Monitor 30 distortion questions

markw300d

Hi gang....this is my first post. I recently purchased a pair of Monitor 30's on sale at Newegg. They were well reviewed and seemed like a good value. I've had nice audio equipment off and on since about 1980 when great gear was fairly inexpensive while I was stationed in west Germany. Since I've been laid off, I was forced to move some gear and down size a bit but I'll never be without music in some form. I thought these would match up well to nice little vintage Sony integrated 50wpc amp that I have (TA-F40).

The problem is if I get the volume a little more than past 1/4 of the way, the speakers will distort on certain songs and notes. One example is the "P" when Paul Simon sings "..poor boy.." in Diamonds on the Soles of Her Shoes". I hear it when some of the guitar notes are picked aggressively on a Chet Atkins/Mark Knopfler disc. These are just two examples. I've never pushed this amp beyond 1/2 volume even with my Dynaco A25's so I know there is no clipping going on but it is sort of a scratchy, popping sound. I swapped L R speakers and it still occurs. I can tame it by not moving past 1/4 vol. but where it starts to happen is nowhere close to their rated handling power. It's not my amp. It sounds great with my Dynaco's.

Has anyone else seen this with these? Do they just not handle much power well without distorting or is there an issue? When they sound good...they sound real good. This is intermittent but it is distracting and annoying. I don't listen to music loud and I take good care of my gear. I can still send them back to Newegg I think but I will be out the shipping costs and possibly a restocking fee.

any feedback is appreciated....
Mark

Sherardp

Sounds like you need more power. I seriously doubt the Sony is actually 50wpc. Try putting them on a different power source and see if you get the same thing.

Amherst

Agreed^^^^^

Had a pair of the 40's and 30's here. Pushed both sets with a full 125wpc external amplifier, they handled it very well. Clean right up to the clipping point.
I really believe these speakers represent one of the best values in audio at their price point. Try em on something else if possible.

Welcome to Club Polk!

cnh

Agreed, I've run these, briefly, on an Adcom 200w/channel at 8 ohms....no problem..they sound fine!

Do you have another amp or even AVR you can try with the Polks? I suppose it is possible you may have damaged the tweeters--clipping the Sony? Don't really know without having another amp in the mix.

cnh

markw300d

I seriously doubt the Sony is actually 50wpc

That's what the specs are....I haven't actually measured it. I've never heard of needing a 100wpc + amplifier to drive a set of bookshelf speakers. These are advertised as being efficient which should mean easy to drive. Quote from Polk..."They are highly efficient, so they can be driven easily by unpretentious receivers". Does this not contradict what i am hearing here? If power is the issue, why does it not occur at lower volumes and occur when I increase the power? I have used this amp with B&W 602 s3's, DM 303's and Dynaco A25's with no issues. I will try another amp if I can round one up but I don't buy a speaker like this needing that much power.

thanks for the feedback,
mark

markw300d

I ordered caps to recap the pulse power supply in the Sony yesterday just because it's 30 yrs old or so and if the caps fail in these, they can take out other components. I'll see what happens after the recap. This series of Sony amps were very nice units in their day.

Mon40CSMM10

I find that the Monitor 40's have a very bright and efficient tweeter--it's not harsh, but when the lower binding posts are disconnected in a bi-wired configuration (thereby disconnecting the woofers) it is very obvious the tweeter can reveal a lot of details in the recording even at lower volumes.

As I understand it, the Monitor 30's have one woofer instead of the dual woofers that Monitor 40's have. The tweeters should be very similar.

Is the distortion actually in the recordings being mentioned? To prove or disprove this, listen to the recording using a set of good quality headphones and turn it up to a loud enough volume without audibly clipping. Is the distortion also there?

Amherst

Mark, I wouldn't say these particular speakers need 100wpc to be driven. They are very revealing though and may be showing the limitations in your rig.

On the other hand, they really do like plenty of power if you want to drive them there. It will need to be clean sourced and properly set up because of the resolution.

Forgot to mention.... make sure both sets of binding posts are tightened down real good on the jumper between the lows/highs on the rear of the speaker.

markw300d

I appreciate the advise and realize speakers respond differently to different amps. One file was an MP3 file but I've heard it on a cd disc as well. I will try to find several files and check with headphones on the amp and the my pc. At first, I suspected the recordings but hadn't had a chance to check yet. I will start there and do this here in a few. I did make sure all posts were tight and jumpers were in place as soon as I first heard it. As for revealing, my recapped Dynacos are a very clean sounding speaker with clear highs and a great midrange that I've never had an issue with when used with this amp. If the source files prove good, I will try to borrow an amp and see what happens. While it may be true that the speakers are revealing things with my rig....I can't rule out yet that the opposite may be true.

thanks again,
mark

markw300d

re: the tweeter.... This is coming from the driver.

josephclemente

So all of the audio is coming from a PC? Could the PC's volume mixer settings be set too high? Have you tried a device other than a PC as an audio source?

comfortablycurt

I seriously doubt that the amount/quality of power is the issue here. This is a pair of Monitor 30's we're talking about...they don't need a lot of power to sound good.

cnh

markw300d wrote: »

re: the tweeter.... This is coming from the driver.

I think Curt may be right. You may just have a blown set of tweeters or some damage there. It is not that hard to fry a set of M-series tweeters--there are reports of a number of people clipping their amps and taking their tweeters out. If so and you're under warranty....no problem Polk will send you replacements.

Sounds like you have enough experience to be able to tell if this is a problem..maybe it's time to pull those tweeters out and have a look? Check the crossovers as well.

cnh

markw300d

Tweeters are fine...I'm sorry if that was confusing but this was coming from the 5 1/4" driver.

No, this wasn't PC music although some of it was ripped on my PC. This is a 70's Sony TA-F40 50wpc integrated amp that has a very clean and detailed sound. I'm sorry for being slow reporting back but wanted to finish replacing some power supply and coupling capacitors in the amp.

I don't know if it was a combination of the speakers breaking in and cleaning up the signal with the recap or what...but I am happy to report that I only have one track that I am still hearing an issue on and that is at a higher volume than I would ordinarily listen to. One thing I did notice is that it would always happen where there was a very sudden change in the music like the way some notes are aggressively finger picked on an acoustic guitar. I had that on a celtic guitar cd and the Chet Atkins/Mark Knopfler disc. It was almost like the driver was distorting trying to follow that sudden change in sound. I tried my neighbor's AV receiver (older Pioneer) but it had some static in the volume control and didn't have the sound quality of my Sony so I didn't think it was a good test. I am not sure why I never heard it in my Dynaco's other than maybe the larger 10" drivers were more forgiving.

I'm glad that I didn't send these back and appreciate the feedback that I got. I would have lost nearly a third of what I paid in shipping and restock fees so it was well worth giving them an honest trial. I hate selling my Dynaco's but sometimes we have to do those things. The Monitor's 30's are a surprising little speaker and a great value I think. I like them better sound wise than the BIC bookshelves I had and the silver front looks great with my silver faced Sony equipment.

thanks again for the help....
mark