Running Two Speakers?

Douglas Schuch · From: Valencia, Philippines

What are the pros and cons of various methods of running two speakers?

Methods I know of:

STEREO: using a Stereo Steel, or some sort of stereo processor in the chain.

MONO: running two speakers from the same output. I've heard that if you spread them out, they create some weird effects in the areas where the two signals overlap - reinforcing and cancelling each other to some extend, depending on exactly where the listener is. I've also heard this can be minimized by using different speakers (size, brand, etc). True?

MONO, OUT OF PHASE: I've read about people running two speakers in mono, but with one out of phase (I.E, the speaker wires reversed on one speaker). I've heard this can sound really good, but have you tried it? Is it that much different than "MONO", above?

STACKED: Basically creating the same type of setup a Twin has - a single source, even though two speakers, due to their proximity. This does not solve the problem of covering a wide area, as a stereo setup with a speaker on each side of the stage would do.

I think "stereo", like a Stereo Steel, is not creating two completely distinct channels, as you can play through one channel and it sounds fine. So I'm guessing just introducing enough variation in the two channels to avoid any cancellation issues? Do I have this right?

I have a Mono Steel at the moment (a Stereo Steel with one blown power amp). Parts are working their way towards me - hopefully will be back to stereo-capable soon, but pondering options if I can't repair it.

Thanks to all who reply for educating me!
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Scott Denniston · From: Hahns Peak, Colorado, USA

I like the sound of using two amps but not really stereo. One with fx (reverb & delay) the other completely clean. When I did it this way I'd stack them. The reason I did this was I could hear something being robbed from the clean punch or whatever by the fx no matter which way I ran the fx--before the amp or through a loop. So I'd have an fx amp and a clean punchy amp blended. The little I play out these days I don't lug that much stuff though.

Jerry Overstreet · From: Louisville Ky

Stereo, as in the Stereo Steel with a l and r channel, is accomplished by the off-board stereo effects units. Input to the fx unit is basically 2 separate mono inputs but can be tweaked with effects, eq and vol to create 2 different sounds.

Stereo fx units, with l & r inputs and outputs, take these basic mono inputs and output a stereo image in the effects blocks by using different effects or different values of effects and routing, so the stereo effect is done by the fx unit and can be panned or mixed somewhat also with the SS controls.

In the earlier days of what we called stereo using 2 combo amps was as described above by the wet/dry method. One amp was eq-ed and set without any effects and all the effects applied to amp #2. By mixing the volumes of these 2 amps, a stereo image is created by having the dry amp on one side and the wet amp on the other. Using amps of dissimilar design also enhanced the stereo effect.

Using an extension speaker with one combo amp will generally just give you more sound. On stages, a separate extension speaker can be directed toward the other side of the stage for dispersing the sound to other musicians.

FWIW, I'm using rack style stereo rigs since the 90's. It's my favorite. I have a big rig at the jam barn that still blows me away and a smaller one I can carry with me. For small and cramped stages, I still have a NV400 I can use if I have to.

Downside is many stages are cramped and you can't spread the speakers out enough to get good dispersion and the stereo effect may diminish as it travels out toward the back of the room, but it's heavenly from where I sit. It has to sound good to me too, ya know?

I know they have fallen out of favor in recent years partly due to lack of mfg. support and partly due to old guys not wanting to tote so much gear. Other players just like to keep things simple.

I think the era when Jeff Newman set up the Peavey lightweight rack amps with the "Fex" units with all the steel presets and 2 speakers was one of the most musical. Lots of players signed on for these configured rigs. All they had to do was turn on the switches. The selections of steel sounds were there just by scrolling the presets.

This took the confusion out of programming stereo rigs for a lot of players and answered a lot of equipment questions as they were playing the same rigs as the pros.

As equipment evolves and hopefully gets better, some players are quite content with the combo amps and stomps of the day, but I'd like to see the circle come back around to these stereo rack rigs if the mfgs. would support it again. JMO.

Godfrey Arthur · From: 3rd Rock

Stereo on stage is basically useless for the audience. It only works in close proximity to the player using the system. Not unless you turn the amps up until the sound travels into the audience will the sound be heard but IN STEREO is a big hit and miss because only the people in the center of the two speakers will receive a stereo sound. Everyone on either side of that select few will get varied degrees of stereo.

And if there is a PA involved, all the sound bleeding into the mics on stage will water down the stereo effect of let's say a chorus or phaser. YMMV.

Two speakers on stage end up being "monitors" so that people on the other side (players and audience) can hear you. Or more monitors facing you so you can hear yourself in a wider dispersal of sound.

The better option is stereo through the PA but that is limited depending on where the listener is in between the left and right speakers for them to get a stereo sound. Can't hear stereo if you're closer to one side of the stereo field.

Mixing phase on speakers, even if it changes the sound, how will that affect the sound of the band to the listener?

Unless your gear is mic'd will there be a noticeable effect but then it would be complex mixing connections and mixer phase switch settings involved.

Reversing phase on let's say a drum monitor amp/speaker that is aimed at the drummer's back so he can hear his drums is used when micing drums and the phase is reversed so that the kick drum mic and the amp speaker signal cancel each other out to reduce feedback by being out of phase with each other.

What happens is there is less of a bassy tone.

The positive voltage of the kik drum mic and the reversed signal of the kik drum mic going into the monitor amp cancel frequencies out. When the kik drum pushes the head outward away from the drummer, the monitor speaker is travelling backwards away from the drummer as well, when the two (kik drum head mic and monitor amp speaker) are out of phase with each other.

Here's a video by Dave Rat. It may not answer your question directly, but it may give one insight to phase reversals with speakers using show and tell.

https://www.youtube.com/watch?v=vOuBN8jw2Qk

It all depends on what you're trying to achieve, how much gear you have and how large a venue you're playing.

There are stereo combo amps out that will give a stereo effect to you the player but realistically it will have no effect for the audience.

If you're trying to fill a large space with an audience, a PA is the better way to go rather than cart around lots of gear. And then if the stage is huge, monitors so each player can hear everything, or not.

With your blown stereo amp, getting two speakers in phase and of the correct impedance to match the one side you have left is more important than the rest in order to make best use of your crippled stereo amp.

If you have a PA then send a line from your rig to that to add to the dispersal.

If your amp was used overseas and now you're using it on Philippine grid, I would invest in a voltage regulator to clean up the power somewhat. Don't plug it into the grid directly.

An AVR although it introduces some noise is better than no regulation at all and is preferred over a mere step-down transformer if that's how you're using your amp.

After that there are isolation transformers you can get that will help clean up the voltage going to the amp if that matters to you.

Tripplite was mentioned on another thread.

Lucky that PI grid is 60hz even if it's 230-240 volts.

How did your Stereo Steel blow the one side?
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Douglas Schuch · From: Valencia, Philippines

Jerry, thanks for the very thorough answer - I will have to read that one several times to digest all the info. If I am understanding you, you are saying that the Stereo Steel is not outputting stereo UNLESS you use a stereo FX unit with different FX settings for each channel. Otherwise, it's two identical mono outputs. Correct?

As for what I am trying to achieve: I'm not trying to get a "stereo effect" - just trying to cover a large, open-air resto-bar were I play with good sound, and avoid two identical signals having any "cancelation effect" in the middle if this is indeed a real thing (which independent reading seems to imply is). As for gear, I have to good speakers (Telonics 12 and Sica Neo 15), and the Stereo Steel - currently running one channel only since I blew the other, but right now we are just rehearsing (in the same venue, but off hours). Hoping to have the Stereo Steel repaired within 2 months. Using the PA system is not really an option - it's a very minimal system that has to run at least 3 mics, plus possibly the gooseneck mic on my dobro, and the mic or pickup for the acoustic guitar player.

Godfrey - I had a bad speaker cable that shorted and blew the power amp module on the Stereo Steel - at least, that seems like what happened. GD Walker (Mr. Stereo Steel) talked me through some testing to find the problems, and I ordered parts that should arrive in a balikbayan box around Christmas. I will ask the one guy in the local music shop who is knowledgeable and good for amp repairs to do the work, but with GD's instructions.

I'm using a step-down transformer - no problems so far. I should take my meter and check voltage where I play - here at the house it's pretty low - typically 190-200V. One of the attractions of the newer speakers (like a Quilter 202 Tone Block) is the ability to run on any voltage between 100 and 230V - so the dirty power here in the PH is not such a big issue, and no need for a transformer (which is as heavy as the amp!). I'm not too worried about carting gear around - since I currently only play at the one location and they have a store room for gear, I can leave my amp and one speaker there.

Thanks!
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Jerry Overstreet · From: Louisville Ky

Bill C. Buntin · From: Cleburne TX

I did for a few years with stereo Evans setup. I liked the tone I got. And it was a powerhouse rig, lots of head room. And I agree that the stereo effect was realized only by me. All it did extra for me was make me relax and really enjoy playing. Band and audience could tell no difference between that rig and a single Nashville 400.

Overall, worth the extra on house gigs where you setup for 4 or 5 nights.

Not worth the extra, to me, on one nighters.

Bill

Jeff Highland · From: New South Wales, Australia

I'm not gigging, but I have a selfbuilt 50W per side stereo valve amp at home.
Gives me a nice full sound but unless I deliberately use an effect which pans aspects of the signal, I basically have a dual mono amp. Some effects like my marshall vibratrem give a nice ping pong effect.
But I'm only doing this for my own enjoyment, it would not work on stage for all the reasons listed by previous posters.

Douglas Schuch · From: Valencia, Philippines

So I got in touch with GD Walker, and indeed, the Stereo Steel is two separate channels, each carrying the same signal from the pre-amp. He says he set up the effects processors he sold with the amps with some stereo-effect pre-sets for those that wanted to try that. He also said having two different brands of speakers and different sizes two effectively creates two separate signals.

I've also tried to find any info on sound cancellation/interference from the overlap of two speakers running the same signal - something I probably read many years ago - but can't find any mention of it from two speakers spread apart - so maybe the angles of sound waves coming from the speaker prevents that from happening. I looked at a fair amount of info on PA systems, since they often run mono through multiple speakers, and could find no mention of cancellation or other interference effects - only possibly slightly-increased volume. There IS info of the effect from a single speaker placed close to a wall behind.

So I've basically concluded I'm fine running two speakers on a single amp set up for it if I can't get the Stereo Steel up and running again. I'd buy another Stereo Steel for sure - except that power here in the Philippines is so problematic! I am currently using a transformer as heavy as the amp itself! So the ability of a modern Class D amp like the Quilter Tone Block 202 to run on any power from 100-230V might cause me to give it a try!

Thanks all!
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Peter Harris · From: South Australia, Australia

FWIW, when I'm not dealing with stereo effects generated by a Guitar-synth unit (which get sent L & R to two individual Roland Cube 60 amps), I merely send a mono Guitar signal to one amp's normal input, and run another cable from the amp's rear-mounted 'Tuner Out' jack to the input of the second amp.

These amps are located L & R of the stage.

I built a custom footswitch panel (using DP momentary switches) which allows me to control channel and effects selection on both amps simultaneously.

Consistently gives me a good spread of stage sound, and band members can hear what I'm doing.

Slightly off-topic, but it might give someone else some ideas.

HTH
Peter
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