First time entry; have some questions

[Amateur Jerry]

Hello Friends,

I have been a lurker on this website for awhile and it’s my first entry. I have found the threads and info pages fascinating. Excuse my long entry, but I am looking for some help and have some questions.

I am more of an audio than video enthusiast, and my question(s) are targeting towards a little different application than the usual audio. My interest(s) and application(s) are digital piano and digital church (pipe) organ. I have both at my house. I would really be interested in some feedback. My questions are going to be related towards the piano.

When I am referring to a digital piano, I am not referring to a Walmart toy, I have a Kawai CA-63 that is considered an upper grade instrument in that market. It ran ~ $2700. Its touch, action, and resonances are really close to an actual piano and beside the realistic look, the former attributes are what drove me to the instrument. But one of the great downfalls in 99% of the digital piano’s is their inability to produce pure lifelike audio. The timber is realistic to an acoustic piano, but the audio output never seems to stack up. Unless one can fork over about $15K for Yamaha Avant Grand, digital pianos always seem fall short.

According to the Kawai manual:

Audio: 50w x 2
Speakers: 5” (13cm) x 2 / 2 (5cm) x 2

The manual states the piano has two full range and two tweeters.

One issue that has been driving me nuts is the middle registers; key C3 (130hz) – B4 (493 hz). When I would play above or below those keys the sound is quite satisfying. But in those middle registers it’s twangy. Instead of the sound of the felt hammer hitting the string, it’s like a spoon hitting a pan. I worked all over the EQ settings within the piano and couldn’t come up with a good combination. Although, when I plugged in my Sennheisers, the piano was beautiful through the headphones. I hooked up the earphone jack and played through my desktop PC (2.1;, not bad. When I used the piano’s internal recorder, saved to a USB, and played the USB through a media player I was quite impressed, some nuances but on a scale of 1-10, I gave an 8. My problem though, I still had that twangy / bang-bang sound when I played through the piano’s internal audio. I don’t know why that is happening, maybe some of you may have an idea.

I tried going the virtual route and I got just as frustrated. A lot of the VST packages are memory hogs, not enough RAM, too much CPU load, lag time issues, not compatible with this or that sound card etc. Forget It! I stumbled across a couple Home Theater and Audio forums and started reading with the thought of if “I want good sound I should listen to the guys who know how to make good sound and use products that are designed to make good sound.” I began to wonder since the sound through headphones is good what if I had a set of quality stereo speakers and run as a 2 channel with externals. The problem is I didn’t have an amp to use.

Recently I had won a raffle at my work and one of the prizes that I could pick was a 2.1 sound bar. So I took that one (Sharp SL-70) and hooked up to the piano output to see if I solved my problem. It was AWFUL!!!! It sounded like two soup cans and bailing wire. When I ran the volume up on the piano the sound was worse than the internal piano and all the sub did was go thud-thud-thud. So my frustrations set me back more.

To see if the problem was a bad sound bar amp or were the speakers really that bad. I then got a hold of a pair of Bose 100’s (yes they’re old) to see if the sound would improve. I hooked the speakers to the 2.1 sub and to my surprise it was a vast improvement. Although the sub didn’t really have much affect the sound was going through to the speakers was quite nice. Not only was the sound better, but the twang that I was hearing before was gone. At about a 4 on the volume slider, the piano sounded much more lifelike. I had to put the 100’s back. Thus I started reading your guys audio advice and began looking for speakers. I bought a pair of Definitive Technology SM-45’s. I hooked them up to the sub, and it was love at first note. Not only is the timbre clear and lifelike, with the SM-45’s you even feel the note as the felt hammer would hit the string. There was weight in the keys, the base was throaty, the middle clear, and upper register were harp like. This digital piano has a lot of adjustments for string and damper resonance and the SM-45’s do an excellent job picking that up. The sub has really no effect on the sound. I get more bass from the speakers, so I am using the sub as a driver for the speakers. According to the SM-45 specs, only five lower keys are not covered in their frequency response; A0 (27hz) – C#1 (34hz), but I can’t tell any drop off what so ever.

Now I have some questions for you experts. First, is it plausible for me to continuing running the sound system this way? My practice room is really about the size of a bedroom. I measured, it’s approximately 900 cu ft. The reason I ask, is I bought (Radio Shack) Sound Meter and based on what I have I set up (the volume where the meter is 39 inches from the speakers) when playing it would register ~86-92db. OUCH! It seemed a little loud. What my surprise was how little I had to move the volume slider up to get that kind volume. The volume slider barely needs to get to a 2 and I am getting that kind of power. I tried the pink noise test on the individual front channels of my basement surround system and I was up at -25db (from a bottom -70db) on the volume control to get that kind of reading. Before, when I tried to get that kind of volume on the piano audio system I had to run the slider to 6. Is it the SM-45’s are that much more efficient than what the piano speakers, 2.1 soundbar, or Bose 100 speakers are? (BTW: Those Model 100’s weren’t bad, but they were somewhat directional. If I was stuck with them I would’ve used them). I just want to make sure I am not overlooking something and possibly creating a bigger problem in the future. (ie Overdrive - burnout the 2.1 sub/amp or blow the speakers) I really don’t have the room or space for a surround sound amp and big sub. My hope is if I keep the volume slider down where it’s at I should be quite safe. This should be no different than the analog out from a tv. I’d like to get a second opinion.

Also am I measuring PSL correctly? I am assuming that 39 in @ 90db is 1 watt. If I am correct I am amazed I am getting that high of an output that is so clear for so little input from the piano. I would also like to find out why the piano’s internal audio has such a twangy sound at those middle registers.

Thanks in advance for any feedback.

By the way, the piano is about 8” from the wall. I recently set the volume slider a little lower to get about 82-88db when sitting at the bench. Much more comfortable! I also towed the speakers in a bit and because one of the big mistakes that I believe the digital piano manufacturers make is the speaker placement fires low to the floor and high at your ears. A real acoustic piano generates sound behind the music rack. By adjusting the toe I am getting about 86 – 93 db behind the music rack, while getting the mid 80’s at the bench. With the resonances and louder sound emitting from behind the rack than firing at the bench it is truly more realistic.

I don’t believe one can truly replace the sound of a “real” 9”-10”concert grand with a digital, but I have sat at several good sized uprights and grand pianos in personal homes, and the digital now sounds really close and in some comparisons I feel it sounds better. There have been two people who said it sounds better than their acoustic upright. I guess I will now look at digital pianos like buying a HDTV. Don’t buy the tv for the sound, leave that to the sound producing equipment, same with the digital piano.

Any feedback to the above would be greatly appreciated.

 

[Pyrrho]

With driving speakers with an amplifier, you need to concern yourself with impedance and power. Basically, if the amplifier can handle the impedance, and can drive the speakers as loudly as you need without distortion, it is powerful enough.

With your sound bar subwoofer amplifier, there is another matter. The amplifier for the sound bar portion is rated for driving just the frequencies from 200 Hz and above; the lower frequencies are handled by the subwoofer. Probably, that is not ideal for driving the speakers you are driving with it, but it should not hurt anything. I personally would get an amplifier (either a receiver or integrated amplifier or a power amplifier [preferably with a volume control]) to drive the Definitive Technology SM-45 speakers, but if you are happy with things as they are, you should be okay with what you are doing. And you might miss the subwoofer if you did as I would do, so maybe you should just go ahead and do as you are doing.


As for not liking the sound of your digital piano with its own built-in speakers, most likely, you simply don't like the sound of the speakers that are built into it. Thus, using other speakers that you prefer gives you sound that you prefer. And that also fits with you liking the sound through the headphones you have; you are using different speakers (the ones in the headphones) and liking the sound. If you want the best possible sound, you would probably want to go to all of your local audio stores and listen to all of the speakers you can, with a good recording of piano music, and pick the ones you like the best, and buy an amplifier that is suitable for driving those speakers. That could get very expensive, as the best speakers cost thousands of dollars. Of course, you could limit your auditioning of speakers to those that are within your price range, but if you are happy with the SM-45 speakers, there is no need to bother with looking for other speakers.

 

[Swerd]

Welcome to Audioholics. Your experience with the digital piano is interesting, and I think you understand the problem, and the solution. Substituting the Kawai speakers with headphones, the Bose 100s, or the Def Tech SM-45 speakers made a very noticeable difference. The internal speakers that Kawai supplied are probably cheap and inadequate, not unlike the speakers that come with TVs.

First, is it plausible for me to continuing running the sound system this way? My practice room is really about the size of a bedroom. I measured, it’s approximately 900 cu ft.

Yes, I don't see any problem with this.

Also am I measuring PSL correctly? I am assuming that 39 in @ 90db is 1 watt. If I am correct I am amazed I am getting that high of an output that is so clear for so little input from the piano.

That seems reasonable.

I didn't follow clearly what amp is driving your speakers. Was there an internal amp that Kawai supplied?

If you move to a much larger room, or move the speakers much farther away from where you sit, you may notice less volume. But for now, it seems like the internal amp that came with the piano gets the job done.

Those Def Tech SM-45 speakers seem like a good choice at a good price.

They got reviewed by Stereophile, and their measurements look pretty decent overall.

Definitive Technology StudioMonitor 45 loudspeaker Measurements | Stereophile.com

The review said there is a cabinet resonance at 320 Hz, but you didn't seem to notice that, so it may not be that offensive. What key is that on a piano?

 

[Amateur Jerry]

Q: I didn't follow clearly what amp is driving your speakers. Was there an internal amp that Kawai supplied?

A: Right now I have the piano headphone jack hooked up to the line in on the sub, and the speakers are hooked up to the sub. This is no different than the sound bar hook up instructions to a tv. If the piano had HDMI I would have used that. The piano puts out a lot more than a tv.

Q: The review said there is a cabinet resonance at 320 Hz, but you didn't seem to notice that, so it may not be that offensive. What key is that on a piano?

A: Luckily, there isn't a key at that frequency. It's between middle E (329.6 hz) and middle E flat (311.1hz). One aspect to consider, a real acoustic piano will have a resonance. Open the lid on any upright or grand, stick your head in it and say "HELLO", the strings will vibrate your voice back. On these upper grade digital pianos, that is programmed in and I have the capability of selecting the depth and strength of the resonance. If I hold middle C without a sound coming out and strike the next black key to the right (C sharp) with a short strike and release (known as staccato) and still hold the C, after C# releases I can hear C ringing. Those DefTechs are picking that up. Not only are the DEFTechs picking that up but they are picking up the sound wavering as it would be bouncing within the piano frame. I do give Kawai credit for programming that in, but their internal speakers were not performing like the DefTechs

In about a year my son will be graduating college, and after that financial anvil is off my back, I plan on upgrading my surround system in the rec room. It's just a Denon HTiB with an AVR-486. I am thinking that I'll put that and the HTiB sub with the piano and the DefTechs. I must say even though the sub from the soundbar isn't doing much for me, I am not noticing any loss at the lower notes. The DefTechs are picking up those low notes just fine.

I did some SPL measurements with the digital organ...There's some real funky stuff going on there. Would be a great thread someday.

Best Regards!