Polk RTi's and bass

BjornB17

I know this has come up a million times before but the search function hasn't been helpful in finding the old threads so i'll bring it up again:

As well all know the Polk RTi's are great speakers, but a bit bright. Although the RTi10's and RTI12's have those nice 7" woofers, they still don't make a lot of bass.... or atleast they are overpowered by the high end.

Well, yesterday i was setting up my speakers for bi-amping now that i have an Emotiva UPA-7... i will use 4 channels from it to bi-amp the RTi10's i have which will allow for up to 300 WPC in stereo mode. I decided to hook up just the terminals for the low end of the speakers, leaving the jumper off and not connecting the second terminal for high end.

Wow.... those speakers are capable of putting out some serious, good sounding, loud, tight bass.

I then changed things up and connected just the high end to the amp. It seems like there is atleast a 10 db difference in my perception of what the lows and highs sound like at the same volume setting on my pre-amp.

I really prefer the sound of the bass of the RTi10s over that of the separate subwoofer I'm using... atleast for music as it sounds much tighter.

My question is... is the frequency response of these speakers really that skewed towards the higher end? The Polk specs rate them as +-3db over most of the human hearing range but my experience seems to indicate that this isnt the case unless the high end is +3db and low end is -3db.

How can i bring the volume of the bass in line with the high end? I assume i could buy an Emotiva UPA-2 (which has adjustable gain knob) and connect it to the high end and lower the gain on it to be below that of the UPA-7... but is there an easier, cheaper way?

Thanks in advance..

apphd

I am not very knowledgeable on this but I'll toss this out so I can learn along with you. I think this is a combination of things, I think it is just the physics of how we hear frequencies (I'm thinking that the high end just appeared to be +10db louder than the low end connection) combined with taking a lot more power to drive low freq. to an equal perceived level so there will probably be some difference. This is just my "thinking out loud" idea. What are you using for a pre pro? Only solutions I can think of are:
1. add a sub
2. adjust the treble/bass settings
3. try a different amp which may have a different sonic quality although most claim to be neutral
4. try a different pre pro.

Hope some others will add to this as I am always interested in getting rid of some of my mis-conceptions on audio.

LessisNevermore

Do you still have a disparity when running off just 2 channels of the amp? (i.e., not bi amping)

edit.) Maybe you can set up a zone 2 on your receiver for the highs or lows. You would then have independent control of the levels for each.

BjornB17

apphd wrote: »

I am not very knowledgeable on this but I'll toss this out so I can learn along with you. I think this is a combination of things, I think it is just the physics of how we hear frequencies (I'm thinking that the high end just appeared to be +10db louder than the low end connection) combined with taking a lot more power to drive low freq. to an equal perceived level so there will probably be some difference. This is just my "thinking out loud" idea. What are you using for a pre pro? Only solutions I can think of are:
1. add a sub
2. adjust the treble/bass settings
3. try a different amp which may have a different sonic quality although most claim to be neutral
4. try a different pre pro.

Hope some others will add to this as I am always interested in getting rid of some of my mis-conceptions on audio.

Thanks for the input - here are my responses to your suggestions:
1. I have a sub but would like the 10's to handle more of the bass since it seems to be tighter and better sounding than what my sub can produce
2. raising the bass setting makes it sound boomy... not the same clean bass i heard when conneting the woofers on their own at louder volumes. lowering trebble makes it sound muddy... instead of having the same clariy at a lower volume it instead just sounds dull
3. hk-254 and Emotiva UPA-7 are considered to be warm so if anything they are helping rather than hurting. for a while I was using an Emotiva LMC-1 as a pre-pro rather than the HK-254. The LMC is a bit brighter (or not as warm as 254) but overall results were similar... just seems to be an inherent trait of the RTi's
4. used both LMC-1 and HK-254 with similar results

BjornB17

LessisNevermore wrote: »

Do you still have a disparity when running off just 2 channels of the amp? (i.e., not bi amping)

edit.) Maybe you can set up a zone 2 on your receiver for the highs or lows. You would then have independent control of the levels for each.

yeah it sounds basically the same either way.... perhaps slight improvement with bi-amp especially at higher volume but overall tonal characteristics are the same regarless if i'm bi-amping or single-amping with UPA-7 or just using my receiver to power speakers.

cnjvh

apphd wrote: »

I am not very knowledgeable on this but I'll toss this out so I can learn along with you. I think this is a combination of things, I think it is just the physics of how we hear frequencies

This is exactly right. The speakers measure mostly flat across their frequency response but humans don't hear that way. This is the reason for C weighting on SPL meters. In the old days manufacturers would design a bass hump into the speaker to make it sound more natural but today's preference amongst the audio community is for a measured flat response.

Your solution is to keep the biamping in place and increase the volume of the amp driving the low frequency terminals until it sounds balanced. you could also use a c weighted meter and pink noise (measuring first the low terminals only and then the high terminals and make and adjust your amp settings until they read the same on the c weighted meter. That should give you a perceived flat response and a measured response with a hump at the low end.

cnjvh

oops I just read that my solution means you have to buy other gear than you meant to. Not sure of any other way...

BjornB17

cnjvh wrote: »

oops I just read that my solution means you have to buy other gear than you meant to. Not sure of any other way...

thanks for the explanation... i didn't know that we hear it different than an SPL meter... that would explain it.

As for buying more gear.... hey its a good reason to get a new toy to play with

Tommytutor

I have the same issue myself, different brand of speaker though. Maybe someone could chime in on this. Could resisters be used as links between the high and low terminals to pad down that half of the crossover? In essence connect the cable from the amp to the low freq. inputs on the speakers with the resisters strapped to the high freq. inputs. Or maybe an L pad could do the same thing.