Kick sounds great in my monitors but horrible out front

[aw_dee_o]

I've performed the above mentioned mods to dozens of local Peavey low frequency cabs. Every single owner that has heard & experienced the difference was thoroughly impressed. Many of the folks that i've done this for came to me after both hearing / experiencing the differences for themselves via hearing previous cabinet mods that i've done.

 

I'm not worried about "skin effect" on subs / low frequency drivers, as frequencies this low travel through the entire conductor. As such, a 12 gauge solid core wire actually has lower series resistance than a 12 gauge stranded conductor. Having said that, it's not enough of a difference that i would lose sleep over it, hence my comments about stranded being slightly more reliable on the road.

 

Outside of that, i stand behind all of the work that i do. As such, i have to make sure that something is rugged enough to take quite a bit of abuse, otherwise i'm giving away free warranty labour and losing time & money that could be better invested elsewhere.

 

As it is, i've got three Peavey 3620 cabinets that locals dropped off to take care of very shortly. When i'm done with them, they'll actually reproduce 40 Hz with authority rather than just rumble and try to fake it. The fact that i basically charge just for parts is something that i chose to do in helping people out while improving their sound. I like helping people AND i like better sound. In effect, everyone involved wins. They just better not be in a hurry for their stuff, cuz working free typically means working slow too Sean

 

[soul-x]

I've performed the above mentioned mods to dozens of local Peavey low frequency cabs. Every single owner that has heard & experienced the difference was thoroughly impressed. Many of the folks that i've done this for came to me after both hearing / experiencing the differences for themselves via hearing previous cabinet mods that i've done. I'm not worried about "skin effect" on subs / low frequency drivers, as frequencies this low travel through the entire conductor. As such, a 12 gauge solid core wire actually has lower series resistance than a 12 gauge stranded conductor. Having said that, it's not enough of a difference that i would lose sleep over it, hence my comments about stranded being slightly more reliable on the road. Outside of that, i stand behind all of the work that i do. As such, i have to make sure that something is rugged enough to take quite a bit of abuse, otherwise i'm giving away free warranty labour and losing time & money that could be better invested elsewhere. As it is, i've got three Peavey 3620 cabinets that locals dropped off to take care of very shortly. When i'm done with them, they'll actually reproduce 40 Hz with authority rather than just rumble and try to fake it. The fact that i basically charge just for parts is something that i chose to do in helping people out while improving their sound. I like helping people AND i like better sound. In effect, everyone involved wins. They just better not be in a hurry for their stuff, cuz working free typically means working slow too Sean >

 

If I remember correctly the 3620 is a bass guitar cabinet with two 1801 BW drivers in an undersized ported enclosure (it also has 2 scorpion 10s in a sealed chamber).

 

What can possibly do to make it produce 40hz in any meaningful capacity? That's below the cabinet tuning.

[aw_dee_o]

By altering the Q at resonance and changing the frequency of resonance, it is quite possible to arrive at many different alignments and output levels for a given driver / cabinet combo.

 

On top of that, one should realize that vents aren't always the best choice for any given application. In terms of actual sound quality and "control", vents aren't all that great. In effect, you end up with two uncontrolled resonances ( driver and vent ), which is actually TWO points of uncontrolled oscillation. You can't get something for nothing and that extra quantity of output from the vents sacrifices quality of control and damping.

 

Vents also roll off at 24 dB/ octave below tuning, which means they produce maximum output and then drop like a rock. Any signal below the resonance of the vent results in increased distortion, excessive excursion and reduced power handling.

 

If you look at most vented systems, the impedance peak at the points of resonance are VERY high i.e. sometimes 80 ohms or more. How much power do you think your solid state amp is going to deliver into 80+ ohms??? Even if it is rated at 200 watts @ 8 ohms, you now have less than 25 watts available at the points of resonance. On top of that, this is where you need it most, as the driver is going into self-oscillation. That oscillation is the reason behind the resonance !!!

 

Why everyone tries to avoid resonances and oscillation EVERYWHERE else in the signal path but then purposely tries to insert them into the bass region is beyond me. Think about it.....

 

On the other hand, a sealed cabinet with varying levels of fill and fill material ( fiberglass, poly, etc.. ) will only produce one peak at resonance. That peak can easily be controlled by playing with the type ( fiberglass, poly, etc... ) density ( quantity of specific types of fill ) and placement of fill within the cabinet. When doing this, there's less of a rise in impedance at resonance, so power transfer is improved. This results in better control, definition, tone and extension.

 

On top of that, sealed cabinets roll off at only 12 db / octave. This means that two equivalent cabinets tuned for a max output at 80 Hz will have the vent -12 dB down at 60 Hz whereas the sealed cabinet will be down -12 dB at 40 Hz. In effect, you get another half octave of extension with better control for slightly less output at higher frequencies by going with a sealed cabinet. Slightly less output isn't a big deal when most bass rigs have HUNDREDS of watts available, unlike guitars that "might" have 100 - 150 or so.

 

One more thing. Since you're getting more extension out of the sealed cabinet naturally, you now don't need as much EQ to bring up the extreme bottom end. This reduces the load on your power amps, increasing dynamic headroom within the system. There's also less thermal stress on the driver since it doesn't have to displace all of the extra heat that goes along with massive EQ'ing.

 

Unfortunately though, most people want "more, more, more", not "better quality". This is why vents are FAR more common than sealed designs. This is not only true of Pro Sound gear, but also home and car audio too.

 

If one wants maximum output and extension, the best way to achieve this is to horn load the front of the driver and use a passive radiator on the back wave of the driver. The horn loading gives you great sensitivity and the passive offers the most bass "weight" down low. Only problem is, passive radiator designs are the slowest in transient response, resulting in increased ringing and a lack of definition. Like i said earlier, you can't get something for nothing. That extra quantity once again costs you quality of sound.

 

For "Pro Sound" though, this might not be a problem since most people will not notice anything other than the sound from the much louder frontal wave of the horn. While the increased ringing at low frequencies might not be a big problem, the added bottom end extension might be a problem. That is, with increased output at very low frequencies, the system may be exciting more room nodes. Rather than sounding impressively deep and powerful, the system may now sound "slow, bloated and thick" due to all of the standing waves being generated.

 

If you want to learn about speaker design, check out Vance Dickason's Loudspeaker Design Cookbook. If you want to learn about room loading and acoustics, check out books by F. Alton Everest. Sean

 

PS... The above figures are strictly generalizations and not meant to explain any specific mods that i do, either to the 3620's or any other cabinet. They were just meant as examples.

[soul-x]

PS... The above figures are strictly generalizations and not meant to explain any specific mods that i do, either to the 3620's or any other cabinet. They were just meant as examples.

 

 

So are you planning on converting the 3620 into a sealed cabinet?

 

How are you planning on getting a useful 40 hz out of a cabinet/driver combo that is too small for it?

[agedhorse]

Wishful thinking.

 

I have modeled this driver and it just ain't gonna happen (sealed enclosure or otherwise), certainly not without some seriously active eq correcting the response and even then, the max SPL will be so derated at 40Hz as to be virtually unuseable.

 

Simulate this and see how far below the 3dB down point you end up.

[burdizzos]

 

We should start with getting your rig optimized and then move on to getting a decent sound for your drums. Time permitting, we can work on the rest of the instrutments. Send me a PM letting me know what your schedule looks like and we can coordinate from there. Oh yeah, please let me know what mixer you are using now. Thanks

 

 

 

If you guys do some kind of lab, let me know when it is. I'd like to get in on it so I can learn more about what I'm doing with my own rig. I'll bring the drinks.

[blueride]

I have been using similar subs (Yamaha 18's) and experiencing the same weak kick. Solution was to couple them by placing both subs either centerstage or stacked on one side. Huge difference.

Depending on the acoustics of the room, subs have a tendency to cancel each out unless they are placed together.

[soul-x]

 

Wishful thinking. I have modeled this driver and it just ain't gonna happen (sealed enclosure or otherwise), certainly not without some seriously active eq correcting the response and even then, the max SPL will be so derated at 40Hz as to be virtually unuseable. Simulate this and see how far below the 3dB down point you end up.

 

 

That's why I was asking.

 

Aw_dee_o indicates he can make it happen with installation of some 'parts'.

 

This forum is a place I come to pick up meaningful information. If there are 'parts' to get real output below a cabinet/driver's rolloff, I'm all ears.

[Zeromus-X]

 

If you guys do some kind of lab, let me know when it is. I'd like to get in on it so I can learn more about what I'm doing with my own rig. I'll bring the drinks.

 

 

Will let you know.

 

Square, I'll be PMing you after work today as soon as I know what's up. The mixer is a PV20, one of the new ones. Our old one (the EV) decided it didn't want to power up anymore, and rather than spend the money on it, the bassist decided to just get a new one.

[soul-x]

Oh and to address Zero, I'd drop the x-over frequency down to around 100 hz

[mshifflett]

 

Imagine you're standing outside a loud concert venue listening to a kick drum (and imagine the bass guitar isn't playing!). There's a lot of bass, but none of it is kicking you in the chest, it's not defined, it almost sounds like a low rumble. You can tell it's there, it's just not musically appealing.

 

 

A compressor will help tighten this up a bit.

[agedhorse]

A compressor may make things worse too.

 

My first attempt to work this out would be to gate the kick, w/ gain reduction of about 12-18dB, fairly quick attack time and a release time of maybe 100mSec to start, then add a compressor after the gate but being careful not to overdo it with compression.

 

The problem with compression without gating first is that the signal path gain will need to be higher in order to compress and that's what increases the average SPL and modifies the peak to average ratio of the kick signal. If you don't compress, the increased gain may muddy things up causing some ringing and undefined overtones of the rest of the sound on stage that will ultimately vibrate the drum head.

[Zeromus-X]

Wow, someone dug this up. Guess I'll update.

 

So far I've made the following changes:

 

1. Moved the kick mic as per drumstix' suggestion. I've got it sitting about an inch inside one of the two holes on the front head. I've also replaced the front kick head since it was stock. This alone made a pretty big difference. Interestingly, when I mic it this way, both of my kick pedal beaters make a pretty stunningly different tone when I hit the head... but that's irrelavent to this topic.

 

2. Since the XTi that I'm using now has a delay feature built in, I've tried messing with that, and didn't notice any appreciable difference (except that when playing on crappy e-drums with a huge delay on the poweramp, I have no way of playing in time with the band!).

 

3. Checked the phase of the drum sub and it's in phase with the rest of the PA's subs, which are in phase with each other. I don't know if the drum sub and PA subs being in phase is a good thing or not, since they're not lined up or anything. Maybe reversing it would help, but:

 

4. Eliminated the drum sub variable altogether by getting IEMs.

 

Running the PA without the drum monitors gives basically the same effect, no real "definition". I'm sure gating and compressing the kick would make a pretty big difference -- when we play larger venues with installed systems, it pretty much always sounds better. Of course, they're using a better PA than us, too. Catch 22. However, people haven't been commenting "hey man, your kick sucks!" at shows, so maybe I'm just being too picky about it.

 

Haven't forgotten about you Square, just haven't found time to set this stuff up!

[Square]

 

Haven't forgotten about you Square, just haven't found time to set this stuff up!

 

 

No worries. I will have a good bit of free time after July 4th through August on the weekends. Let me know when you are ready.

[Mogwix]

 

We've got a song or two where the singer plays drums so I can see what it sounds like out front, and it still sounds like a garage band is playing to me, not a "professional" club/bar band.

 

Is your singer an awful drummer? I know with my kit, when I play it it sounds magic, but when my singer plays it, it sounds like I spent $10 on the whole kit.

 

Just askin' 'cause y'know, every drummer is different. You and him may sound COMPLETELY different given the same kit.

[Mogwix]

 

If one wants maximum output and extension, the best way to achieve this is to horn load the front of the driver and use a passive radiator on the back wave of the driver. The horn loading gives you great sensitivity and the passive offers the most bass "weight" down low. Only problem is, passive radiator designs are the slowest in transient response, resulting in increased ringing and a lack of definition. Like i said earlier, you can't get something for nothing. That extra quantity once again costs you quality of sound.

 

Also note that folded-horn and horn-loaded subs are insanely big and heavy.

[Craig Vecchione]

 

Who needs output below 50 or 40hz? As I see it, being dead flat to 20hz is ridiculous at best and completely unnecessary. The 40hz HPF filters on my amps are always on, for the sake of my drivers but also to clean off the mud. You're still trying to feed thousands of watts into a frequency range that doesn't exactly matter. 40hz HPF and you've suddenly got way more headroom from your amps to focus on the range that does matter. I'm not sure if it's really pertinent to note, but I always felt that at high power, the vents moved a lot of air in and out of the enclosure which helped disperse a lot of heat. Also note that folded-horn and horn-loaded subs are insanely big and heavy.

 

 

It's just more audiophile BS. There's likely to be no source material that low to begin with unless there's a key synth in the band.