Hi guys - I'm taking the electric bass up again in my dotage and want to build a couple of identical cabinets which I can clip together on stage but lug about seperately. I'll be driving with a Hartke 2000 amp (200w into 4ohm) and I've been looking at using 2 Max Pentivent 1030s, one for each box. They run up to 2KHz, which is plenty for me.
fs: 19hz
qts: 0.35
qes: .37
qms 3.6
Vas: 130 litres
Z:4 ohm
DCR: 2.9
xmax(one way) : +/- 4mm
pe: 125W
sd (approx): 360 sq.cm.
Sensitivity 90db 1@1
Using a sealed box I don't seem to be able to get f3 below 48Hz, but I'm told that a ported box is going to overdrive the speaker excursion at 30-40Hz. Any solution to this? What's the way to get the smallest box possible but still have f3 below 30? Or am I just wanting the impossible?
Thanks, labougie.
fs: 19hz
qts: 0.35
qes: .37
qms 3.6
Vas: 130 litres
Z:4 ohm
DCR: 2.9
xmax(one way) : +/- 4mm
pe: 125W
sd (approx): 360 sq.cm.
Sensitivity 90db 1@1
Using a sealed box I don't seem to be able to get f3 below 48Hz, but I'm told that a ported box is going to overdrive the speaker excursion at 30-40Hz. Any solution to this? What's the way to get the smallest box possible but still have f3 below 30? Or am I just wanting the impossible?
Thanks, labougie.
Small, going low and being loud aren't impossible things per se but the combination of all of the three definitely is.
An instrument-speaker going down to 48 Hz @ -3dB isn't that bad either. Did you have a look at some popular bass speakers, many of those aren't even going down to below 60 Hz @ -3 dB (they definitely trade efficiency and transportability for low-end extension).
The thing that would bother me more is the low efficiency of your driver unless you are going to play at low volumes only.
Regards
Charles
An instrument-speaker going down to 48 Hz @ -3dB isn't that bad either. Did you have a look at some popular bass speakers, many of those aren't even going down to below 60 Hz @ -3 dB (they definitely trade efficiency and transportability for low-end extension).
The thing that would bother me more is the low efficiency of your driver unless you are going to play at low volumes only.
Regards
Charles
Who told you that about a vented box? As the tuning will be in the 30-40Hz region you will actually get minimum cone movement in that region. Unloading will take place below the tuning frequency, but that probably won't be so bad for you and can be protected against with a filter.
Phase_accurate - I note your concern about speaker efficiency. Am I correct in saying if there's 90db @ 1 watt and I have 7 power-doublings available, that should give me a little less than 111 (90+21)db at the speaker's RMS rating of 125 watts? How does the fact that this is one of two speakers being so driven affect the db? I could live with 110 as a maximum if it wouldn't strain two speakers.
Richie00boy - I'm getting this information from Bass Box, which is telling me that if I want the flattest response, I have a 12mm excursion to deal with at between 30 and 40 Hz. This, by the way, is with box tuning at around 22. If I tune higher, the excursion is fine, but I wind up with a +2 db hump between 40 and 50, flattening off at 110. Is that such a bad thing? I suppose I could EQ it out.
Thanks for the input.
Richie00boy - I'm getting this information from Bass Box, which is telling me that if I want the flattest response, I have a 12mm excursion to deal with at between 30 and 40 Hz. This, by the way, is with box tuning at around 22. If I tune higher, the excursion is fine, but I wind up with a +2 db hump between 40 and 50, flattening off at 110. Is that such a bad thing? I suppose I could EQ it out.
Thanks for the input.
If an SPL around 110 dB is really enough for you then you can give it a try. But take care and don't use two of this 4 ohm drivers in parallel.
Regards
Charles
Regards
Charles
110db (or 113db with two cabinets) should be plenty for me - it's a country band and bar-type venues. The impedance thing is sorted too - I plan to use a 150w/side 4ohm power amp and drive two cabinets independently (Fishman Platinum Bass as preamp).
The only query left is the 2db hump starting at the box tuning frequency (30-40) and settling down again at 110 or so. Is this going to cause muddiness problems, or can I just eq it out?
Thanks for the input, David.
The only query left is the 2db hump starting at the box tuning frequency (30-40) and settling down again at 110 or so. Is this going to cause muddiness problems, or can I just eq it out?
Thanks for the input, David.
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