Piano World Home Page Forums Our Most Popular Forums Digital Pianos - Electronic Pianos - Synths & Keyboards Good PA System/Monitor for a keyboard?...

Happy Holidays to all...

I wanted to ask you for suggestions on a good monitor/PA system for keyboards. My keyboard speakers are OK for practice, but I'm sure a good external speaker would improve the sound. I also am joining a small group and will need something that projects the sound better.

The system doesn't need to be super powerful. The gig venues will be small parties at peoples' homes. But I want the sound quality to be as good as possible.

I've looked at the Roland Cube Monitor model CM-30, and the Behringer Ultratone K450FX. Both are under $200 and have 30 to 40 watts output power, which seems about right for me. Both are also fairly lighweight and are self-contained, having the amp and speaker in one box. I have not been able to listen to either of these, unfortunately.

Suggestions? Many thanks...

Roy

Rory,

What kind/model of keyboard/piano are you planning to amplify?

Is it stereo?

Snazzy

It's a rather basic Yamaha DGX-205. It does have a stereo output jack, but I wasn't really planning on getting two speakers. The Bose sound towers (for example, the L1) would support stereo in a single unit, but they are more than I want to spend, at least for now.

Roy

As far as I've experienced, most stereo digital piano sounds do not collapse well to mono. The sound seems to become more one-dimensional, and thinner. This is especially evident in Yamaha instruments, although other brands suffer from it as well.

You should try out a mono amp to see if you can live with the change in sound, before you buy, or at least, make sure there is a return policy.

You don't need an amp with effects, as the DGX has reverb and chorus, so the Roland CM-30 might be best. If you can afford two of them, all the better, as you would then be playing in stereo.

I tried the Bose L1 and it doesn't do stereo very well. My Yamaha P-85 sounded thin and I did not like the sound.


Most importantly, it will be better to have more power than you need, than to have barely enough to get by, as you will be working the amp/speaker very hard.

I'd suggest something in at least the 50 watt range.


Snazzy

We have the Groove Tubes SFX Spacestation Mark II, which implements stereo in an interesting way. One 100W amplifier is connected to an 8" driver w/ integrated horn tweeter pointing forward; L+R are sent to it. A second 100W amplifier is connected to a smaller fully exposed full-range driver at right angles to the main driver; L-R are sent to it. In this way, stereo emanates from what is essentially a point source. Really interesting to listen to the effect.

The main driver is in a box that is really too small for it, so the bass is somewhat weak and boomy. It doesn't sound too much worse than other middle of the road PA gear however. It easily gets loud enough to play small clubs and halls, even with a drummer present.

See the tread "I just bought a RD700GX, what Now." That guy baicially said his Roland Cube Monitor was ppoor and was looking for something better. I wrote more detail there and don't need to repeat it here.

I think you need to budget at least 1/2 the price of the piano for speakers. Everyone wants to spend like $200 but you don't get anything usable for that.

If this is for a gig, you want PA speakers and stands and a good amp of at least 100W per per channel, not that you will ever turn the amp up past "2" but you need the headroom. To reproduce the sound of a piano you are looking at speakers of at least 10" diameter but 12 is more reasonable, again not because you want a lot of volume, you want the large diameter for the tone that you just can't get with small monitors.

The other thing about the stage vs. playing at home is that at home typically a piano is backed up to a wall. The wall really does improve and amplify the sound from the monitors. It you are out in the open, far from a reflective surface you will need a LOT more power. The other thing is that people suck up sound some how. Yo need more power if the room is full than if empty. The speakers that will blow your ears out in a small empty living room will sound weak in a backyard filled with people.

Thanks to all who replied....good info.

ChrisA, I had to chuckle a bit over your advice to get a monitor worth "at least half the price of he piano." My keyboard only cost about $240 so the $175 Cube Monitor IS more than half! But most peoples' instruments cost alot more than mine, so I understand your point. And I'll have a better keyboard in the next year or so, I'm pretty sure.

Also, good advice about having more than enough power. Better to buy it now rather than need another amp later on.

I just learned of a person who has a Cube Monitor so I can try that out and go from there, making use of your suggestions.

Best...

Roy

I'm not knowledgable at all on this topic, but I've formed an opinion anyway.

I think that PA for a gig and good monitor sound for home practice are two very different functions, and you probably can't solve them both with the same system.

I have a good pair of studio monitors on my DP, positioned so my ears are at the vertex of an equilateral triangle, nearly anyway. That makes the piano sound good to me. They wouldn't be adequate for a gig.

I don't have a gig solution yet. I played one outdoor church job this summer. I used the inexpensive (touch sensitive but not weighted keys) keyboard they had on hand, run through the sound board provided by somebody with a DJ business. The results were disastrous. Either you couldn't hear or you got horrible distortion. Between the sound board gain, the keyboard main volume, and the touch sensitive changes, I couldn't control volume at all. If I do that job again this summer I'll bring my own equipment.

What separates studio monitors (and other hi-fi speakers) from PA speakers is efficiency and ruggedness of the drivers. Higher efficiency drivers tend to have a rougher (more peaks and valleys) frequency response, which is caused by cone resonance - at higher frequencies and power this is called "cone break-up" which is a non-linear form of distortion. Hi-fi speakers lower cone resonance effects by damping the cone, which adds mass, which lowers efficiency. Hi-fi drivers also often employ shorting rings on the voicecoil, which makes the piston movement of the cone more linear when it is being driven near its limits, but again at the expense of efficiency. It's a classic trade-off.

Of course, PA drivers are inherently more rugged than hi-fi drivers. They have a stronger spider, a stronger surround, a voicecoil that won't burn out as easily, and sometimes incorporate extra heat dissipation technologies. The stronger spider and surround tend to raise the free-air resonance of the driver, limiting bass response.

That said, speaker design has advanced substantially in the last few years (I wish the same could be said for DP design) largely due to engineering modeling on the PC such as finite-element analysis. Several drivers now exist that are robust and efficient and low distortion enough to work in both environments. Selenium makes a horn driver that is quite flat, and a woofer that is fairly flat and fairly efficient. Mid-bass drivers from Eminence are also fairly flat & efficient.

If you feel like a bit of DIY I'd recommend you build your own speakers as the mark-up on them is insane - manufacturers tend to cut corners on drivers and crossover networks, and stuff them in boxes that are too small / poorly constructed. Speaker building is a wonderful hobby!

I'm currently working on a project that pairs a 6.5" Eminence Alpha-6A for upper bass & midrange with a Selenium D220Ti-8 and $6 JBL horn. When paired with a subwoofer, it should be good enough for use as a fairly high quality monitor or small very high quality PA.

Roy, I can't recommend the Behringer, because I've had experience with their products, and they aren't durable, nor are they reliable.

They're cheap; that's about it.

I'd go with the Roland...maybe two of them eventually. I know a few performers doing nursing homes and such, using a CM-30, and eventually upgrading to using two of them.

Snazzy

Here is a guy after your own heart, Dewpster, and there may some tips to help you along.

http://www.homerecordingconnection.com/news.php?action=view_story&id=32

It is a lot of fun. My friend Zeke and I built a really nice guitar amplifier, reminiscent of a Fender Twin, but using two full range Celestion 12 inchers, to enable the amp to be used for acoustic/electric guitars. Built it for less than a third of the price of a Twin.

Snazzy

I have a Roland CM-30 that I bought just for a small monitor, it does have a good sound, but limited power. I use it with an acoustic folk group (several guitars, banjo, doghouse bass), and it is enough; but it won't handle much more than that. Its primary use to me is that I can put it on a mic stand and get it a foot or so away to use for a monitor on my Kurzweil PC3 when gigging in a place that has good FOH PA equipment (use their system for the audience, monitor just for me).

I also have a pair of JBL EON 10G2 and a pair of JBL EON 15G2 - scalable amplification for anywhere that I gig. Places that are too large for the four JBLs to do the job generally have house sound systems and I connect to them.

The key is still - buy quality, buy once, spend less money. Buy thinking of scalability if you do gigs in a lot of places. If you buy junk - you will wind up losing.

Stereo vs mono - unless your keyboard has sounds designed to use in mono, they probably won't sound as good in mono. House systems are usually mono. My PC2 actually does have a couple of mono piano patches.

Wow...some good tech info here! Dewster's explanation of PA speakers' efficiency vs. that of a studio monitor was excellent!

Snazzy...yes, the nursing home circuit is about the level where I can play comfortably. One friend told me that my slow organ improvisations would sound OK in a FUNERAL home (seriously), so perhaps a nursing home would be good practice! (Please pardon my attempt at humor here...nursing homes are sad places where a little music would be good.)

I've read more about Behringers since my original post...sounds like good advice to steer clear of them.

I'm testing out my keyboard on a friend's Cube Monitor soon...will report my impressions of it.

Roy

I'll be interested to hear how you get on, I'm considering buying one CM-30 and then possibly adding a second later and I haven't found any shop where I could listen to them so I'll have to trust to luck and order online.

I hooked up my Yamaha DGX 205 to the Cube Monitor yesterday and it sounded AWFUL! It sounded like a REALLY cheap toy keyboard on several of the notes. It was NOT any kind of improvement over the onboard speakers. Now granted, my keyboard is not high-end, but the piano voice sounds pretty decent with the onboard speakers...not toy-like!

But before I condemn the Cube Monitor, perhaps there is more that I can do...

--My keyboard only has a stereo headphone output...no "line" output. Perhaps there is an impedance mismatch between the keyboard output and the amplifier input that would corrupt the sound? The Cube's and keyboard's manuals don't mention impedance values so I don't know if that's the problem or how to try to correct it.

--I think I need to experiment with varying the amplifier's channel gain, main amplifier gain, and keyboard output volume. Maybe there's a combination that would improve the sound?

--Maybe use one amplifier channel each for stereo-left and for stereo-right, rather than putting both into one channel?

Other ideas before I give up on the Cube? Or might the Cube just be incompatible with my keyboard?


--Roy

I'd definately try splitting the signal across the two channels of the cm-30, that's how it's intended to be used so hopefully the sound should improve significantly. Unless you're using a stero to mono adapter you may only be hearing one channel which would sound awful!

The Roland Cube Monitor 30 is wonderful. I have had many different amplifiers and monitors over the years, and the sound from my Cube is tremendous. Plus it has numerous input jacks and a output jack for connecting two.

According to the specs, the DGX-205 uses a "Stereo-sampled Piano".

It has been my experience with amplifying a stereo piano voice, that I must use a stereo system in order to hear the sound properly.

This is especially true of Yamaha stereo samples...they just do not collapse well to mono.

That's why your piano sounds the way it does.

That is also why I suggested going to two CM-30.

Is there a way to try the DGX-205 through two CM-30's?

Snazzy

ps...By the way, Roy, yes, your keyboard is not high-end, but it does have a remarkably good sound for the price. I've played the DGX-205 and it is a great value, in my opinion.

a pair of yamaha HS-5m is good enough. get the hs-10w if u need more bass.