell) is 70K.

I'd probably lop the cost in half - call it 32K. Your rock bottom minimum is 20K (the cost of the fear effect). It's up to you and your GM to determine how much the "hear for 3 miles" is worth.