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Poor Midrange on Polk RTi A7's

24K views 40 replies 16 participants last post by  Geoff4RFC 
#1 ·
Hello all, I'm new to the forum so I hope this post doesn't cause too much of a stir.


I recently bought a Polk RTi surround sound system, set up is as follows:


Receiver: Yamaha RX-A810

Amp: Adcom GFA 555 2x200W (for fronts)

Fronts: Polk RTi A7

Center: Polk CSi A6 (still in transit, has not been received yet)

Surrounds: Polk FXi A4


After getting everything set up I have to say that the A7's are fairly lacking in the midrange. The best way I can describe it is that there is sort of a "hole" in the vocals, which seems to be more noticeable when watching television/movies. I believe the area in which there is a problem is the upper midrange. Voices in that are high or extremely low come through well, but the majority of voices which lie in the middle range sound distant.


As I indicated above, I have ordered a CSi A6 center channel but it is not here yet. The receiver has the center channel set to "off" so all the signals that would normally be going to the center are going to the fronts. Someone pointed out to be that the issue is probably the high crossover frequency on the tweeters. The A7 tweeter is crossed over at 2.7 kHz, while the tweeter on the Polk A9 (which is reported to have better midrange response) is crossed at 1.8 K. The A7 also has a larger midrange than the A9, one 6.5" midrange driver (ported) on the A7 compared to two 5.25" sealed drivers on the A9.


So a couple questions for anybody who has experience with these products:

-Will adding the center channel offer a significant improvement in midrange response? The tweeter on the center is a cascaded second order centered at 2.2 kHz. This is lower than the crossover freq of the speakers, so I'm hoping it will offer some improvement (I am a bit clueless when it comes to crossover frequencies on tweeters)

-How much of an improvement in midrange response does the A9 offer over the A7?

-Is there any way I can tweak the settings on my receiver to try to compensate for the lacking midrage? I ran the Yamaha automatic calibration and while it did a good job setting the speaker levels, it doesn't seem to have done anything in terms of EQ'ing. As far as I can tell there is no way to manually adjust the EQ on this receiver.


Thanks in advance for any replies. I dabbled in car audio a bit when I was younger but this is my first real experience with home HiFi.
 
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#3 ·
There could be many reasons why this is happening. You could be using the wrong crossover for the speakers. Try several different crossovers. You could also have bad speaker placement or room reflection issues. Do you have the speakers toed in and moved away from the wall? Also, having them placed to close to a A/V cabinet can cause reflection problems.
 
#4 ·
The speakers are in a relatively small room, about 12 x 18. They are positioned along one of the longer walls. I have them toed in about 30 degrees, they are only about 10 feet apart. They are about 1 foot from the wall, 16 inches from the wall if you measure on axis with the rear firing port. The rear firing port is for the woofer, however, and not the midrange. The lower end I'm getting is great although it varies as you move about the room (although that is to be expected). The speakers are also about 3 feet from the AV cabinet.


I ran the YAPO and got an out of phase message for one of the rears but wasn't too concerned about it. The speaker is wired in phase with the others and the midrange problem is present even in stereo mode.


TBH I haven't played around with the speaker positioning too much so I'll give that a shot and recalibrate, see if it makes any difference. Thanks for the tips.





(By the way in my OP I meant to say the crossover for the center channel is cascaded second order, not the tweeter itself. It wouldn't let me edit the post on my PS3)
 
#5 ·
As to phase issues you could still have a miswired driver internally which you would not know without a visual inspection. It happens more than we care to think about.


A big benefit of 2 mids allows for different x-overs to the tweeter, one lower and one higher, though I don't think they employ that on the A9s.
 
#7 ·
Well, not much luck with readjusting the speakers. Tried on axis, off axis, moving them further away from the walls, ect. Some small improvements but nothing really noteworthy.


I really don't think its a cancellation / reflection issue - such issues are usually localized, are they not? It seems more to me like the speakers, since the issue seems to be present regardless of listening position.


Ah well, maybe I'm just being too picky. These speakers do perform very well with music. Acoustic guitar sounds crystal clear, like its being played right in the room. Imaging is excellent. I don't find the highs to be fatiguing at all, as some people have reported. Highs are crystal clear and maybe a liitle shrill only on certain high notes, but that is something that might improve with break in.


Only in certain songs I think it is evident that the vocals/part of the midrange is not as "forward" as I think it should be. Most people probably wouldn't even notice - I'm not sure I would notice it myself when listening to music if I had not noticed it when watching television. On news broadcasts it becomes particularly noticeable (since it is all dialogue), voices don't sound full and don't seem to have the presence that they should have.


I still have to see how they perform with movies. I'm waiting for the center channel to come in and until I get the sub set up before I have a "movie night."


Thanks again for the replies. Cheers.
 
#8 ·
I completely missed the part about you not using a subwoofer or a center channel yet. When you add the sub your mains will be completely different sounding speakers. In a good way. Once you get the bass management dialed in your mouth is going to drop. The center channel will also add to the experience. Do you have a subwoofer already picked out?
 
#9 ·
Right there is your answer and you didn't even know it...... You don't have a sub hooked up do you? According to your above post. You are causing your AVR to work too hard and trying to get the speakers to reproduce deep bass that they aren't good at and it is choking up your midrange.


Just try this, go into your AVR set the sub to yes and set your front L&R speakers to small and 80hz cross over..... Yes I know you will lose all of the bass lower than 80hz if you don't have a sub. But listen to the speakers like that and see if the midrange is better.
 
#10 ·

Quote:
Originally Posted by Secret Squirrel /forum/post/21843187


What crossovers are you using for all your speakers.? I'm especially interested to know what crossover you have set for your mains. If it's to low or to high this could cause mid range problems.

Hi SS,


Crossover is set to 60 Hz. I had it at 80 for a little while when I first set it up but without a sub it was a little lacking on the lower end. The fronts seem to be go down to 40 with ease and without distortion. I eventually plan on doing a DIY sub with a Dayton Titanic 12" MK III, but have not put in the order for it yet.


How does the front cross over affect the mids though, if the high pass is set too low the passive x-overs will divert more power to the woofer, and will leave the midrange lacking? (proabably painfully obvious, I know, but the lower end of the frequency range is stated as 20 Hz so I guess I expected them to perform well with a lower cross over frequency)
 
#11 ·
For those speakers a 60hz crossover is a good starting point. You could try 60hz, 70hz, or even the steep 80hz THX crossover. Crossing your speakers over at approximately 60hz-80hz will make them sound more dynamic. They will also be utilized better for their strongest performance. They're rated down into the 20's but not with much authority. Trust me, when you get a sub the sound is going to improve. The voice detail will improve and so will the mid bass. I have mains that are rated down to about 25hz but I use a 60hz crossover because for 2.1 music this sounds best. For all my other speakers I use an 80hz crossover because I like it for movies. It's fast and it's a fourth order slope. My other speakers can play pretty low but the dynamics sound best not making them play to their lowest rated specs.
 
#12 ·
Thanks for the input guys, I guess I didn't expect that sub frequencies would have such a large effect on vocals.


I'll post an upadate when I get the sub hooked up, though it may be a couple weeks yet.


In my defense I've never owned a pair of towers that didn't perform well full range. I guess I shouldn't have expected four 6's to perform as well as a pair of 12's.


I think I might have to change my screen name to repair my reputation though.



Cheers.
 
#13 ·
The Polks you have are very nice capable speakers. Things have changed a little as far as speakers go. They almost all have multiple smaller woofers now. They're meant to be used with a subwoofer for the best performance. Compared to the old days when you just had a large pair of mains in a 2.0 music system. I come from those days, so we share something. Incorporating a subwoofer with your Polks will make a big difference. They will outperform the old 12's you had before in dynamics detail and clarity. You're just not utilizing them to their potential yet without a subwoofer. So don't pre judge them on their performance. You're missing the other half of the equation to really judge their sound. The sound is going to improve. It may take some time to learn and calibrate everything. It will be worth it in the end.
 
#14 ·
Reading your post, I think until you get the center channel it will be really difficult to determine if your speakers are lacking for vocals. That said, it may also take some time for your speakers to fully break-in and you also adjust to the room.


But I do agree that for bass midrange, you will want a dedicated subwoofer. It will make a huge difference for bass in the 20-60hz range.
 
#15 ·
First to OP:


I used to have the Polk RTi10 which is basically the same thing you have. I never really like the sound of them because of the design of this speaker. The cross over for the 2 large woofer to the mid range is 125 (this is quite low) for the midrange to the tweeter is 2.7kz. That is alot for the mid woofer to handle in the higher bass + mid range woofer to handle and always sounded off to me. The center has a different design and should sound better for the frequencies it plays however those playing from the towers with sound the same.


Adding a sub woofer will not address what you are experiencing IMHO. Using a sub to handle the typical low base with a cross over on the towers of at 80hrz will have not affect on the midrange and you will hardly be using the 2 large woofer in the towers.


As others have said a sub is a must for home theater but there are many towers that will sound great for music with out a sub.


"But I do agree that for bass midrange, you will want a dedicated subwoofer. It will make a huge difference for bass in the 20-60hz range"


Are you saying that 20-60 is bass midrange? That is the low end of base.


From what I have read the A9 is better because the work load is spread over 2 mid range woofers. Many users have reported that they are fairly power hungery and need an avr with a robust amp section or an external amp to "get the most out of them".


Those saying that the driving the low bass on the 2 woofers is robbing your midrange of power must have missed that your are using a powerfull external amp with the towers.
 
#16 ·

Quote:
Originally Posted by CalgaryCowboy /forum/post/21843733


First to OP:


I used to have the Polk RTi10 which is basically the same thing you have. I never really like the sound of them because of the design of this speaker. The cross over for the 2 large woofer to the mid range is 125 (this is quite low) for the midrange to the tweeter is 2.7kz. That is alot for the mid woofer to handle in the higher bass + mid range woofer to handle and always sounded off to me. The center has a different design and should sound better for the frequencies it plays however those playing from the towers with sound the same.


Adding a sub woofer will not address what you are experiencing IMHO. Using a sub to handle the typical low base with a cross over on the towers of at 80hrz will have not affect on the midrange and you will hardly be using the 2 large woofer in the towers.


As others have said a sub is a must for home theater but there are many towers that will sound great for music with out a sub.


"But I do agree that for bass midrange, you will want a dedicated subwoofer. It will make a huge difference for bass in the 20-60hz range"


Are you saying that 20-60 is bass midrange? That is the low end of base.

As an owner of the Polk rti8 and brief owner of rti-10 speakers I tend to agree with you. I was never very happy with my Polk speakers once I heard better.


As for midbass, I am not sure what your definition is. But yes it would probably be in the 50-100hz region, and I would tend to think that you would notice LFE dropping off after 60hz or so, not sure how flat the RTi-7's are to 40hz. It is hard to know where the OP is feeling that it is lacking. 60hz? 80hz? 100hz?


With a really good dedicated sub for HT, I would crossover at 80hz to start and see if Audyssey (or YPAOO) can help flatten response. You can always set the crossover higher up to 100hz it just depends on whether or not you start to localize the bass.
 
#17 ·
For home theater I also find 80hrz is a good cross over to use for most speakers. However if you are going to do that you might as well start looking else where for speakers. The RTI series strength is its large multiple low woofers. Once you start using a 80hrtz cross over to the sub with roll on and off you are basically not using the part of the speaker you paid alot of money for.

Quote:
Originally Posted by ack_bk /forum/post/21843788


As an owner of the Polk rti8 and brief owner of rti-10 speakers I tend to agree with you. I was never very happy with my Polk speakers once I heard better.


As for midbass, I am not sure what your definition is. But yes it would probably be in the 50-100hz region, and I would tend to think that you would notice LFE dropping off after 60hz or so, not sure how flat the RTi-7's are to 40hz. It is hard to know where the OP is feeling that it is lacking. 60hz? 80hz? 100hz?


With a really good dedicated sub for HT, I would crossover at 80hz to start and see if Audyssey (or YPAOO) can help flatten response. You can always set the crossover higher up to 100hz it just depends on whether or not you start to localize the bass.
 
#18 ·

Quote:
Originally Posted by CalgaryCowboy /forum/post/21843879


For home theater I also find 80hrz is a good cross over to use for most speakers. However if you are going to do that you might as well start looking else where for speakers. The RTI series strength is its large multiple low woofers. Once you start using a 80hrtz cross over to the sub with roll on and off you are basically not using the part of the speaker you paid alot of money for.

Depends what sub(s) you have and the application.


My current speakers are rated down to like 22hz and there is no way I prefer them even down to 40hz like Audyssey tries to set them at.


You still have the bass above 80hz that they Polks are used for, but you just touched on soemething. I replaced my Polk RTi speakers with a better subwoofer and a nice set of bookshelf speakers that clearly had a better tweeter design and most likely crossover and it was a much improved sound IMHO.


I would take something like a pair of Ascend 340's and the matching cetner along with a good subwoofer over the Polk towers.
 
#19 ·

Quote:
Originally Posted by ack_bk /forum/post/21843965


Depends what sub(s) you have and the application.


My current speakers are rated down to like 22hz and there is no way I prefer them even down to 40hz like Audyssey tries to set them at.


You still have the bass above 80hz that they Polks are used for, but you just touched on soemething. I replaced my Polk RTi speakers with a better subwoofer and a nice set of bookshelf speakers that clearly had a better tweeter design and most likely crossover and it was a much improved sound IMHO.


I would take something like a pair of Ascend 340's and the matching cetner along with a good subwoofer over the Polk towers.

Yeah......I agree. Hate to say it....and I really do because I think it makes me look like a jerk.....but I think the problem is with the speakers. You have a TON of nice power driving them....in fact....it could be overkill. Looks like most of the money went into the receiver and amps....and not enough in the speakers. I would spend twice or more on speakers then the receiver/amp. While those Polks are OK for HT.....they just are not 'made right' for 2 channel as already mentioned. I had some older RTI70's and they were SOOOOO muddy sounding. I bought some nice bookshelf speakers and a nice sub and and the difference is night and day. I hate to say it.....but if it's not too late, I'd return the Polks......
 
#21 ·

Quote:
Originally Posted by Dave1027 /forum/post/21844133


OP, you may be jumping the gun with this post. Wait till you get your center hooked up then let us know if you still have an issue. My guess is you won't.

I agree, and I mentioned this earlier. Start here first. If you are still not happy, you are most likely talking about changing speakers.
 
#23 ·

Quote:
Originally Posted by ack_bk /forum/post/21843788


As an owner of the Polk rti8 and brief owner of rti-10 speakers I tend to agree with you. I was never very happy with my Polk speakers once I heard better.


As for midbass, I am not sure what your definition is. But yes it would probably be in the 50-100hz region, and I would tend to think that you would notice LFE dropping off after 60hz or so, not sure how flat the RTi-7's are to 40hz. It is hard to know where the OP is feeling that it is lacking. 60hz? 80hz? 100hz?


With a really good dedicated sub for HT, I would crossover at 80hz to start and see if Audyssey (or YPAOO) can help flatten response. You can always set the crossover higher up to 100hz it just depends on whether or not you start to localize the bass.

Right, the area which is lacking is difficult for me to pinpoint or describe, but my senses are telling me it is not in the lower end. Reason being is even with the fronts on small and the crossover set to 80Hz, deep voices come through crystal clear and the higher pitched sounds/letters (like s's and t's) being handled by the tweeters are also very pronounced, but something in the middle is missing.


I didn't have the opportunity to audition the speakers before puchase, they were not a floor stock item. I listened to some music tracks over some A5's in the store and I thought they sounded adequate. To be honest if I would have gotten a chance to listen to the A7's I'm not sure it's something I would have noticed in the store. The speakers seem to perfom wonderfully with music, it is with HT where it tends to become more evident. And even then it seems like something that takes a little time to notice.


As ack_bk has mentioned, I guess I will have to wait for the center and see what type of difference that will make. Raising the crossover freq. seemed to offer some improvement as well.


I had read in some reviews that the A9 had a better midrange, so I expected some compromise in the midrange section, I just didn't expect it to be so evident in the area of vocals. I guess with HT speakers I expected the vocals to be more forward.


Well, either way, I think the speakers perform well with music, and hopefully the center will help with HT...
 
#24 ·

Quote:
Originally Posted by Mark_1042 /forum/post/0


The speakers are in a relatively small room, about 12 x 18. They are positioned along one of the longer walls. I have them toed in about 30 degrees, they are only about 10 feet apart. They are about 1 foot from the wall, 16 inches from the wall if you measure on axis with the rear firing port. The rear firing port is for the woofer, however, and not the midrange. The lower end I'm getting is great although it varies as you move about the room (although that is to be expected). The speakers are also about 3 feet from the AV cabinet.


I ran the YAPO and got an out of phase message for one of the rears but wasn't too concerned about it. The speaker is wired in phase with the others and the midrange problem is present even in stereo mode.


TBH I haven't played around with the speaker positioning too much so I'll give that a shot and recalibrate, see if it makes any difference. Thanks for the tips.



(By the way in my OP I meant to say the crossover for the center channel is cascaded second order, not the tweeter itself. It wouldn't let me edit the post on my PS3)

Try toeing them in less, maybe only 10 degrees, and pull them out from them back wall a bit more. The combination of doing that will reduce the highs, and lows at the same time. You may need to turn the volume up to make up for the perceived reduction in output, but it should even the response a bit
 
#25 ·
When I first had my polks I really like them. It wasn't until I learned more about audio and heard more that I became dissatisfied. Something was just missing. For me it was 2 channel music I did not like the mid range in (muddy). For HT with a center I really could not tell with sub, center, and surrounds playing. I have always been more critical with music and tend to taylor my system to that.
 
#26 ·
I am also new to this forum and looking for any advice possible. First I would like to say that IMO mid range and vocals are very user dependant. To me really bright mids and vocals take away from the listening experience especially when considering music. I stumbled on this thread trying to find out if there was a fundamental problem with the A7's as I have blown my 6.5 inch driver inside of 3 months on one channel. At this point I hope that it was a bad driver but my gut feeling is that there is too much expected of this driver at high volume. Up until it STB i was REALLY happy with these speakers.Of course Polk is replacing it but I hope that this is an isolated incident. Without trying to hijack this thread can anyone tell me if they have experienced repeated (or any) problems with this driver?


Thanks

Eric
 
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