System downsizing experiment

Mon40CSMM10

I decided to change my system around so I could turn things up a bit more without having too much overpowering bass in my living room area.

* Polk Audio Monitor 40's: removed and put into storage, replaced with Polk Audio M10 speakers, set to Small in the AV receiver.
* Polk Audio CSM: no change to the center channel speaker, left at Small.
* Polk Audio M10's: moved to the fronts, surrounds replaced with KLH TW-09B speakers, left at Small.
* Polk Audio PSW110: no change to the subwoofer, left at Yes (not Plus, since fronts are set to Small the Plus option is not available).

The AV receiver crossover was set to 80 Hz. Calibrated them all to 75 dBC peak using a Scosche SPL1000 sound meter, except for the subwoofer. PSW110 subwoofer was manually dialed in to the desired amount of bass.

More follows below, but in summary, the smaller front speaker configuration works well for my apartment's living room size. (Room size measurements are approximately 16 feet wide by 10 feet deep by 7.5 feet high.) The Monitor 40's just had too much output per volume level around the AV receiver's volume settings of -63 dB to -50 dB. (AV receiver range -94 dB to -8 dB, don't know why they don't go all the way to 0 dB on that receiver.)

I square bracketed the rest of the post because it's just explanation and opinion, for the most part.

[Result:
A slight loss of misbass punch due to replacing the Monitor 40's with the M10's. Also, I noticed gain in midrange clarity due to only one woofer in the M10's vs. the Monitor 40 speakers having two woofers. It also might be that the M10's are front ported while the Monitor 40's are rear ported and therefore the Monitor 40's bounce bass frequencies off the wall. The PSW110 subwoofer amp dial was slightly increased from the 8 o'clock analog clock hour hand position to the 8:30 position. I wanted the bass to be audible, including bass instruments, but not overpowering. Obviously, the bass is louder in the corners of the room than towards the middle of the room.

Verdict:
I think the Monitor 40's actually work best as fronts and without a subwoofer, if they are set to Large in the AV receiver. I tested that, and although it was still a bit overpowering in the living room, it wasn't as thick of a midbass response with the subwoofer not also outputting bass for music. I know that -3 dB bass response for the Monitor 40's is 47 Hz or so, but I've measured audible bass down to 40 Hz--using "The Ultimate Test CD" (MWCD 1112)--and there is even a bass response down to 30 Hz though it is mainly heard as speaker cabinet resonanance.

To my ears, the full potential of the Monitor 40's is just not realized when set to Small, even with the AV receiver crossover set to 50 Hz instead of 80 Hz. The lowest bass frequencies are attenuated so the woofers effectively become midbass drivers. I suggest that Polk Audio recommend a Large setting for the Monitor 40's (Monitor 40 II's, TSi 2000's), so that the subwoofer can be used for movie LFE tracks but the Monitor 40's give their full capability. Otherwise, combining Monitor 40's plus PSW110--in my room configuration--makes the midbass too heavy and too unnaturally punchy. It's almost as present as car audio, at volumes above -60 dB and higher for music, either from the radio or from CD or MP3. Then I have to turn the volume down, which makes music, movie, and TV vocals start to become too low. The other way to compensate for that is the subwoofer needs to be turned down but then it is too low for movie LFE tracks in action scenes.

If I move to a larger home in the future, I will revert back to Monitor 40 speakers for the fronts and M10 speakers for the surrounds. I'll probably run the Monitor 40's as Large and the PSW110 will be for the movie LFE tracks. Why? Well I did an experiment with the Monitor 40's set to Large and only running two channel, it sounded great with the bass and treble tone controls left on flat. Using Dolby Pro Logic II Music mode added some center channel presence with minimal surround presence with a Center channel depath of +5 (range 0 to 7) and Dimension of +1 (range -3 to +3). Those Monitor 40 speakers are way too good for the discounted price I paid for them years ago at a Circuit City that was going to go out of business soon ($96 for the pair!), and I have no plans to get rid of them, but they are also just too much output for the room configuration in my apartment. I think if the room were deeper, I could put them further away from the wall than the minimum recommended 6 inches away.

I also switched the two channel configuration in the other room to Sony SS-B1000's which, interesting enough, measure all the way down to 60 Hz even though the manufacturer gives the lower end of the frequency response at 80 Hz. I used the same Ultimate Test CD's test tones to test the Sony speakers as I did all the Polk speakers.]

Well, that's my system experiment. Comments are welcome.

tonyb

Couple things....if your sub is as you say, too boomy or not good for movies and you have to constantly adjust it, then you haven't dialed it in properly. Another thing is, the psw line isn't the best for double duty use. Hit up a Rel T series for that size of room for better results. Seems to me placement in that room is your biggest problem. Also that center channel is too small in my opinion. Try a cs20 for better voices. And....MP3'S ? Really ? Whats up with that ? You'll never get anything to sound good using mp3 as a source. Maybe low level background music, thats about it. You have lots of issues going on, but mainly, the room and placement. Couple that with some slight gear changes and I think you could rock that apartment.

Another idea is to get rid of the center channel all together and let the M40'S handle it. Set the receiver to phantom or "no" center to redirect the voices to the fronts. Some like it, some don't, but never hurts to try.

Mon40CSMM10

It was the Monitor 40's were too boomy for the room, even with a car audio style bass blocker (Scosche XOHP high pass crossover) added to them. I am able to control the subwoofer with its amplifier dial.

As for MP3's, it is more convenient to convert my CD's to MP3's (at 160 kbps) than take out the CD each time I want to play it.

Compared to the Monitor 40's, when I went to the M10's I lost some midbass punch when they were set to small. Since Polk tends to underrate their speakers, I think, I used the same test CD to test tones through the M10's. Polk says 60 Hz on the low end of specifications, but I got down to 50 Hz. Same goes for the CSM center channel, it's two of the same woofers as the M10's plus the same tweeter as the M10's.

So I ran a test, what if I set the M10's and CSM to Large, starting with Music listening on the radio? Well, I know what it does, it does no bass management so the speaker's natural roll-off determines the bass and treble limit of the speakers.

Now, home theater theory may disagree with this but in a two channel music configuration, that's how it would be: two bookshelves connected to a stereo amplifier. I don't run music in stereo, however, I run them in Pro Logic II Music mode. Pro Logic II Music mode has a center channel presence. I use a value of 5 (where 0 is center channel only and 7 is no center channel). Well, I got just the right amount of midbass presence with the fronts and center set to Large. I don't listen at reference levels--the loudest I have turned music up has been -50 dB, and the loudest I have turned a movie up is -43 dB--so I don't worry I will cause clipping and blow a speaker component. (Again, the receiver's volume level range when set to Speaker 8 Ohm is -94 dB to -8 dB.)

I left the surrounds at Small because their rolloff is 80 Hz, and the AV receiver crossover is 80 Hz. The alternative of leaving fronts and center at Small but setting the crossover to 50 Hz would have sent lower frequencies to the surrounds.

Now, when Front is set to Large, the default behavior for the AV receiver is to route only the LFE to the subwoofer. This is not acceptable for me for music listening, since the fronts and center do roll off at 50 Hz. However, Pioneer also has a Plus setting, it will also route bass from the Front channels to the subwoofer.

After calibration, and after testing the front and center set to large, it looks somewhat like this:

Quick Setup selections:
? Is Subwoofer used? Yes.
? Number of Speakers: 5.1 Channel.
? Room Size: Small.
? Listening Position: Back.

(Room size measurements are approximately 16 feet wide by 10 feet deep by 7.5 feet high.)

Speaker Settings (after using Quick Setup):
? Front: Large. (Polk Audio recommendation is Small.)
? Center: Large. (Polk Audio recommendation is Small.)
? Surround: Small.
? Subwoofer: Plus.

Speaker Distance settings, change from default values set by Quick Setup:
? Front Left: 9.5 feet (Quick Setup default value) => No Change.
? Center: 7.5 feet (Quick Setup default value) => 8.5 feet.
? Front Right: 9.0 feet (Quick Setup default value) => 9.5 feet.
? Right Surround: 6.0 feet (Quick Setup default value) => 2.5 feet.
? Left Surround: 6.0 feet (Quick Setup default value) => 2.5 feet.
? Subwoofer: 9.0 feet (Quick Setup default value) => 6.5 feet.

Channel levels--approximately 75 dBc peak channel volume level (except as noted):
? Front Left: 0.0 dB (Quick Setup default value) => -5.5 dB.
? Center: -1.5 dB (Quick Setup default value) => -3.5 dB.
? Front Right: 0.0 dB (Quick Setup default value) => -4.0 dB.
? Right Surround: -3.5 dB (Quick Setup default value) => -8.0dB.
? Left Surround: -3.5 dB (Quick Setup default value) => -6.0 dB.
? Subwoofer: 0.0 dB (Quick Setup default value) => +6.5 dB
o High subwoofer channel volume to power on subwoofer amplifier at lower volumes.
o Connected as receiver LFE/Sub Out to subwoofer R/LFE input.
o Phase switch at 0.
o Low pass dial at LFE.
o Calibrated by ear to blend in low bass with front channel and center channel bass. (Amp dial pointer near the 8:30 analog clock hour hand equivalent position.)

Crossover Setting:
? X.Over: 80 Hz.

It's enough sound to fill the room and even be heard in the adjacent rooms or outside with the patio door open. Yet, it's not too much sound that will get me a noise complaint. In order, my primary usage of the setup is music (radio, MP3's), video games is secondary, and the tertiary usage is for movies.

decal

As for MP3's, it is more convenient to convert my CD's to MP3's (at 160 kbps) than take out the CD each time I want to play it.

It's just as easy to convert them to a lossless format. You will never know the potential of your system using the mp3 format.

gmjungbluth

Thanks for writing this all out. A thoughtful experiment. Glad to hear you're happy with your results.

Mon40CSMM10

Well, it was just an experiment, but I found the limitations of it.

While the M10's worked well for music listening and video games, they didn't do so well for TV and movies. So, I went back again to the Monitor 40's. It turns out another way to control bass on the Monitor 40's is to actually put the rear port closer to the wall = less boomy bass.

The M10's ended up being computer speakers. They work well enough with the soundcard mixer volume between 20 and 30 out of 100. How I did that:

1. I cut a length of RCA cable for each speaker, one from the white connector, one from the red connector.
2. One connector at a time, first I stripped off the some insulation, revealing speaker strands and a smaller insulated wire.
3. I twisted the speaker strands together and stripped off some of the insulation of the smaller wire.
4. I twisted the strands together of the smaller insulated wire, making sure none of them touched the other twisted strands.
5. I did the same thing with the other cut length of RCA cable, steps 2 through 4.
6. With one of the lengths of RCA cable, I connected the white strands to the plus side (red 5-way binding post) of the left speaker, and the other twisted strands to the minus side (black 5-way binding post) of the left speaker.
7. With the other length of RCA cable, I connected the red strands to the plus side of right speaker, and the other twisted strands to the minus side of the right speaker.

At that point, each M10 had its own RCA connection. Then I used an RCA barrel adaptor for each speaker's RCA connector. Afterward, I connected an RCA Y-cable to the computer, connected the white RCA to the left speaker, connected the red RCA to the right speaker. Done.

(Credits to BSR for including the directions for modifying the RCA cable with their Amplified Subwoofer product.)

zingo

decal wrote: »

It's just as easy to convert them to a lossless format. You will never know the potential of your system using the mp3 format.

This is not a true enough statement!