Getting overtone in a pair of bookshelf speaker.

I just bought a pair of Music Hall Marimba bookshelf speakers, and currently experimenting with placement. I changed the previous height of the tweeter by placing two books under each cabinet. During the first listening session, they sounded OK, but now today after the changes made, they sounded crinkly in the high end with somewhat of hollow overtone in the midrange.

I do not expect them to pressurize a 12X14 room with full sound, but I am a bit disappointed at the tonal balance. I have them about 4 ft from the side walls and 15 inches from back wall which is glass, but has slat shades that can be closed. They are approx 5 ft apart and occupy the far end of the long axis. Need suggestions on how to find ideal tonal balance. Thanks
"they sounded crinkly in the high end with somewhat of hollow overtone in the midrange."

I have no clue what this is suppose to mean.

Can you return them. There are so many good speakers you could have bought used like Von Schweikert VR-1s or Green Mountain Audio Europas.
You need to give them at least 40-50 hours to break-in, (maybe even more). I wouldn't get to critical until you have some time on them.

You asked a few weeks ago about recommendations for a small speaker and got a lot of good advice. The Marimba's would have been one of my last choices. Sorry, just my opinion, but you really could have done better. Hopefully these will work out for you.
Jim, the guys are dead right on this one.
Try moving them out 3-4 feet from rear wall and a foot or two from sides with each tweeter firing 2-3 feet to the side of your main listening position, not directly at you. Make sure tweeters are near ear level and speakers are firmly supported on stands. Avoid early reflections from walls and whatever the speakers might be sitting on. Not a problem generally with proper speaker stands.
give'em 4...500 hours of break-in or whatever. if they don't sound good out of the box it will not improve. break-in only helps to ones sounding good to sound softer with less of edginess that is usually present in the speaker. tonal balance issue implies to poor crossover design.
for cheap speakers in general is the best to go active. M-Audio audiophile active bookshelves have the tonal balance adjustable the way you like.
Wow, got a lot of flak on this one. It is not the end of the world; I will just sell them if I dislike them or made a mistake.

To Mapman: will follow your prescription and see what happens. I am not sure about the usefulness of aiming the tweeters 2-3 ft to the side, but I will that a shot.

To Rrog, I owned a pair of GM Europas about 8 years ago. Very nice speaker, but was a bit bass shy; They also are expensive used and heavy to ship.( there is a pair on AG now or was) As far as Von Schweikert VR-1, there was a pair on AG about a month ago, but could not come to agreement on price with buyer.I am still not convinced that this is the best bookshelf value out there. BTW, I bought the Marimbas from an internet dealer who may have not have an official return policy, and he does not have another speaker in his inventory that interested me in my price range

MoFI, the Marimbas have about 7 hours on them, so I am far from Nirvana. 400-500 hours seems alot as recommended by Marak

I do appreciate everybody's commments and advice, but there are many speakers out there to consider as an alternative to my main speakers. Totem's Dreamcatcher; Rainmaker, and even the short floorstanders like the Arro and Stff models are viable choices.

The Epos 5i and 12i though discontinued seemed to be favored by Bob Reina of Stereophile. I believe I auditioned the original M-12 about 7 years ago, and was impressed by "how right they sounded" I don't have the opportunity of auditioning that many speakers in Honolulu because the 2 only high end dealers display 2K and above speakers because every turn must count to stay in business.

As MOFI noted there are many choices out there; manybe I should have spent a bit more money and bought the freakin VR-1. Nevertheless, I am having fun.
"To Mapman: will follow your prescription and see what happens. I am not sure about the usefulness of aiming the tweeters 2-3 ft to the side, but I will that a shot. "

The main thing is to at least try having them not fire directly at you, but to either side of "the sweet spot" where you listen, possibly with speakers far apart and out from rear wall and closer to side walls. That will affect the high end and upper mids maybe for the better. Then play with teh placement away from the walls so no early reflections and to get the soundstage and imaging tuned in. Asymmetrical placement may even be OK. Listen for "holography" in the sound with this kind of placement, sound seemingly disassociated with the actual location of the speakers. You will be relying on reflected sound heavily rather than direct sound in a more typical nearfield listening type setup. Its all good (when it works)!

This are some things I have found useful in similar situations with small monitors in smaller rooms. Its easy and cheap to tweak speaker placement and I would always attempt to get a handle on that before jumping ship on any particular pair of speakers. There are many other tweaks that might be worth a try also once the speaker placement issue is addressed.
"MoFI, the Marimbas have about 7 hours on them, so I am far from Nirvana"

You need to put a lot more time on your speakers before you even listen to them. With only 7 hours on them, you should be able to hear a noticable difference in how they sound every few hours. At 30 to 40 hours they should start to level off, but you need to put at least 100 hours on them before you judge anything. Use white of pink noise at moderate volumes if you can.

What kind of amp do you have?
Have you tried a little bit of single-malt Scotch?
TO ZB542, The amps are a pair Red Dragon digital monoblocks, and a Bel Canto PRe3 line stage. Speaker cable: Audio Art SC-5 (not special edition, that is the SE version)
1800 hours of break in will improve them..then you can go out and buy some good speakers!
Jim, You mentioned the speakers sounded ok until you raised them up. Maybe you should lower the speakers to their original height and just listen for a while as your new speakers break in.
TO Rrog, Actually, I followed Mapman's plan, and it improved the sound alot. The stands I have are semi-crap and are 24 inches high. I elevated the speaker to bring close to ear level. But, I will try your suggestion. There is lots of Koa wood in the islands which is very dense. If I could find a local woodworker to build me a pair of stands, that would be great

To Quad-man, these are $350 speakers. Despite Roy Hall's brittle personality, the guy is no asshole. The Marimbas are above average speakers and may get better. Though I have a feeling that Mike Creek had something to do with designing them. These are not my main speakers, and am just pushing the envelope of the budget class speaker. Why?? It offers an alternative diversion to leering at 20 year old college women on the beach

If you have any questions for so-called better bookshelf speakers, bring it on; I am open to suggestions
Take a look at Stereophile's round up of bookshelf speakers reviews, they seem endless.
Glad to hear. Good luck!