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Discussion Starter #1
I am still confused after reading the manual and John's responses.


I have a DVD-A player.


My Receiver is a Yamaha DSP-A1 and I have it's pre-outs feeding a 2 channel Parasound AMP.


The Yamaha's internal amps are connected to the Center and Rears while the Parasound is connected to the Fronts.


My SUB is a Velodyne FSR-12 - it's the powered, active servo type.



Do I connect the ICBM as described on page 4 of the Manual OR on page 6?


IE. Connect the DVD-A player to the ICBM and then to the Yamaha

OR

Connect the DVD-A player to the 6 analogue input's on the Yamaha and connect the ICBM between the Pre IN and Outs on the Yamaha.


Thanks for any responses.


Joe
 

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How you connect the ICBM to the DSP-A1 has to be beased on what you are trying to achieve.


As I recall, the DSP-A1 is one of those rare products that can take the 6-ch analog inputs and digitize them. This makes the full processing capabilities of the DSP-A1 available, whether effects processing or bass management. Since this also means it takes care of time delay and gain trims, it is a better solution than the ICBM can do alone. If you insert the ICBM between the preamp and power amp sections, the level trims and time settings of the DSP-A1 will affect the signals feeding the ICBM, which can degrade bass quality to some degree. I'm not sure the greater flexibility in crossover frequencies ICBM offers outweights this.


If you only want to process the DVD-A signals, and then somehow not use the DSP-A1's bass management for the 6-ch input signal (I believe this is also an option--please check), then connect the DVD-A into the ICBM, then the ICBM into the 6-ch input of the DSP-A1. To the extent that the ICBM's flexibility gives better results than the internal DSP-A1 process, you'll gain an improvement. It might even allow you to bypass the DSP-A1 A-D altogether, but you'll need to check that. If bypass means losing channel gain trims, you probably don't want to do that, because the channel trims in the DVD-A player need to all stay at 0 dB in order to give the ICBM what it needs for optimal results.
 

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Discussion Starter #3
Roger,

Thanks for the reply. Now I have to go absorb what you are saying and re-double check the manual on the A1. I just got the ICBM delivered today.


The manual on the DSP-A1 only has 1 page about the external analogue inputs and all it says is that it is for an external processor. I can see from the schematic that using the External inputs bypasses the DSP section.


To enable those inputs, you set the receiver to "External Decoder IN" and the receiver then ignores all bass and time management settings. I could be wrong so I will re-check that.


What I am sure of is that the Center channel is getting full frequency when I set it to External Decoder IN with the DVD-A player connected and my SUB has to be turned up in volume when calibrating with VE.


My fronts are NHT 2.9's so they are set to large anyway and my rear's are NHT 2.5i's so they are set to large also.


I was hoping to tame the amount of bass going to the rears as they only have 8" drivers as well as getting the Center back to 'small' and the SUB back to reference levels for ALL source material.



Hence my question about putting the ICBM between the pre-amp and amp section. I am trying to use this ICBM for more than my DVD-Audio player.

Also, the SUB out on the A1 is fixed at a 90Hz crossover and I want to lower it.


Your comment about time management 'messing' up with the ICBM is something I did not think about particulary for the Pro-Logic modes when watching movies from my Sat receiver.


Also, due to the odd shape of the back of the room, the rears are not equal in distance from the sweet spot so they are set to +2db and +1db. You made me realize that this is going to be a problem.


I was hoping for a simple answer like hook the ICBM as described on page x so as to avoid having to mess with all that cabling to try it both ways.

Not so lucky:)

Now I have to RTFM and if you have seen the manual on the DSP-A1, it is a very detailed but complicated thing.


When I get this figured out I will post my results since 1) You took the time to answer me and 2) other's could benefit from what I find out.


I suspect that I may only be able to utilize the ICBM for DVD-Audio and let the Yammy due it's thing on DTS and DD material via the coax digital in.


Thanks,

Joe
 

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Joe: (I run an ICBM for full time bass management between my Denon 3802 and a Carver 5 channel amp.)


Does the A-1 have a complete 5.1 set of pre-amp outs and power amp ins? If so, then you can try either setup you describe. And in the end, that is exactly what I think you should do. (Unfortunately, this does mean hooking up 6 more interconnects!)


Obviously, if you place the ICBM between the DVD-A player and the 5.1 analog inputs, you will get a full analog signal path, along with all of the benefits that a flexible crossover can give. The down side is that if the ICBM gives a better system bass synergy than the Yamaha's 90 Hz approach (and it's almost a slam dunk that it will), then it seems like a darn shame if you can't go ahead and always use the ICBM for all of your bass management.


As far as the concern over the ICBM's bass when using it with delayed center and surround speaker signals...several have mentioned it in discussions about the ICBM (not to mention Mr. Dressler (above) from Dolby and Outlaw Audio themselves.) All I can say is that in my use of the ICBM (in exactly that configuration) I have not found the bass to be lacking at all. If it causing a problem, I can't tell. (And Outlaw notes that it's unlikely that we'll hear any problems.)


So, like I mentioned above...if you can try the ICBM both ways, go for it. Then you'll know what works best.
 

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Discussion Starter #5
Quote:
Originally posted by HAN
Joe: (I run an ICBM for full time bass management between my Denon 3802 and a Carver 5 channel amp.)


Does the A-1 have a complete 5.1 set of pre-amp outs and power amp ins? If so, then you can try either setup you describe. And in the end, that is exactly what I think you should do.
Han,


It's an oddball arrangement regarding pre-amp outs and power ins.

The DSP-A1 has pre-in/outs for the 2 front speakers and

pre-in/outs for the Center. There is a jumper between these 3 sets and I am feeding the pre-out on the Front to a Stereo Parasound Amp connected to the Fronts.


Using the internal amp for the Center and Rears.


The Rear's are a Normally Closed RCA jack designed to allow connection of an external amp and the SUB is line level out.


Doesn't look like I can put the ICBM between ALL the ins/outs on the Yamaha because if I connect an RCA jack to the Rear, I would need another stereo power amp due to the NC connection.


Make sense?


Only had time today to mess with the DVD-A going to the A1's 6 analogue inputs.


This sure gets a bit complicated and after reading the A1's manual CAREFULLY I realized that what I posted earlier was not completely correct.


When using the 6 analogue inputs, it bypasses the DAC and the DSP chip (obviously) but bass management is available on the Yammy.

Front/Center/Rear can be set to small or large individually and the cut frequency is fixed at 90 Hz for each if set to small.



I am starting to think I made a mistake buying this.

I assumed from all the comments about DVD-A players not having Bass management that I would need the ICBM and that the Yamaha would not have bass management when using the Analogue inputs.


It dawned on me that I NEVER use Bass management from my DVD player (DD,DTS) since I can do it via the Yamaha. I have the Rears and Fronts at Large and the Center speaker to Small.


Here is the +/- 3db bass spec on the speakers


NHT 2.9 Front - 26 Hz

Audio Center 1 - 75 Hz

NHT 2.5i Rear - 26 Hz

Velodyne FSR-12 sub (12", active servo)- 20 Hz



I found the best sound was settting the ICBM to 40 Front,100 Center and 40 Rear. I could not tell any difference when setting Front and Rear to bypass.


Anything higher sent TOO much bass the Sub and the sound was boomy.


If you look carefully at my settings, you will see that I basically have the ICBM set the same way as my Yamaha's own Large and Small settings. The only difference is 100 Hz instead of 90 Hz for the Center.


Perhaps if I had a disk with front or rear bass below 40 Hz, I could tell the difference. I only had time to experiment with Brain Salad Surgery.


BTW, I re-calibrated all the speakers at the Large setting on the Yamaha to 70 DB with VE before I hooked up the ICBM. The DVD player was set to all Large also.


I am going to experiment some more tomorrow with other DVD-A and DTS CD's but I have a feeling I am sending this back.


Ideas? Or am I missing something here?


Oh yeah, thanks in advance for reading through this long post:)



Joe
 

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Joe: I agree that if the A-1 still has bass management available on the 5.1 analog inputs, and, that thru a bit of testing you have found the 90 Hz highpass to be as good as the ICBM's 80 or 100 Hz options...then the answer is pretty clear that you probably don't need the ICBM.


(Just curious...I had heard the same as Mr. Dressler noted. IOW, the A-1 does have bass redirection on the analog inputs. And you have noted that the manual says so too. My question is, have you ran some tests and verified it? The reason I'm asking is that there are only a handful of units out that have any bass management on the 5.1 inputs. And while I'm not saying the A-1 doesn't have it, nothing else in it's catagory or price range did/does.

Also, if it does indeed have bass management, is it 100% analog or is the signal digitized? You note that the manual says that all DACs are bypassed. But I had thought that hardly anyone offered full bass management in the analog domain. (One example, Denon, has it available in analog for 2 channel mode but not for 5.1.) So, I'm just curious about the A-1's pathway??)
 

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Discussion Starter #7
Quote:
Originally posted by HAN



(Just curious...I had heard the same as Mr. Dressler noted. IOW, the A-1 does have bass redirection on the analog inputs. And you have noted that the manual says so too. My question is, have you ran some tests and verified it?



---> Clarification: The manual doesn't say it but I can see from the 2 page schematic/block diagram in the back of the manual.

Yes. I disconnected the ICBM and went back to my normal setup. When I switch the Center speaker between Small and Large, the SUB comes alive or goes to sleep.



Also, if it does indeed have bass management, is it 100% analog or is the signal digitized? You note that the manual says that all DACs are bypassed.


-----> The DAC's are obviously bypassed for the Analogue input.

Bass management,balance,tone,Hi/low pass filters,channel boost,etc. are all done in the Analog domain.

The only AD this thing has is connected to the non-digital inputs eg. Tuner,Phono.


The DSP ASIC is on the digital side.


If I could post a picture of the schematic from the manual, you would see how this thing works but the on-line manual (for screen capture) is only 60 pages long and my printed one is 106 pages. On line manual does NOT have the schematic.

Regarding the NC connection for the Rears (no pre-in/out) and thus requiring an external Amp, it occurred to me that since I am not using the internal Front amp which does have pre-in/out that I could do this:


Rear out ---->ICBM---->Front in


and simply connect the Rear Speakers to the Front Terminal jacks.


Funny, I bought this thing 4 years ago because I got tired of having to ditch a receiver everytime I added some new piece of gear and found out that I did not have enough Coax or Toshlink inputs or whatever.

I figured it was worth spending $2400 for something that was future proof and it looks like it still is.



I am going to hook the ICBM between the Amps, try different music disks and Pro-logic modes (for TV) and see if the more versatile crossover frequencies are worth it.

Outlaw has that 30 day satisfaction guarantee so I have time to due a thorough eval.


Thanks for taking the time to write.

I'll post back what my findings are.


Joe
 

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Joe,


Separate from your ICBM use, have you ever compared running your 2.9s configured as large with all of the speakers configured as small?


I have 2.9s too, and discovered that configuring them as small and using an external powered 12" subwoofer makes a significant improvement in the low frequency extension. Part of it may be the usual problem of standing waves and interference patterns induced by having multiple low frequency sources.
 

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Discussion Starter #10
Seldon,

Thanks for the idea but..

I tried that and you can really localize the bass now.

I have never figured out why people say you can not tell where a sub is located due to the low frequency.


I listened and sure enough I heard misbalanced bass and the sound was obviously coming from front left where the Velo is.



Here is one for you folks to see if it happens to you. I am using a Panny RP91.

I did find that a lot of my problem was calibrating the sub to 70db with VE.

When I switch to a DVD-Audio disk, the Sub output volume is MUCH higher than on DD or DTS Audio. You can physically see the extra excursion of the Driver.


I can use the ICBM's LFE control to tame it.


Han,

I hooked it up the way I described above (between the pre-in/outs) and I am now more pleased with the sound presence using the ICBM than the Yammy's fixed 90Hz cut. It is subtle but better.


There is an extra bonus if you like a clean bass boost on stereo CD's also. My sub was always silent in Stereo until I hooked up the ICBM between the amps.


I have to listen to more of my DVD-A disks to be satisfied but if you play Track 8 on Alan Parson's On Air DTS CD, you can really hear the difference. It is a blast:)

Since I have had that CD for a year, I know it's nuances really well.


I only recently started buying DVD-A disks.


Thanks - more later.


Joe
 

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Joe: Glad to hear it! My ICBM was a subtle but noticeable improvement in my system too. For only $250, it's a great piece of gear!!!


Happy listening!
 

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JoeQ


You are quite right about the 6-ch input being non-digitized (I downloaded the user manual at yamaha.com). But at least it does offer analog bass management, and I'm sure the all important level trims. But there's no delay settings, so that will not cause any problems for the ICBM (at least for the 6-ch input).


As for whether the bass contributions from each channel will be nonuniform with the ICBM placed between pre-main, you can see by looking at the speaker gain trims in the A1 for each channel. If, for example, L/R are 0dB, C is +2dB, and rears are -6dB, then that is how the bass from each cannel will also be mixed in the ICBM's sub output (it assumes all inputs are at the same relative level). The bass isn't ever gone, but it could be uneven, particularly between different sources.


If you want see the true benefit of the tailored crossover pointsfor your particular speakers, vs the 90 Hz of the A1, without any of the gain trim issues to affect the final bass results, I'd suggest putting the ICBM in the DVD-A output path. Then you can alternatively switch all the ICBM filters to bypass while the A1 does the bass trick, or switch off the A1's 6-ch input bass management and turn on the ICMB filters. Could be enlightening.
 

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Discussion Starter #13
Quote:
Originally posted by Roger Dressler
JoeQ


As for whether the bass contributions from each channel will be nonuniform with the ICBM placed between pre-main, you can see by looking at the speaker gain trims in the A1 for each channel. If, for example, L/R are 0dB, C is +2dB, and rears are -6dB, then that is how the bass from each cannel will also be mixed in the ICBM's sub output (it assumes all inputs are at the same relative level). The bass isn't ever gone, but it could be uneven, particularly between different sources.

Roger,


Shoot, I never thought of that and now you are going to make me re-connect everything.

How can I argue with a guy from Dolby:)



My Center is at -2db. My rears are at -3 and -4 due to uneven distance from the prime seating position since I have a wierd shaped back wall.


What you are saying explains something I hear on VE when the ICBM is connected between the amps and I could not figure out why.

During the Montage of Images chapter, there is an Ice Skating scene that has 2 very satisfying booms from a bass drum.

It is a scene I always play after sound calibration.


That boom is really weak and dull with the ICBM between the amps and now I realize that it is because the bass drum is fed to the center channel which is set to -2db.



Also, I did notice that the bass was kinda odd (hard to describe) when I watched Tomb Raider last night. Now I think I know.


Back to the drawing board.


Thanks for all the help Roger.


Joe
 

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So close, and yet so far... :(


I agree that if your channel to channel levels are quite a few db different, the bass could sound poor, due to the reasons Mr. Dressler notes.


I'm lucky with my ICBM. Using it between my Denon receiver and my Carver amp has resulted in only needing to have the center down 1 db from all the other channels. So whatever bass problems I have are related to other causes.


Another advantage in my particular setup is that my 5 channel amp has adjustable input volume controls. So, I could set all of my levels to zero and make the final level balancing just before the signal goes to each speaker.
 

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I've re-arranged my rack and now my PCA short Stack cables are not long enough. Anyone need a set of these? E-me for a deal.
 

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I wish I had read this post a few days earlier. I too have a DSP-A1 and just recently bought a DVD-A player- the Yamaha CX1. I only have Queens "A Night at the Opera" DVD-A right now and think it sounds pretty good through the 6 channel inputs but thought it would only get better with proper bass mgmt so I ordered an ICBM. It should arrive 12/6 according to UPS website. If no improvement I will probably send it back. I am not using an external amp though I may add one at some point as I move down the path towards separates but am really in no hurry as I have a fairly small room and no real need for 6.1/7.1 processing at this point. I am using small speakers all around- Boston VR-M60's, VR-MX's, and VR-MC with a SVS 2039PC. If the ICBM goes back that will put that much closer to getting an HDTV :D
 

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Simm, FYI The Queen disc is only DTS Audio. Still not bad, but not DVD-A.


Before/if you decide to "send back" the ICBM, do yourself a favor and buy a true DVD-A disc to evaluate the ICBM. pick one of your favs, I like Steely Dan Two againist Nature for a current recording mixed in true 5.1 or Eagles Hotel California, although not a recent recording, it was remixed by the orignial producer for the 5.1 format.
 

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Rmassey: The Queen disc is DVD-A as well as DTS. It includes a DD track, stereo DVD-A, multichannel DVD-A, and DTS. I will listen with the ICBM in the system before I send it back if that is what I decide to do. I may end up keeping it but based on this thread and my experience so far I may not need it.
 

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Really ? I always thought that disc was only a DTS disc. My mistake, enjoy.


BTW, give the ICBM a good listen. It's well worth the money. I find myself using it on regular stereo CDs as well as DVD-A. The boost/control of the bass is very addicting.
 

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I got the ICBM Friday and hooked it up yesterday and "think" it does sound better than using the BM through the DSP-A1's 6 channel inputs. I have set the levels using the Radio Shack sound meter and played my one DVD-A disc, I am getting several more for Christmas but the wife is making me wait. I have the crossovers set for 80hz but tried the 60hz and 40hz settings with no apparent change in sound. I think it is a keeper....


Anything else I should do or know about setting the system up with ICBM in the chain other than connecting it and setting the crossover?
 
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