Single PA top rather than amp?

[Graham]

I've been using an Ampeg SGT DI pre-amp for home use, as I'm not in a gigging band at the moment. I really like the sound of this pedal and when I do get back to playing live I'd like to have an amp behind me, to just transparently make the pre-amp louder

 

If I swapped my amp for a single PA speaker as a FRFR, could I get enough volume to amplify my SGT pedal  instead of using a traditional amplifier?

 

My amp is a EBS TD650, into an EBS Neo 2x12, when I was gigging I rarely pushed the volume past 9-10 o'clock. Before the TD650, I had an HD350 and whilst I had to to turn the volume control further, it was rarely past 11 o'clock; I think I went to 1 o'clock once - outside with no PA support.

 

Would something like a QSC K12.2 give me enough volume to replace the head and 2x12, even with half number of speakers? Or is this a fools errand?

 

[Dan Dare]

You'll have to try it and see. A lot of preamp pedals do not produce enough output to drive a power amp directly. With that said, many PA speakers have mic-level inputs, so it could be fine.

[Bill Fitzmaurice]

The key word is 'top'. They're made to be used along with a subwoofer. Some are capable enough to replace a bass speaker, but by no means all, and short of trying them you have no way of knowing.

[Skybone]

You could always just plug the preamp pedal into the Effects Return of your amp, as it simply bypasses the amp's preamp and puts the signal into the power amp.

 

I use a POD Go into the Effects Return of an Ashdown combo, works for me.

[BigRedX]

2 hours ago, Skybone said:

You could always just plug the preamp pedal into the Effects Return of your amp, as it simply bypasses the amp's preamp and puts the signal into the power amp.

 

But then you still get the colouration of the speakers.

[Phil Starr]

9 hours ago, Graham said:

I've been using an Ampeg SGT DI pre-amp for home use, as I'm not in a gigging band at the moment. I really like the sound of this pedal and when I do get back to playing live I'd like to have an amp behind me, to just transparently make the pre-amp louder

 

If I swapped my amp for a single PA speaker as a FRFR, could I get enough volume to amplify my SGT pedal  instead of using a traditional amplifier?

 

My amp is a EBS TD650, into an EBS Neo 2x12, when I was gigging I rarely pushed the volume past 9-10 o'clock. Before the TD650, I had an HD350 and whilst I had to to turn the volume control further, it was rarely past 11 o'clock; I think I went to 1 o'clock once - outside with no PA support.

 

Would something like a QSC K12.2 give me enough volume to replace the head and 2x12, even with half number of speakers? Or is this a fools errand?

 

You will be fine, I used the K12-2 for a couple of years and they are widely used by a host of other FRFR fans and are widely recommended fot that use. They are built to last and have a decent bass driver but are also really well protected so you'd be hard pushed to overload them to the point of damage so that won't be a worry. The other recommendation would be to look at RCF tops, the 912 would be a decent bet and is £100 cheaper than the K12-2

 

One word of caution, they are designed to give a flat response on a pole, On the ground the bass frequencies will be lifted by 6db and they will sound muddy if you dont roll the bass back a bit. Be prepared to have to fiddle a bit to get that right

[jezzaboy]

As long as you buy a decent pa speaker you will be fine. I used a RCF 715 in a rock band and it was never short of bass or volume.

[Skybone]

14 hours ago, BigRedX said:

 

But then you still get the colouration of the speakers.

But then you get colouration from the preamp pedal, modelling speakers.

 

You could also save money by not buying more gear, and the hassle of selling old gear.

 

But of course, it was only a suggestion to try out.

[BigRedX]

1 hour ago, Skybone said:

But then you get colouration from the preamp pedal, modelling speakers.

 

The point I was trying to make is that with bass cabs you are stuck with the colouration they impose on your sound. At leat with modelling speakers you can pick some different ones. I've found that for the sort of bass tones I want speaker emulations simply don't work. The only one I still use is a guitar one that is tied to a a combo sound I quite like. In every other case I found that turning off the speaker emulation made my sound better.

[Chienmortbb]

Bill is correct, but of course some "tops" with DSP have a monitor setting or even provide a high impedance input suggesting that guitar/bass is allowed or even expected, but a "top" capable of handling a bass at volume, without a High Pass Filter is both expensive and rare.

 

I would use your Ampeg Pre-Amp pedal into a lightweight (compared to your EBS) head into a good cabinet.  I am not going to recommend any particular amp or cab, but the main difference between amps is the Pre-Amp. As you have the Ampeg, look for an amp with a good power output with the ability to bypass the front end and input to directly to the power amplifier. As for cabinet, look for n uncoloured cab (the colour is in the Pre-Amp).

 

The main thing about a PA top, such as the QSC 12.2 is that it has a decent crossover, compression driver and horn. Very few bass cabinets have this, so even those with tweeters are a significant compromise. Also avoid cabinets with adjustable tweeter level. This suggests a lack of confidence in the design. Your bass and preamp can reduce the treble, so why put an attenuator on the cabinet?

[Chienmortbb]

1 hour ago, BigRedX said:

 

The point I was trying to make is that with bass cabs you are stuck with the colouration they impose on your sound.

Of course, some bass cabinets are flat and have a full and have flat frequency response or transfer function, ideal for either modelled sounds or the traditional Head/Cab use. However, even those will sound different due to both the specifications of the drivers used and the design goals of the designer(s).

[Bill Fitzmaurice]

2 hours ago, Chienmortbb said:

 Your bass and preamp can reduce the treble, so why put an attenuator on the cabinet?

Because the average horn loaded high frequency driver has 10dB higher sensitivity than the average woofer attenuation by one means or another is a necessity. It can be with a variable LPad, or with a fixed value LPad, or with DSP. Yes, the bass and preamp can reduce the treble, but their frequency passbands don't necessarily line up with that of the tweeter. Besides, there's nothing wrong with tweeter attenuation, we've been doing it for a hundred years, so why not?

[Chienmortbb]

54 minutes ago, Bill Fitzmaurice said:

Besides, there's nothing wrong with tweeter attenuation, we've been doing it for a hundred years, so why not?

Because a user cannot know what effect she/he is having on the cabinet characteristics. Also, there are many things we did 50 years ago that we do not and would not do now. Indeed, Child labour in the UK was only really banned in 1944 when compulsory state education was introduced.

[Bill Fitzmaurice]

Don't make more of it than you should. All attenuation does is to turn down the tweeter. If a user can't figure that out they should stick to acoustic instruments. 😉

[stevie]

5 hours ago, Bill Fitzmaurice said:

Because the average horn loaded high frequency driver has 10dB higher sensitivity than the average woofer attenuation by one means or another is a necessity. It can be with a variable LPad, or with a fixed value LPad, or with DSP. Yes, the bass and preamp can reduce the treble, but their frequency passbands don't necessarily line up with that of the tweeter. Besides, there's nothing wrong with tweeter attenuation, we've been doing it for a hundred years, so why not?

 

John's not suggesting running high frequency drivers without any attentuation (obviously!). He's questioning the point of having an L-pad attenuator in the system at all. I had a three-way bass cab at one time with L-pads on the midrange driver and tweeter. I couldn't for the life of me figure out the best setting by ear and had to carry out measurements to find out what was happening. I ended up with something like twenty-to on the mids and quarter past on the HF. Many people assume that 12 o'clock is flat, but it rarely is.

 

IMO, the best solution is for the manufacturer to set a fixed attentuation level that balances the bass/mid and HF.

Edited 9 hours ago by stevie

[Stub Mandrel]

2 hours ago, stevie said:

Many people assume that 12 o'clock is flat, but it rarely is.

 

Many people assume that flat sounds best, but it rarely does. 😁