[toshvan]

Hello ppl,


I first posted this at Parts-Express forum (since DCS380-4 is sold by their web-shop) but somebody there suggested I should ask the experienced ppl here.



I want to use Dayton DCS380-4 15" subwoofer driver in Tuba HT folded horn cabinet. I will use Foster wf-100k Plate Amplifier I bought from Jack Hidley's NHT surplus sale. (115W into 4ohms, 80W into 8ohms. 4th order (24dB/octave) low pass adjustable from 50-200Hz. 0-180 degree phase switch)


The thing is that the amp has a 3rd order (18dB/octave) high pass filter set at 29Hz with a Q of 0.707 built in. Tuba HT cabinet is tuned to go very low so I think I should modify the high pass filter to whatever the Dayton DCS380-4 can safely work with.

Dayton DCS380-4 specifications: Power handling: 250 watts RMS/350 watts max VCdia: 2" Le: 2.32 mH Impedance: 4 ohms Re: 3.1 ohms Frequency range: 20-500 Hz Fs: 23 Hz SPL: 92 dB 2.83V/1m, 89 dB 1W/1m Vas: 8.26 cu. ft. Qms: 3.46 Qes: 0.59 Qts: 0.50 Xmax: 8.4 mm


Does somebody here have experience with DCS380-4? Specs say 20-500 Hz, so should I go for 20Hz cutoff frequency?

Also should I modify the 3rd order (18dB/octave, HP response with a Q of 0.707) to some other value more appropriate to the combination of the Dayton DCS380-4 and Tuba HT cabinet? (I'm not sure I understand the Q parameter)



I know I'm asking too specific of a question here. I'm kind of a noob for audio and electronics, and many things are mixed up in my head right now from reading too much in too short of a time... I would be grateful for any help on this.




P.S. I would have linked pages with specifications for the driver, amp and Tuba HT cabinet, but I'm unable to post links until I make at least 3 posts (and this is my first one

)

 

[toshvan]

I've decided to hi-pass my amp @15Hz.

Bill Fitzmaurice, the designer of this basshorn, was kind to explain that THT does not require a HP filter, as it reaches maximum excursion at 22Hz, dropping below that. Since my amp already have high pass filter set at 29Hz, I was contemplating whether to remove it altogether. What finally decided me was maxmercy's post on this subject in myn's Tuba HT Review:

Quote:
I have never found any power compression with my THT, but I have never run a sweep through it at higher than 15-20V (45-80 Watts). No need to. Even with it's small rear chamber, You can reach excursion/distortion limits at low voltages at frequencies below 15Hz.

Hopefully this might help somebody else in similar situation...