Search found 98 matches

by Bill Fitzmaurice
06 Jul 2018, 22:15
Forum: Electronics
Topic: Adding an active sub or a 115 Cab?
Replies: 15
Views: 268

Re: Adding an active sub or a 115 Cab?

You need a crossover. Set it at 100hz. Everything lower will go to your sub and the rest to the full range box. That's what you do with PA cabs where the subs are optimized for use only below 100Hz and the tops are optimized for use only above 100Hz. Electric bass cabs aren't optimized for specific...
by Bill Fitzmaurice
29 Jun 2018, 01:43
Forum: Electronics
Topic: Adding an active sub or a 115 Cab?
Replies: 15
Views: 268

Re: Adding an active sub or a 115 Cab?

Chances are a 115 won't go any lower than your 212, unless it's a massive PA sub.
by Bill Fitzmaurice
28 Jun 2018, 02:17
Forum: Electronics
Topic: Adding an active sub or a 115 Cab?
Replies: 15
Views: 268

Re: Adding an active sub or a 115 Cab?

It's a common logic, but flawed. The power density of the signal drops by 3dB, ie., it's halved, with each octave increase in frequency, so adding a sub to assist the 212 from 40-100Hz won't help the 212 at all above 100Hz. In a PA subs only assist the mains when the signal is low passed to the subs...
by Bill Fitzmaurice
28 Jun 2018, 01:10
Forum: Electronics
Topic: Adding an active sub or a 115 Cab?
Replies: 15
Views: 268

Re: Adding an active sub or a 115 Cab?

Chances are a 115 won't go any lower than your 212, unless it's a massive PA sub.
by Bill Fitzmaurice
07 May 2018, 11:36
Forum: Electronics
Topic: Bypassing the preamp on a bass amp?
Replies: 8
Views: 264

Re: Bypassing the preamp on a bass amp?

1. You can't hurt the power amp bypassing the pre.
2. A limiter is for the protection of the speakers, not the power amp.
by Bill Fitzmaurice
05 May 2018, 12:19
Forum: Electronics
Topic: Beyer Mic Pinouts Help Please
Replies: 24
Views: 541

Re: Beyer Mic Pinouts Help Please

That diagram is incorrect. Pin 1 is ground/shield, pin 2 is +signal, pin 3 is -signal.
by Bill Fitzmaurice
15 Apr 2018, 23:14
Forum: Electronics
Topic: Tweeter Swap Aguilar DB112
Replies: 3
Views: 210

Re: Tweeter Swap Aguilar DB112

Then you need to figure out if it has the same nominal impedance as the tweeter you want to replace. If it has, we are still in business because it means you can keep the existing crossover. Not necessarily. To get the same result you'd have to use a crossover with exactly the same topology. If one...
by Bill Fitzmaurice
04 Apr 2018, 21:59
Forum: Electronics
Topic: Neo 10 in speakers for a GK 210RBH??
Replies: 4
Views: 269

Re: Neo 10 in speakers for a GK 210RBH??

Petebass wrote:
04 Apr 2018, 20:01
I'd argue both these statements are incorrect. .
+1. There are a dozen or more factors which determine driver performance. Magnet material isn't one of them.
by Bill Fitzmaurice
26 Mar 2018, 21:57
Forum: Electronics
Topic: Interesting article about running a 4ohm amp at 2ohms
Replies: 10
Views: 501

Re: Interesting article about running a 4ohm amp at 2ohms

There's nothing special about 2.67 ohms, it's just what you get when you use three 8 ohm cabs or an 8 ohm and a 4 ohm cab. There are also some factual errors in that article. For instance, when you halve the impedance load you double the power at small signal levels, but not at full power. I won't b...
by Bill Fitzmaurice
26 Mar 2018, 11:39
Forum: Electronics
Topic: Interesting article about running a 4ohm amp at 2ohms
Replies: 10
Views: 501

Re: Interesting article about running a 4ohm amp at 2ohms

Nothing there I didn't learn in college more decades ago than I wish it was.
by Bill Fitzmaurice
26 Mar 2018, 08:36
Forum: Electronics
Topic: Interesting article about running a 4ohm amp at 2ohms
Replies: 10
Views: 501

Re: Interesting article about running a 4ohm amp at 2ohms

I guess they'd really freak out seeing my BMW speedometer that goes to 260 KPH. Aren't the bassplayers supposed to be the smart ones in the band? :rollno:
by Bill Fitzmaurice
25 Mar 2018, 23:36
Forum: Electronics
Topic: Interesting article about running a 4ohm amp at 2ohms
Replies: 10
Views: 501

Re: Interesting article about running a 4ohm amp at 2ohms

Amps are rated for a given minimum impedance load based on their current delivery capacity. As load impedance goes down current, and heat generated, goes up. You can run at a lower than recommended load impedance if the volume is kept down. You may have a problem at the recommended minimum impedance...
by Bill Fitzmaurice
24 Mar 2018, 23:29
Forum: Electronics
Topic: Question about bracing a vibrating cab
Replies: 50
Views: 1626

Re: Question about bracing a vibrating cab

I know it cuts too. It's where it cuts that's the problem. This chart shows the low frequency sensitivity of a generic 1x12 cab with three high pass configurations. https://billfitzmaurice.info/images/Filters/highpassing.jpg The green trace is no filter. The blue trace is what you have, a first orde...
by Bill Fitzmaurice
24 Mar 2018, 12:54
Forum: Electronics
Topic: Question about bracing a vibrating cab
Replies: 50
Views: 1626

Re: Question about bracing a vibrating cab

Bill, I get you're concerns re 30hz, but honestly that's well below where most of us play a lot of the time. I'm not concerned about 30Hz at all. My concern is that as a high pass filter a capacitor will be ineffective unless sized to have a corner frequency around 120Hz, and when that's the case y...