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Special Edition Cornwall IIIs and the Quest for Bass


ultruh

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So I'm having some really weird issues in my new house with my new Cornwall IIIs.  I have a game room in my new place with high vaulted ceilings (room is about 15x25).  Linn Sondek LP12 (Adikt), Naim 110 and NAC42.  When I first hooked up the CWs, I had them about 6-12" off the wall and about 6 feet apart on carpet.  Bass was absent.  I pushed them against the wall and checked the cables to make sure phase was good.  The bass improved, but still isn't where it should be.  As the speakers are brand new, I decided to put some hours on them before really making any more changes.  

 

Last night, I'm changing the AC return vent in the back of the room near the ceiling.  On top of the ladder (about 10 feet off the ground), the bass was near perfect.  So strange.  I don't know what happened to get it directed up there, but somehow the sweet spot is in the back corner of my ceiling.  I came off the ladder: bass was gone.  Moved my couch to the back of the room.  No difference.  

 

So, here is my plan: 1) replace current audio cable with new Audioquest bi-wire cables, 2) move CWs to the corners of the room, 3) add spikes(?).  I'd love to hear your thoughts.   

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5 minutes ago, jimjimbo said:

6 feet apart is much too close.  Move them to the corners.

I agree.  That's my plan.  Need new cables so they will reach the corners.  Ordered this morning.

 

5 minutes ago, twk123 said:

Where is your listening position? You might be in a null in the room. If you are exactly in the middle of the room, bass will be virtually non-existent.

I've tried about 2/3s back and all the way against the back wall.  The change hasn't made a noticeable difference.  

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I recommend using REW's "Room Sim" facility to predict the bass response at the listener's position given the room dimensions (length, width AND height), loudspeaker/subwoofer positions (x,y, and z within the room) and listener's position (ditto).  I think that you'll see why you're having bass problems. 

 

The cool thing about REW's Room Sim is that you can continuously move around the loudspeakers or the listener's position to instantaneously see the frequency response. That's a pretty effective time saver and visualizer of the problem.

 

Chris

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15 minutes ago, Chris A said:

I recommend using REW's "Room Sim" facility to predict the bass response at the listener's position given the room dimensions (length, width AND height), loudspeaker/subwoofer positions (x,y, and z within the room) and listener's position (ditto).  I think that you'll see why you're having bass problems. 

 

The cool thing about REW's Room Sim is that you can continuously move around the loudspeakers or the listener's position to instantaneously see the frequency response. That's a pretty effective time saver and visualizer of the problem.

 

Chris

Thanks, Chris.  I'll try that.  You're just down the street from me.  I'm in NRH.

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22 minutes ago, Chris A said:

I recommend using REW's "Room Sim" facility to predict the bass response at the listener's position given the room dimensions (length, width AND height), loudspeaker/subwoofer positions (x,y, and z within the room) and listener's position (ditto).  I think that you'll see why you're having bass problems. 

 

The cool thing about REW's Room Sim is that you can continuously move around the loudspeakers or the listener's position to instantaneously see the frequency response. That's a pretty effective time saver and visualizer of the problem.

 

Chris

 

I've not used REW's "room sim" but most I have used assume a rectangular room so if you have a vaulted ceiling it's predictions could be much different than your actual acoustical conditions. 

 

miketn 

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1 hour ago, mikebse2a3 said:

I've not used REW's "room sim" but most I have used assume a rectangular room so if you have a vaulted ceiling it's predictions could be much different than your actual acoustical conditions.

 

Thanks for that advice, Mike.  However, since you haven't seen or used the room sim, I think that your opinion will likely change when you see how it can be used in doing parametrics--and the degrees of physical dynamics it's simulating.  Playing continuous parametrics with the ceiling height by moving the ceiling height value up and down while continuously watching the response plot will give you an intuitive feel for the frequencies affected (largely irrespective of the vertical ceiling height).

 

"Highly recommended": I didn't recommend it without realizing what you point out, above.

 

Chris

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7 hours ago, ultruh said:

So, here is my plan: 1) replace current audio cable with new Audioquest bi-wire cables, 2) move CWs to the corners of the room, 3) add spikes(?).  I'd love to hear your thoughts.   

 

#2 is well worth a try.

#1 and #3 are very unlikely to address the issue your describing.

 

7 hours ago, ultruh said:

 I pushed them against the wall and checked the cables to make sure phase was good.  The bass improved, but still isn't where it should be.  As the speakers are brand new, I decided to put some hours on them before really making any more changes.  

 

As a quick test to eliminate polarity issue (ie: external or internal miswiring) reverse the speaker wire polarity on one of the speakers and note if bass increases or is reduced.  (I suggest using something with good low frequency content or low frequency test tracks).

Note: the closer you have the speakers together during this test the less the room acoustics will dilute the effect of in polarity or out of polarity woofers.

 

7 hours ago, ultruh said:

 I have a game room in my new place with high vaulted ceilings (room is about 15x25).

 

7 hours ago, ultruh said:

Last night, I'm changing the AC return vent in the back of the room near the ceiling.  On top of the ladder (about 10 feet off the ground), the bass was near perfect.  So strange.  I don't know what happened to get it directed up there, but somehow the sweet spot is in the back corner of my ceiling.  I came off the ladder: bass was gone.  Moved my couch to the back of the room.  No difference.  

 

How high is the ceiling form it's low point intersecting the wall to it's high point..?

What exactly is it shape (ie: "V"shaped for example)? 

Are the speakers located on a wall parallel with the angled part of the ceiling..?

 

Can you describe any openings (ie: doorways.... etc......) and their locations...? Pictures or diagrams of the room would help us to understand your situation better.

Is the room except for carpeting very live (ie: hard reflective surfaces...?

 

 

miketn

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8 hours ago, ultruh said:

 

Spikes won't do squat for bass; don't even bother. Neither will fancy cables. It's the new house with the new room with the VAULTED ceiling.

 

Your best bet is to mount the couch 10' off the floor where you were on the ladder. ;)

 

Seriously; the acoustics of the room are doing something to cancel the bass. First thing I'd try is to place the speakers against the adjacent walll, JUST AS AN EXPERIMENT. If you notice a change then it's a speaker placement issue. If not, then it's the room shape and dimensions. For the next experiment, place the speakers in a room with no vaulted ceiling and see what happens. I think the speakers aren't pressurizing the room because something is happening caused by the vaulted ceiling or other room dimensions.

 

Another experiment you should try is to stand tight with your head backed into a corner of your room. In fact, try this with all 4 corners. As you listen to your music you should hear the bass reinforced when standing this way. It's merely to show you that bass response can vary greatly depending on your listening position, as you discovered when on the ladder.

 

If I may recommend an excellent CD for testing bass frequencies in your listening environment-seek out a copy of Boston Acoustic's Rally Bass Collection. The Collection consists of 3 discs with each disc focusing on a particular type of bass sounds. Disc 1's tracks focus on "Extension, Attack, and Musicality". Mostly a lot of low bass cuts from the Neurodisc catalog.

 

Disc 2's tracks from Rykodisc's catalog were "selected  for testing detail, musicality, and transient response".

 

Disc 3's tracks from Windham Hill artists presents "Well controlled bass... to make sure your system is in balance".

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Thanks, gents.  I've ordered a copy of that BA Rally Bass CD.  I know it is not a source issue (played Doin' Time - uptown dub by Sublime on CD and Vinyl and the issue was the same), so I feel comfortable eliminating that possibility.  I agree that "fancy" cables won't make a huge difference.  However, I don't have a length of my Naim cable long enough to reach the corners, so I got some 10 foot long AQ cables to allow me that possibility.  

 

The vaulted ceiling is shaped liked this (only upside down): \_/. Flat at the top.  I will continue to re-position and make adjustments throughout the week and give y'all updates.  Thanks again for the input. 

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I can tell you I had a vaulted ceiling that drove me crazy.  The best speaker location for clear and even bass destroyed imaging (singers voices sliding all over the place) and the best location for imaging created lousy peaks and nulls.  Also, corners are not always the answer but you should try if you never have.  Which part of the vaulted ceiling are the speakers located?  How high is the shortest and the highest points of the ceiling?  I'm hoping you don't have part of a cube there.

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You may have to add sound absorbing materials to walls ceiling etc.    Try a cardboard box under the speaker.   Mine worked best at about 12 inches.   I did not see but have you tried outside but angled in at 20-30 degrees?   Mine sound their best angled in about 20 degrees or so.

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On 5/23/2017 at 1:35 PM, avguytx said:

Sounds like a different room is in order. ;)

If I could put them back in the basement of my old house, I would.  That spot was dyno-supreme for acoustics.  Alas, this is the only room that works in my new house.  

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UPDATE:

 

I put them in the corners with new cable and the bass drastically improved.  It hit hard enough to give me that nauseous feeling (in a good way).  I can tell that they would be even better in a different space, but they are great where they are now.  I will continue to tweak by experimenting with dampeners, etc.  Thanks again for all of the help.

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