8 ohm cab question

[pglaser01]

Hi all,

Previously I was running a GK210mb combo into a GK410MBX cab.

[email protected] of power even for outdoor gigs. I blew a speaker in the combo, and wound up buying a PF500. I LOVE THE TONE. First gig with it went really well.

However I’m noticing at practice I’m cranking the midrange, and then switching the midrange selector more and more to high mids. This was at our guitarist house with my 410. I use an old 810e at a local rehearsal studio, but it’s not mine.

I’m starting to think my cab is underperforming me....if this cab is rated 400w at 8ohms....what do you think I’m really putting into it wattage wise from the PF500? Typically gain @11 o’clock. Bass at 9-10 o’clock at most. Mids @2-3 o’clock...lately I’ve been moving the midrange to 4th position...volume is around noon before the red light kicks in....compression is barely above OFF..

Thanks for any help!!!

 

[Old Garage-Bander]

You can't compute power output from knob positions. Noon (or 5) isn't half power. The only useful information the knobs give you, other than all the up or all the way down, is some approximation of where you had therm set the last time.

The cab being rated at 400 watts has no bearing on the amplifier output. The speaker rating tells you the thermal power limits for the voice coils.

Find the manual for your amp and see what it says for power output at 8 Ohms. That figure will be a number determined during testing or computed mathematically. It has no bearing on real world gigging. But it will tell you the rated output into that impedance.

The speakers/cab may very well be less sensitive/efficient, not all are built equally. Unfortunately, those numbers don't get batted around like other, less useful data.

The same setup in two different venues can be like night and day. If you just EQ the same everywhere, you might run into that. EQ is not a set it and forget it deal. You can use it to help adjust for room acoustics.

 

[BadExample]

Ignoring compression, distortion and limiting, power out is a product of input signal, preamp settings (gain and eq, plus volume if the preamp has that), and the master.

If the speaker died from over excursion, maybe rather than cranking the mids, you need to reduce the bass/LF. An HPF might be the answer, perhaps at least in part.

Did the speaker suddenly go silent or did it start to sound bad. If you still have the dead speaker, maybe measure the resistance across the terminals with nothing connected and see if it has a burned open voice coil. My guess is mechanical death. Can you see any cone damage? If not that doesn't mean it wasn't mechanical.

 

[pglaser01]

You can't compute power output from knob positions. Noon (or 5) isn't half power. The only useful information the knobs give you, other than all the up or all the way down, is some approximation of where you had therm set the last time.

The cab being rated at 400 watts has no bearing on the amplifier output. The speaker rating tells you the thermal power limits for the voice coils.

Find the manual for your amp and see what it says for power output at 8 Ohms. That figure will be a number determined during testing or computed mathematically. It has no bearing on real world gigging. But it will tell you the rated output into that impedance.

The speakers/cab may very well be less sensitive/efficient, not all are built equally. Unfortunately, those numbers don't get batted around like other, less useful data.

The same setup in two different venues can be like night and day. If you just EQ the same everywhere, you might run into that. EQ is not a set it and forget it deal. You can use it to help adjust for room acoustics.

Yeah that’s a good point....in reality I should have known that prior to posting, but it was just so weird lately how trebly I’m making myself compared to my previous setup I’m troubleshooting

 

[BadExample]

Try cutting the offending frequencies.

 

[Old Garage-Bander]

Yeah that’s a good point....in reality I should have known that prior to posting, but it was just so weird lately how trebly I’m making myself compared to my previous setup I’m troubleshooting

You always need to adjust for current conditions, whatever they may be.

 

[Downunderwonder]

Yeah that’s a good point....in reality I should have known that prior to posting, but it was just so weird lately how trebly I’m making myself compared to my previous setup I’m troubleshooting

Treble by ear or treble by knob position?

 

[pglaser01]

Treble by ear or treble by knob position?

By knob position more so. I’m sure if I was standing another 30 feet from my cab it would be terrible sounding.

 

[Old Garage-Bander]

By knob position more so. I’m sure if I was standing another 30 feet from my cab it would be terrible sounding.

Why do you think it would sound worse?

 

[Downunderwonder]

By knob position more so. I’m sure if I was standing another 30 feet from my cab it would be terrible sounding.

That's what you get with 410 on the floor, craptastic dispersion of tone.

I am a 210 vertical stack believer!!

All you need to keep up with band on stage.

 

[pglaser01]

That's what you get with 410 on the floor, craptastic dispersion of tone.

I am a 210 vertical stack believer!!

All you need to keep up with band on stage.

Yeah. I’ve been spoiled by my 610 stack....I love the Ampeg and I’m considering trying to replace the speaker in the 210 combo, but actually convert it by removing the amp. That way I may be able to have an 8ohm 210, 8ohm 410, and 4ohm stack when needed.

 

[Gearhead17]

An easy fix is tilting the 410 towards your ears (2x4 underneath it on the front) or putting it on top of another cabinet so you can hear yourself better. My guess is that you are boosting the upper mids because the 410 is not spreading those frequencies towards your ears, mostly the back of your legs.

 

[Downunderwonder]

Yeah. I’ve been spoiled by my 610 stack....I love the Ampeg and I’m considering trying to replace the speaker in the 210 combo, but actually convert it by removing the amp. That way I may be able to have an 8ohm 210, 8ohm 410, and 4ohm stack when needed.

That's the manual on how to blow a 10 in one easy step.

You can only turn up until the 210 is complaining, at which point it feels like there is still a ton of headroom because the 410 is only loafing along with the other half of the amps output.

Read the vertical link.

 

[agedhorse]

Good example of how speakers fail in the field through no fault of their own, just misunderstanding how things work.

There are some good threads on speaker power handling here on TB. IMO, this would be a good time to read up.

 

[agedhorse]

That's what you get with 410 on the floor, craptastic dispersion of tone.

I am a 210 vertical stack believer!!

All you need to keep up with band on stage.

I disagree, there are plenty of examples of 410's that are a great choice for players other than yourself. There is absolutely nothing wrong with a 410 for most players.

 

[Stumbo]

An easy fix is tilting the 410 towards your ears (2x4 underneath it on the front) or putting it on top of another cabinet so you can hear yourself better. My guess is that you are boosting the upper mids because the 410 is not spreading those frequencies towards your ears, mostly the back of your legs.

This^

Get your cab closer to ear level both at rehearsal and your next gig.

 

[Stumbo]

I disagree, there are plenty of examples of 410's that are a great choice for players other than yourself. There is absolutely nothing wrong with a 410 for most players.

Which ones do you prefer?

 

[ThisBass]

Which ones do you prefer?

The question is not addresed to me but, personally I read this question asked as kinda trick question.
Honestly, the 410 format on its own provides some benefits that you can't get of from a different driver alignment. That's nothing but pure science and is independent of any brand or distinct sound design goals for the 410 driver alignment

 

[Tim Skaggs]

Hi all,
I’m starting to think my cab is underperforming me....if this cab is rated 400w at 8ohms....what do you think I’m really putting into it wattage wise from the PF500?

500 watts into a 4 ohm load will be around 250 watts into an 8 ohm load, probably slightly more, something like 275 watts, since the load is an impedance and not pure resistance.

 

[agedhorse]

Which ones do you prefer?

Probably over 50% of all reasonable quality 410's out there are plenty adequate. There's more negative comments being made out of this format than it deserves IMO. Vertically stacking does not automatically make for a better format.