Questions About My New 250TI SE

[superbee973]

Hello everyone, My name is Nick and I recently purchased some 250TI SE Speakers through AUDIGON. I want to thank everyone who assisted me with information about finding a pair of my "dream" speakers. Anyway, I have a few questions about this speaker but first I will describe my system as some have asked. I will also post pictures of the speakers from work tomorrow. I purchased them for $3400 and they look as new, although they will need a refoam now that I have played them loud. My system is at the bottom. I listen to mostly classic rock, jazz and classical. My original speakers were NHT 2.9 and Infinity RS-1Bs which I still have.

My initial question is: My JBL speakers seam to be really really harsh in the vocal area. I have tried different XLR Cables and MIT speaker cables and ven swithed in a Parasound 2200 MKII and a set of Aragon Palladians but the best I could get was with the set-up below. The timbre of the voice just is not right. My room is dedicated and is in a daylight basement that's 12.5'x28'. The speakers are on one end of the room, about 7 feet apart and several feet from the wall. The room is carpeted and has some furniture and built in shelves.......The seating position is about 12 feet out from the speakers. I have tried moving them around. Thanks

Audio Alchemy DDS Pro CD Transport
Audio Alchemy DTI32PRO DeJitter Device
Camelot Uther MKII Dac (All I2S Silver Cabled)
Llano Designs Amplifier (Deanna 200 WPC Class A)
MIT Proline XLR IC Cables
AQ Midnight Speaker Cables
JBL 250TI SP
(2) NHT SW3P Subwoofers/Amps/Xovers (250 WPC)
Chang Lightspeed 9600 ISO

[Nightbrace]

Thats unfortunate to hear :(, they are my DREAM speakers too! The fact that you played them LOUD has nothing to do with the surrounds going bad, they deteriorate with time, not by being overdriven. And I am assuming you just noticed it after playing them. Given their collectibility and exceptional sound, I would get the entire cone replaced and have them done right by a certified JBL tech.

As to why they sound harsh, well they are VERY detailed speakers, I doubt your room is the problem, I think it will just take time to get fully adjusted to them. I have had Infinities myself, Column II's, which were really tame, and many consider them to be the best Infinity EVER. I think its just that you have gone from relatively tame speakers compared to these 250Ti's, they are as accurate and detailed as they come, or at least that I have ever heard. And for me it doesn't get any better. I just pray that there's nothing wrong with them.

First things first, inspect the other 8" drivers, and use a good diagnosis CD at low levels to listen to the individual drivers to make sure they are all functioning. Then if all checks out, get the woofers repaired. And if I were you, I would be a little upset at the original seller if he didn't let you know about this before-hand. The good news is that I don't think you damaged anything. I hope all works out and you can get accustomed to these speakers, if not, I'd always be willing to take them off your hands :)/

[Nightbrace]

The timbre of the voice just is not right.

BTW, I have never heard anyone complain about this, JBL's make vocals come to life and bring the singer into the room, as JBL arguably builds the best midrange drivers ever made. AND YES the timbre should be different compared to the Infinities which will be warmer and smoother. If you have a Diana Krall CD, listen to her voice on each speaker, she will tell you which speaker produces vocals better :)/ But again, make sure the speakers are functioning properly, and get the woofers fixed. If after some time you are not liking these speakers, JBL is still the way to go, they have made tamer speakers, I have a set right now, the L112, which might be a little closer to the Infinities, and a heck of a lot cheaper.

The equipment you have is all World Class gear and my guess is that the JBL's are bringing out things that you have never heard, afterall thats their job; to utilize every ounce of whats given to them. Just make sure you are playing quality recordings as they can sound a bit harsh with poor quality recordings, but thats whats they are supposed to do, bring the flaws of the poor recordings to the listeners attention and make great recordings sparkle. >BE PATIENT<

[oznob]

Nightbrace is right on the money! I had 250ti's and too many others to mention. They are by far the most dynamic, accurate speaker I have ever heard, bar none! The height and width of the soundstage is without peer, IMHO. Most certainly get those woofers re-coned by a pro. Pay close attention to the mid-range drivers, I have a friend who blew one of the 5" mids and had to have it re-coned. Although rare, you may have a bit of a crossover problem that may need checking. I would hit up Giskard or Zilch on that. There are plenty more guys on this forum with much more knowledge than I have but, speaking as a previous owner, they should be knocking your socks off if working properly! :applaud:

Best of luck!

Mark

[Nightbrace]

Pay close attention to the mid-range drivers, I have a friend who blew one of the 5" mids and had to have it re-coned. Although rare, you may have a bit of a crossover problem that may need checking.
Mark

I agree Mark, and it almost sounds like a midrange problem to me from his general description, I have never encountered a crossover problem yet with JBL's, but if its a crossover problem there is a considerable risk that it may have damaged the drivers as well. We all need to pray tonight for Nick ;).

To be on the safe side, I think it would be smart to actually bring the entire speaker system to an authorized JBL service center, because you could be damaging them even more by using them.

Nick, would it be possible for us to see the original ad for the speakers? Maybe there's some information there.

And again if the seller was AWARE of any of these problems he needs to be held liable. Even if its as simple as a surround thats deteriorated, he should have at least let you know about it, especially for $3400, but these days you never know.

[glen]

... I doubt your room is the problem, .../

I'm not so sure it isn't the room, if all your basement walls are brick or concrete block they will increase the mid/hi frequency energy similar to the way bass can get out of control in a normal room. I had this experience when I moved into my 1927 vintage all-stucco house (plaster on lath masonry walls) my 4311Bs sounded very harsh and fatiguing and I had to dial the mid and treble way down for them to be listenable.

If you have the hard, brick walls you should do the mirror trick where one person sits at the listening position while another moves a mirror along flat against the wall. When the person at the listening position can see the reflection of the speaker in the mirror then that's the spot that should get some acoustical damping to eliminate harsh sound reflections. For a quick test you can tack up rugs or blankets and see if it helps to reduce the irritating effects you've noticed.

Good Luck!

[Zilch]

If the foam surrounds are deteriorating, do NOT play them any more until they are repaired, as it can damage the voice coils. Only the spider is maintaining the alignment when they play. Not good.

Having the woofers refoamed is MUCH cheaper than reconing them. Voice coils have to be good to do that....

[JuniorJBL]

I would first try to listen at low levels with music that you are familiar with.


(Maybe Dire Straits "Your Latest trick") That is a well recorded song as well as album.

Diana Krall (as before) will help with vocals.... on and on.

Your by-pass caps could be toast (mine were) and when I re-did my crossovers it was better but then I decided to upgrade mine to 250Ti's they were L250's. So another crossover (This time to be CC'ed) to be made for my upgrade.

As others have said they are very well behaved speakers that can handle quite a bit of power. One other thing might not be a prob until high volume is they were rated at 6 ohms with the Ti version. I am not totaly sure about yours but Someone else my chime in. Your equipment should be able to handle this but I have never listened to that equipment before so I do not know.

One thing is for sure if you are willing to follow the instructions that others will give then you will be able to find a solution.

It also sounds as if you may need to tweek your seating/speaker position a bit. Do not be afraid to move in close to the speakers or move the speakers from what might be a dead place (room mode)

Another thing you can do (you need two people) is to move one speaker all the way to the back wall facing stright forward at about where you will be spacing the speaker.

Then have someone point the other speaker about 12-18" behind your listening position and try to keep the speaker pointed there while moving the speaker away from the wall listening for LF response to become the cleanest it can.
Then tilt the other speaker the same 12-18" behind and start moving it forward as well. At this point you should be playing some good female jazz vocal and listen for the best image you can get. (where the speakers seem to disappear)

I learned this from a Sumiko rep and it has worked as well as anything else I have tried.

Keep us posted;)

Edit: I was writing when Glen and Zilch were posting and this is some good advice :thmbsup:

[Nightbrace]

I'm not so sure it isn't the room,
Good Luck!

Considering that he's spent this much on equipment, I figured that he would have a decent listening room :). And he did mention that the other speakers sounded good.

And by the way thanks for the suggestions, I have a masonite, "stucco", room, and it sucks for JBL's. I just moved everything into my other room, NIGHT AND DAY. But I will try what you said. You think a tapestry on the back wall would help?

[duaneage]

My 4411s had too much moidrange output in the room I set them up in, flat response speakers in a smooth walled room sound pretty hard. Dialing down the midrange controls licked it.

[baldrick]

The foam should NOT be damaged by you playing loud. The bigest problem with LE14 in 250TIs is that the voice coil damages too easy, maybe especially when 250s are beeing used in surround setup. This is the reason why two friends of mine is running a HP filter of 50 hz when useing them in their surround setup, and useing a seperate woofers from 50 and down. Another issue I think of is that the SE version is really not that old and the foam should NOT be damaged by age.

So my question, you are of course sure it's the foam that's broken and not the voice coil?

[JuniorJBL]

The foam should NOT be damaged by you playing loud. The bigest problem with LE14 in 250TIs is that the voice coil damages too easy, maybe especially when 250s are beeing used in surround setup. This is the reason why two friends of mine is running a HP filter of 50 hz when useing them in their surround setup, and useing a seperate woofers from 50 and down. Another issue I think of is that the SE version is really not that old and the foam should NOT be damaged by age.

So my question, you are of course sure it's the foam that's broken and not the voice coil?

This I have only seen with less than optimal amps. The only times I have ever heard an le14h-x pop is when you have average power amps. I was using Hafler XL 280's adcom 555MKII and if you reall got on it they would pop. But since I have moved to better amps this is no longer a problem. These things can and will "Rip your head off". With that said the LE14H-1 is not a boomy driver but has a real nice LF. and if they are in a smaller room they will have quite a bit of LF.

[4313B]

The only things wrong with the LE14H-1 stem from "user error".

It's kind of funny to read end user comments about various transducers once those transducers get into the wild.

[JuniorJBL]

The only things wrong with the LE14H-1 stem from "user error".

It's kind of funny to read end user comments about various transducers once those transducers get into the wild.

:yes:

[jblnut]

Just to add a little bit about getting 250ti's dialed-in...


As others have noted, this is an extremely revealing - and flat - loudspeaker. Although your list of components is very impessive, it does not necessarily guarantee success with these speakers. Building a good sounding system is often a trial and error process and many times a component that you used to think sounded great may no longer be "right" for the new configuration. I changed many components after the 250ti's went into my system until I found the right mix. I still find the upper midrange a bit too "much" for high volume classic-rock listening and that's what the EQ is for in my system. My only (lingering and mostly minor) criticism of the 250 is that I still feel the tonal balance changes somewhat as the volume goes way up. When I get it sounding perfect for normal levels, cranking the volume up makes it sound too bright. Taming the mid/high end for cranking sessions leaves it dull sounding once the volume comes back down. This is also an issue as I switch back and forth between vinyl and CD's.
I don't know if your 250Ti's have the fully adjustable xover bars on the back but this is another easy way to adjust them to suit your taste.

As I said it's a minor issue and simple to fix with a good EQ. I still wouldn't trade them for anything and that is the bottom line :) .

jblnut

[clmrt]

"Variable Loudness Control" is your friend.


.....DAMN! Another page 2 starter.:biting:

[baldrick]

This I have only seen with less than optimal amps. The only times I have ever heard an le14h-x pop is when you have average power amps. I was using Hafler XL 280's adcom 555MKII and if you reall got on it they would pop. But since I have moved to better amps this is no longer a problem. These things can and will "Rip your head off". With that said the LE14H-1 is not a boomy driver but has a real nice LF. and if they are in a smaller room they will have quite a bit of LF.

I don't know if you know Electrocompaniet very well "over there", but it's really state of the art amps, in fact Michael Jackson (!) on one of his albums made a "thank you note" to the creater of Electrocompaniet. But anyway to get to the point, two of my friends are running big EC amps on their 250TIs.

One of them are running two of the biggest EC monoamps, the EC Nemo, which is conservative rated to 1x600@8 ohm, 1x1200@4 ohm and the other one "only" a EC250R, rated at 2x250watt. (In Norway a set of Nemo costed aprox $10.000, EC250R aprox $4000) so it's NOT average power amps I'm talking about :) Both of them have had several "break downs" with their LE14 and belive me, those are not the only one I know have had this problem with the 250s.

If you wanna take a look at their stereos, take a look here (btw: both of them are useing Velodyne 18s as woofers):

http://avforum.no/minhjemmekino/show.php/Ulven
http://avforum.no/minhjemmekino/show.php/Mr.%20Digital%20Drive

A third Norwegian guy (who I really don't know that well) with similar 250 setup:

http://avforum.no/minhjemmekino/show.php/hitme357

[edgewound]

If you're looking to make massive, ear-bleeding SPL with the 250ti....look elsewhere. The 250ti is meant to be an accurate playback speaker to be used at non-concert levels. It simply won't do what a big compression driver based system will do....because it can't. Cones and domes for midrange and high's will never be able to do what compression drivers can do SPL-wise. They don't have the ability to provide transient response that compression drivers do. 250ti's do what they are meant to do...and do it beautifully....while looking beautiful.


Don't subject those beauties to abuse. Rather get something that has the ability to abuse you to your heart's content. Power compression comes first, burnt voice coils comes next...repeat these steps over and over....and sooner or later it won't matter.

Ask Pete Townshend;)

[baldrick]

I totally agree with you.. but what I was trying to say is that in fact several owners of 250TIs have had problems with burned voicecoils on their woofers (esepcially when used in surround setups), and that's why I asked the thread started if this was he also meant!

[JuniorJBL]

He could get 4 2242's in 10cu ft boxes and have all the ear-bleed you could want.... Highs would be a little low :p

[oznob]

I ran my 250ti's with an NAD 218 200 watt amp and they sounded wonderful! Take Edgewound's advice and give them some quality, not quantity, juice and I'm sure you will be more than impressed. A 10 watt set amp may not cut it but you don't something that will back the nails out of your house! Not to mention, your hearing will thank you. Take it from someone who survived 70's cover bands with Marshall stacks and SVT's, in a garage!:rockon1:
If you're looking to make massive, ear-bleeding SPL with the 250ti....look elsewhere. The 250ti is meant to be an accurate playback speaker to be used at non-concert levels. It simply won't do what a big compression driver based system will do....because it can't. Cones and domes for midrange and high's will never be able to do what compression drivers can do SPL-wise. They don't have the ability to provide transient response that compression drivers do. 250ti's do what they are meant to do...and do it beautifully....while looking beautiful.


Don't subject those beauties to abuse. Rather get something that has the ability to abuse you to your heart's content. Power compression comes first, burnt voice coils comes next...repeat these steps over and over....and sooner or later it won't matter.

Ask Pete Townshend;)

[DavidF]

I totally agree with you.. but what I was trying to say is that in fact several owners of 250TIs have had problems with burned voicecoils on their woofers (esepcially when used in surround setups), and that's why I asked the thread started if this was he also meant!

Wow, failures in JBL woofers in domestic setting, even in use as surrounds, with sub woofers, high quality amplification, what the hell is the signal source? Assuming there is simply no other explanation for driver failure I could not be in the same room at the sound levels I would expect to be needed to cause a failure.

DavidF

[superbee973]

Thanks everyone for your comments. I think I know what the problem is. I did not mention that i recently added on to my listening room by removing a wall that extended the length of the room from 19 feet to 28 feet. That new section of 9x12.5 is where my equipment and speakers are. Even though the main room is actually pretty dead (masonite panaling, accoustic drop ceiling & thick carpet), the new section which is completely sheet rock, has a slap echo that is really loud. Looks like I'll need to do something in this part of the room to restore balance. Also, When I purchases the speakers (They look new), I noticed the surrounds felt a little gummy and soft in several places. The one place that I rubbed on several times is where a piece about an inch long fell off while I was playing themn really load. I only notices because I heard what I expect was the woofer motor rattling so I discontinued using the woofers. Where can I safely get them refoamed and checked? I'm in NJ and would hate to "ship" since I know how UPS is. Anyway I am still listening to the top crossed over to my SW3P's. I can hear nuch potential. If you noticed by system I did mention a pre-amplifier. When I fiirst hooked up the speakers I was using my Parasound P/LD200 Balanced Pre and it sounded bad. I removed the preamplifier anad it sounded a lot better. This was not the case with my past speakers. I know the Parasound is not great, but ir did beat out a Bat vk5 in my system previously. I'm looking for a really good pre now. Thanks All.

[clmrt]

$300 in maintenance right now and you'll be a happy, happy man.


...and I don't think I like my cat staring at me like that.

[Steve Gonzales]

Your L250ti SE's should abosolutely rock your WORLD!. The LE14H-1 is one of the best LF transducers that JBL EVER produced!. No doubt the foams are to blame for the lackluster performance. That would explain some of the bump in the midbass. Get your woofers fixed and try an amp with 250-350 wpc and ALOT of dynamic headroom (Yamaha MX1000u = +3db.) and NO SUBWOOFERS. I've been astounded at the lack of (clean) dynamic headroom provided by some very well regarded and expensive amplifiers. I had an SAE P250 that had a toroidal power transformer that weighed about 30 lbs by itself and huge power supply caps to boot. The thing was in perfect working order and plugged into a 40 amp dedicated outlet. It was rated at 250 wpc and at 251 wpc, it fell flat on its butt!!. Now, you may not think of an older Yamaha power amp as very desirable, but these amps are a PERFECT match for your L250's. Take some time once you get the woofers fixed and try different crossover settings ( I think you have the buss bar type?). These speakers will thrill you if set up properly. I use LE14H's in my modded L222's and MAN ALIVE, they deliver huge pressure waves of clean, articulate LF. I believe that these speakers are so well designed that you'll definately have a CRAP IN-CRAP OUT thing goin' on there. Not all high dollar equipment is compatible with every speaker. Shop around and see if you can network with other people interested in audio, see if you can 'test drive' amps, preamps, CD players. BTW, the LE14H-1 is also used in the Citation 7.4 subwoofer, again, it is NO SLOUCH. Good luck with your system, Steve G.


More thoughts: My brother has owned a pair of L250's since 1984 and I've spent countless hour listening to these wonderful speakers. Although I am a fan of compression drivers (my system has no less than 10), this is one of the VERY FEW speakers that I never get tired of listening to.

[Steve Schell]

Nick, it sounds like you are getting a handle on what is wrong. Like Glen, I immediately thought of room problems when you described the irritating mids. Your JBLs likely have a more prominent midrange response that your previous speakers, which probably have the scooped out midrange response typical of most modern speakers.

Often a room will recycle and build up midrange energy more than highs and lows. Once you get your woofers fixed, you might want to do a little experimenting. Grab every mattress in the house and lean them against your side walls. Throw whatever other absorbent material you can find in there temporarily, and see if that doesn't tame your room and speakers. As I have become acutely aware of recently, rooms are nasty things sound-wise, and eliminating room effects to the extent possible really helps the speakers to sound their best. Listening to speakers outdoors away from reflective surfaces is an eye opener; they often sound much better than they do indoors.

[DavidF]

"...My initial question is: My JBL speakers seam to be really really harsh in the vocal area...The timbre of the voice just is not right..."


You may find some subtle changes in moving your listening position both in terms of distance from the speaker and ear-level axis. You may hear some difference in the upper mids-lower highs moving up or down in the vertical axis.

David F

[pangea]

I don't know if you know Electrocompaniet very well "over there", but it's really state of the art amps, in fact Michael Jackson (!) on one of his albums made a "thank you note" to the creater of Electrocompaniet. But anyway to get to the point, two of my friends are running big EC amps on their 250TIs.

One of them are running two of the biggest EC monoamps, the EC Nemo, which is conservative rated to 1x600@8 ohm, 1x1200@4 ohm and the other one "only" a EC250R, rated at 2x250watt. (In Norway a set of Nemo costed aprox $10.000, EC250R aprox $4000) so it's NOT average power amps I'm talking about :) Both of them have had several "break downs" with their LE14 and belive me, those are not the only one I know have had this problem with the 250s.

If you wanna take a look at their stereos, take a look here (btw: both of them are useing Velodyne 18s as woofers):

http://avforum.no/minhjemmekino/show.php/Ulven
http://avforum.no/minhjemmekino/show.php/Mr.%20Digital%20Drive

A third Norwegian guy (who I really don't know that well) with similar 250 setup:

http://avforum.no/minhjemmekino/show.php/hitme357

From what I have read on your links, you have been playing V E R Y V E R Y LOUD.

You mention things coming down from their shelves in the kitchen, among other things.

Don't you think you may have over driven those speaker just a tad?

If you like to play that loud, then perhaps you should go for the PRO/PA stuff, or at least put some limitation on the output.
A Behringer Ultradrive as x-over if you go active, can ad some limitation, if you can't avoid getting too wild on the SPL's with those speakers.

A 2" driver, like the 2450, a 2226 and a 2242 as sub, if driven actively, will play just as clean, yet even louder, but the difference is, they are made to play at those sound pressure levels.

So please don't blame the 250Ti's, they're simply not made to be used that way.

BR
Roland

[Raffe]

About the "bad" midrange, I experienced problem with one of the 250Ti lim Ed, it sounded "harch" and wrong.. It was a shortcut between a filter coil that resulted in to much high freqvency from the 8" mid bas(fabrication fault). I play them biamped with Yamaha MX-1000, and tested to play the sub and mid bas alone, then the faulty filter was easy to hear.

The Yamaha MX-1000 sounds realy nice trough 250Ti..

250Ti is a WERY nice speaker!!

[baldrick]

From what I have read on your links, you have been playing V E R Y V E R Y LOUD.

You mention things coming down from their shelves in the kitchen, among other things.

Don't you think you may have over driven those speaker just a tad?


I think you are getting a bit confused... because this is NOT my system, I don't own any 250TI, but 4435 :)

[jblnut]

Check the archives - there are some good threads on pre's in there. From cheap to expensive you might check out:

Yamaha C80/85
Carver C1, C4000, C19 (tubes)
Adcom
Luxman (pre-82 Alpine takeover)
Threshold/Forte
Conrad Johnson (they make some killer tube pre's)

I'm considering the move to a tube pre myself. Since they are just a pre they don't have all of the same drawbacks of a full-on tube amp. Yet they can impart much of the same smoothness to the sound while still leaving you to use big transistor power which the larger JBL's crave.



jblnut



I know the Parasound is not great, but ir did beat out a Bat vk5 in my system previously. I'm looking for a really good pre now. Thanks All.

[Nightbrace]

Just wondering if things have improved :), here's hoping,

[superbee973]

and doing some room treatments with rigid fiberglass. Got a SF Line 3 SE Pre & Processor 3. Hope to get it all together in a few weeks. I've been away so I have not got here in a while..Well I'll keep all posted....later!

[lpd]

I'm by far not an expert on this topic, but I have owned a pair of JBL L-250's. I actually traded a pair of 4333's for them. I was surprised at how flat they sounded. My only complaint was that the midrange sounded as if it was "filtered" through a cloth...although at that point my ears had grown fond of the 2420 drivers on the 4333. I had to play with placement to get them right, but once i found it I was in audio heaven. I used a Threshold S150 for power. It seemed just right for me, although I don't listen at concert levels.

[Rusnzha]

If you have the hard, brick walls you should do the mirror trick where one person sits at the listening position while another moves a mirror along flat against the wall. When the person at the listening position can see the reflection of the speaker in the mirror then that's the spot that should get some acoustical damping to eliminate harsh sound reflections. For a quick test you can tack up rugs or blankets and see if it helps to reduce the irritating effects you've noticed.

Good Luck!
I'm interested in trying this suggestion, but I'm not sure if you are moving the mirror along and damping out the front or rear wall or which direction you are looking toward from the listening position to see the speaker in the mirror. I'm probably complicating things unnecessarily, but would appreciate clarification. Thanks!

[johnaec]

Where you see the speaker in the mirror is the point that direct reflections will be bouncing back at you. Think of the room like a big pool table, and the spot where the mirror reflects back is the same as the spot where the billiard ball hits the edge and bounces back to you. 'Same principle applies here.

John

[glen]

Quote:
Originally Posted by glen

If you have the hard, brick walls you should do the mirror trick where one person sits at the listening position while another moves a mirror along flat against the wall. When the person at the listening position can see the reflection of the speaker in the mirror then that's the spot that should get some acoustical damping to eliminate harsh sound reflections. For a quick test you can tack up rugs or blankets and see if it helps to reduce the irritating effects you've noticed.

Good Luck!



I'm interested in trying this suggestion, but I'm not sure if you are moving the mirror along and damping out the front or rear wall or which direction you are looking toward from the listening position to see the speaker in the mirror. I'm probably complicating things unnecessarily, but would appreciate clarification. Thanks!

Since your main problem is with the vocal range I wouldn't worry about the front wall since that would have the greatest effect on the sound radiated from the back of the enclosure which would be mainly bass. I believe the best place to start would be with the side walls, and the floor if it is hard and reflective. These are usually the source of the reflections that are the closest in time, and cause the most interference with, the sound you hear directly from the speakers. Then you can move on to the back wall. Sit at your normal listening position, but you can certainly turn your head to look at the mirror. Do try to keep your head at the normal listening position even when you are turned all the way round to look for reflections from the back wall. Since your problem is mainly with the vocal range you will mostly be looking for the reflection of the mid-range driver. When you see it in the mirror that is flat against the wall you have found the point along the wall (or floor) that you will want to acoustically dampen. Also remember that sound spreads and is not as focused as the mirror's reflection, so you will probably want to apply damping a couple of feet around the point where you see the reflection. I would try a quick, temporary solution damping the reflections, thumbtacking up blankets or propping them with broomsticks and see if you do get a marked improvement in the sound, and you are on the right track to a solution.
It would take a pretty reflective room to cause the kind of harshness in the vocal range you describe. But I ran into it in with my stucco living room with hardwood floors, two glass fron bookcases and a glass top coffee table and you just might have a similar situation.

[Rusnzha]

Glen And Johnaec

Thanks for the clarification. I am looking forward to seeing what kind of improvement this can make. I will be back to describe what happens.