Totally confused about those Polk RTi 8's with my Yammie's 2500
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New member Username: DayterPost Number: 1 Registered: Jan-07 | Hi everybody.. Hello to everyone .I've been following your expertized specialized topics , reviews , comparisons regarding many receivers capabilities and have been really pleased with your in depth detailed knowledge. (N.b: The same topic I've posted in another forum to collect opinions and thoughts, yet uptill now I'm not completely satisfied with the replies.) It's my first thread over here , so please forgive my reletive longetivity in explaining my vague case.. (N.b: The same topic I've posted in another forum to collect opinions and thoughts, yewt untill now I'm not completely satisfied with the replies.) I've picked up in December thy Yammie's kong performer Rxv-2500 at a clearance sale in my local Tweeter store. I couldn't be much happier with this unit extremely superb processing/decoding capabilities , yet have been searching for a while for thy best speaker brands and models which would perfectly match its Power amplification abilities. Finally ,after many readings , studies and researches I decided to go with thy Polk's RTi8's for my fronts. I went a day before to my local audio speciality shop for listening to this RTi series , being motived by the many positive reviews , impressions and opinions loaded in here , and ... God.. I was totally shocked.. I concentrated mainly on auditioning those dual front Rti 8 channels , for a Dvd demonstation material carrying some late demos of King Kong , Mr.and Mrs.Smith and others , being processed by a Marantz 8500 ( which lies in thy same league with my Yammie's) , and thy results were completely disappointing! Yeah , sound produced by these was somewhat clear , detailed , crisp with nice mid - discrimination , Yet , when I''ve asked 'em to crank thy volume up to a value of 0 db (75% of this marantz volume caliber) , everything began to lose its sharpness to a harsher harder sound types with unbearable degrees of turbulence , disturbance , and noisy outcomes cerainly with losing many details .. I never expected this experience to happen.. I've been told by many that these Rti 8's particularly would easily reach because of their ultra efficiency levels the maximum values of any mid-fi receiver volumes scale calibers wthout being strained at any degree and by any means... I've been told by thy managing director that many auditory circumstances should be replaced , and many fixations should be done to thy total room acoustics , and some modifications to the whole system constituents to get those play at most accurate loud levels.. I know he's essentialy right ,and I do appreciate what was he trying todo inorder to enhance and refine thy whole thing with pillows , bags , angles , positions and so on. Yet I believe that all of these factors were just responsible for a limited degree and to a certain extent , and the major percentage of this horrible noise appearances at 3/4 levels of thy amp section output is mainly caused by those Rti 8's I've been waiting for a long time ago , even if this caliber value was producing extremely loud sound because of the respectable efficieny range of this model. Sorry have to go , and I'll be telling you what I ve felt when listening to something stunningly different at thy same shop.. Please tell me your thoughts.. Are these really normal findings with those Rti 8's..??! I never thought they'd act this terrible way at loud levels even before reaching the zero db value of thy huge marantz 8500.. I'm out of sync.  |
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Silver Member Username: StefanomVienna, VA United States Post Number: 313 Registered: Apr-06 | Well, 0dB is 100%, not 75% of most receivers volume abilities. Going beyond, while allowed on the volume control, that risks clipping. And yeah, most speakers won't sound good at that point. However, if the speakers do not go up to a volume level you would like, its time to find more efficient models. Try out something from Klipsch perhaps. |
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New member Username: DayterPost Number: 2 Registered: Jan-07 | Thanks Stephen. Going beyond, while allowed on the volume control, that risks clipping. And yeah, most speakers won't sound good at that point. I know thy fact , yet I was vigorously motived by thy incredible reviews to thy Polks in general , and specially to those Rti 8's. Even more , many experts ,specialts and consultants have been saying everywhere that those in particular are extremely efficient and power hungry , so better use even an external amp to drive them at their needed paces , and those amp sections embedded in thy marantz 8500 (or thy yamahas 2500 which is in thy same league )though they're one of thy most powerful , they wouldn't be enough to give 'em the amount of fuel. Is thy problem lies within those amp sections , aren't capable of driving those Rti 8's?? Or with the loudspeakers themselves , being reached their absolute maximum , so couldn't get any louder except with some degrees of distortion , clipping and disturbance ?? Both assumptions are killing , yet the the first would be more in line with what many enthsuthiasts suggested about those models. Help please.} |
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Silver Member Username: StefanomVienna, VA United States Post Number: 315 Registered: Apr-06 | I'll try to make it simple what happens. Each speaker has a spec known as Sensitivity. This is effectively the average output the speaker will have with a 2.83 volt input (which is 1 watt into an 8 ohm load). Every time you double the wattage, you gain 3dB. The Polk is rated in that spec at 90dB and presents an 8ohm nominal load. The Marantz can put out 110 watts at 8 ohms. When you apply what I said above to this, it can put out roughly 110dB of volume (a little more for peaks). Now, the two limiting factors are the capacity of the speaker, and the power output of the amplifier (much more commonly the problem). Both cause distortion and will destroy the speaker. Given what you've told me, I'd tend to believe that the amplifier/receiver was at the end of its rope. |
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New member Username: DayterPost Number: 3 Registered: Jan-07 | Thanks Dude.. I know about thy sensitivity /efficiency issue , and was totally expecting much more sound pressure levels with those RTi's without even reaching thy amp limits. And that's why I was extremely shocked by thy outcome , as I've followed other's experiences with their top-end Yamahas'2500 , denon's 3805's , marantz 8500's driving those so easily at thy amp peaks without clapping or crackling sound productions. Weird ..Isn't it?? So , you suggest using those with an outboard spearate amp inorder to perfectly match their full capacity and maximum potential?? Thanks a lot .  |
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Silver Member Username: StefanomVienna, VA United States Post Number: 318 Registered: Apr-06 | I would try more efficient speakers if you really need more volume. Try the Klipsch Reference line out. |
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New member Username: DayterPost Number: 4 Registered: Jan-07 | Hmm. So how do you describe and explain what's happenend with others ? How they were simply reaching their amps maximums without hearing anly slight distortion character ? In other words , how could they suggest even implementing separate powerful amps to drive those ultra power hungry Rti 's(as they've called 'em) , in case I've heard them completely suffering , straining and crying at the lower receivers amp section classes ??!! Something strange ,which is really driving me mad.  |
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Silver Member Username: StefanomVienna, VA United States Post Number: 319 Registered: Apr-06 | Others probably aren't pushing their amplifier to the maximum because it generally gets plenty loud without doing so. They suggest outboard amplification because you want more volume. Thats one way to do it. The other (generally cheaper way) is to get more efficient speakers. |
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New member Username: DayterPost Number: 5 Registered: Jan-07 | Then , based on your scientfic classification for responsible factors of appeared clipping , I would conclude the following : A separate more powerful amp won't do anything (in terms of loudness) to a loudspeaker set that have reached its full potential with audible distortions with a step-down receiver embedded amp . Isn't true ? So people suggested implementing a separate amp were completely wrong (though I pretty much know they're experts) , about this assmption particularly. This in case the defect is with the speaker limiting factor . Secondly , if the defect is with the amp section , being underpowered in relation to thy polks , then why did they say that they were reaching their max. ( I'm sure of it ) volume dial levels without any disturbance or turbulance appearances in sound produced ?!. Sorry being boring , but I'm waiting for some detailed information from you. Grateful.  |
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Silver Member Username: StefanomVienna, VA United States Post Number: 320 Registered: Apr-06 | If a speaker has reached its power handling limits, adding a more powerful amplifier won't help you. This is a correct statement, however I doubt it applies in your case. If the speaker has not reached its limits, then a more powerful amplifier will help, but not as much as you think. You need to double the power output to gain each 3dB. Now if your buddies are throwing the volume to max in their setups and not hearing any distortion, either the receiver has a limiting feature in it so it doesn't kill itself and your speakers, or they're deaf. If they play with extremely high volumes like that regularly, then they may very well be deaf. The possibility also exists I suppose that the Polks you demoed were already damaged through abuse. |
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New member Username: DayterPost Number: 6 Registered: Jan-07 | Lol.. Hmm , I'd probably try to investigate their ear drums integrity .  I'm probably feeling what you've lately reached. Those Polk's might be definately damaged , defective or B-stocked. But how to make sure of it. I couldn't describe it in terms of audio corresponding SPL referance levels , yet what I've experienced when listening to these is nothing short of shocking. They weren't that loud I used to hear at my outdoor movie theatres . Take care , I'm not pointing at the huge dynamic impact , the giant deep extension , the incredible clarities , purities , accuracies and precisions ,or any other way of discrimintaion between an apartment acoustics and a professional cinema one. What I mean is loudness. Far away from what I've been acustomed to listen at , and far away from what I've been dreaming of based on others reviews. How to know ? |
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Silver Member Username: StefanomVienna, VA United States Post Number: 321 Registered: Apr-06 | Bring an SPL meter? |
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New member Username: DayterPost Number: 7 Registered: Jan-07 | Then ? What would be my references ? Btw ,I'll probably take my new Yammie's 2500 to test 'em at . You know it's rated at a 130 wpc (20hz-20khz) . So , which values should I read on thy SPL meter , when matched with these 90db rated Polks , if sound produced is at its maximum distort-free character ? |
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Silver Member Username: StefanomVienna, VA United States Post Number: 322 Registered: Apr-06 | Bring an SPL meter to the movies and measure the maximum output you get there (since that seems to be your reference). Then at least you'll know what you are craving. Then you can compare what the Polks do on the same material, within their limits. |
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New member Username: DayterPost Number: 8 Registered: Jan-07 | What are you expecting ? And what should this Yamaha 2500 /Polk Rti-8 combo sound like , reaching which Spl levels theoritically? |
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Silver Member Username: StefanomVienna, VA United States Post Number: 324 Registered: Apr-06 | A lot of it depends on room placement and setup, but a rough estimate of the Polks volume ability would be 110dB, which is by no means low. |
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New member Username: DayterPost Number: 9 Registered: Jan-07 | A 110 db distort - free ?? I doubt they'd reach it safely. |
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Silver Member Username: StefanomVienna, VA United States Post Number: 327 Registered: Apr-06 | They should, assuming your receiver isn't weaker than it claims to be, and assuming the Polk is as efficient as it claims to be. |
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New member Username: DayterPost Number: 10 Registered: Jan-07 | Hmm. I see. So what's a normal person ear sensate and perceive at this pressure level in particular ? What does a sound volume value of so represent relatively to listeners , if this makes sense ??! |
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Silver Member Username: StefanomVienna, VA United States Post Number: 329 Registered: Apr-06 | http://www.myhometheater.homestead.com/splcalculator.html Note the SPL scale under the calculator. |
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Bronze Member Username: DayterPost Number: 11 Registered: Jan-07 | So , a 110 dB is representing acoustically sound produced fro a Jet flyover at 300 m . Hmm . I sear it didn't reach it purely. Something missing , but I'll make sure with thy meter. Thanks a lot dude . |
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Gold Member Username: NuckPost Number: 5556 Registered: Dec-04 | The yamaha delivers about 65wpc before running out of gas. |
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Gold Member Username: KanoBC Canada Post Number: 1132 Registered: Oct-04 | I have had Polk Rti8s for a few years now. Paired with a Harman Kardon AVR430 receiver I have experienced exactly what you are describing. The problem is the bass output of these speakers, THAT'S where they're power hungry. I bet if you turn the bass down in the tone controls the treble and midrange will improve greatly. I bought a 200W/2 power amp to drive the Rti8s and this greatly improved the bass output at ALL levels. This I can't explain. I can say however that in bass heavy recordings I can max out the power amp to where the red lights start coming on and the sound level is not even that loud. I can guarantee a Yammie 2500 will not get the most out of these speakers without an external amp. |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 2007 Registered: Feb-04 | 90 dB at 1W corresponds to 110 dB at 100W only at the rated distance of 1 meter! Use the SPL calculator above to get better in-room indication, and remember that the absolute peak SPL will only occur on peak parts of the recordings. Don't expect a constant 110 dB in your room from those Polks! For example, my speakers have a sensitivity of 105 dB, yet I don't reach constant SPL of 125 dB. It's probably closer to 115 dB without fear of hitting up against hard limits. |
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Silver Member Username: StefanomVienna, VA United States Post Number: 330 Registered: Apr-06 | But then there is room reinforcement, etc. Amusingly enough, when I ran it a few days ago, the final calculation did come to roughly 110dB though with 5 speakers at something like an 8 foot distance. As far as SPL peaks go, it mostly depends on the material being played (rock vrs classical for example). In any event, most receivers should have a bit extra headroom for a few millisecond bursts of a few hundred watts for peaks. |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 2008 Registered: Feb-04 | Sure, but not long enough to get that needle up on the Radio Shack meter. |
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Bronze Member Username: DayterPost Number: 12 Registered: Jan-07 | Back mates. Sorry being late , was quite busy at work. Hey Kano , so you've faced thy same distortion issue with your RTi's at 3/4th of the Harman's volume caliber ?? And if so , How could you concluded that thy main cause was underpowering of Rti's bass production ?? And finally , what's thy main discrete cause detector of any distortion issue ?? How could you definately say that this case is Underpowering or overpowering? Which is which ? Is it your amp section running out of fuel ? or your speakers are jsut being over-fueled ? Both cause distortion , disturbance in sound produced. But how to scientifically know ? |
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Platinum Member Username: Project6Post Number: 12661 Registered: Dec-03 | Have you looked at your source material? Does the distortion always happen at the same point in your source? Try this source on a different player and check for the distortion. I've had issues of this manner before and I found out the the recording was less than stellar. |
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Bronze Member Username: DayterPost Number: 13 Registered: Jan-07 | Hey Berny .. Nah.. It isn't thy source.. It's when I do crank up thy voume to a certain level (usually at 75% of its total caliber) , distortion appears , with any source , for any signal.. I'm just trying to figure out how to , at a first look , determine which is which.. To discriminate between the two possible distortion causes. |
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Bronze Member Username: DayterPost Number: 14 Registered: Jan-07 | Hey Berny.. Nah . it isn't the source , nor the signal. It's just when I do crank up thy volume up to a level near 3/4th of its total caliber , and was trying to figure out the cause of it. Which is which ? Generally |
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Gold Member Username: NuckPost Number: 5597 Registered: Dec-04 | Have you checked the source output voltage to the receivers input sensitivity? The source output may exceed the input sens, driving the amp section to premature maximation(sic), causing distortion at higher levels. Again, the Yamaha is not a strong performer at higher levels, it has no guts for that kind of horseplay. |
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Platinum Member Username: Project6Post Number: 12663 Registered: Dec-03 | I read more of the thread, which I should have done in the first place  I have ran into that same situation before, but the combination was nothing as good as HK/Polk pairing. It is a much weaker receiver coupled to Athena ASF2. The distortion was apparent before maxxing out the volume vontrol. The receiver could not keep up with the volume music demands and is manifesting itself in the speakers. I used the pre-outs of the weak receiver, used it as a pre/pro, and connected mono-block amplifiers. The problem effectively disappeared and I was able to max out the volume without any discernable distortion. The weak link was definitely the power feeding the speakers and a more robust power amp was able to keep up with the demands. The loudness, as it were, was not any more affected, just the disappearance of the distortion. |
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Bronze Member Username: DayterPost Number: 15 Registered: Jan-07 | The loudness, as it were, was not any more affected, just the disappearance of the distortion.\i Wow..That's exactly what I meant from thy very beginning , and hoped to listen others experiences around. Though , I was dreaming of this Yammie's 2500 (=marantz 8500) I do own to reach my desired 'horseplay' levels without straining , based on many positive expert reviews given to its amp section capabilities. Now , everything's totally clear. But , my last question would be: When I tried once to connect my 35 watts crappy old grandma bookshelves speakers to a latest technologized 130 watts perchannel receiver , distortion appeared at an early location on thy dial. I know both cause distortions to sound produced: 1-Weak speakers reaching their absolute maximum potential. 2-Boisterous speakers being overdriven by a weaker amp. How to differentiate between both types , to make sure which is responsible of it.. Totally thankful guys.} |
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Gold Member Username: NuckPost Number: 5598 Registered: Dec-04 | That's a better power supply at work. |
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