[dm]

EighthNerve Response Review

I recently purchased a set of Response series treatments.  I purchased 4 corners + 8 seams.  I sent a drawing and room pictures to Nathan for analysis and suggestions.  Nathan made several recommendations for placement.  I have a L shaped finished basement that is used as a hometheater.  A portion of the room over the seating area has a lowered ceiling where HVAC ducs are routed.

Here is some of the equipment that makes up my HT:
Panasonic XR45 Digital receiver
4 Mirage OMNI 50 speakers
1 Mirage OMNISAT V2 CC (center)
HSU TN1220 subwoofer
Behringer BFD EQ (for sub use only)
HTPC (DVD, CD, MP3, WMA, DIVX, etc, etc media player)
6 x DIY Ethen Winer wood panel Bass traps (http://www.ethanwiner.com/basstrap.html)
4 x DIY first reflection point HF absorber panels made from Auralex acoustic foam panels.

You can see a room layout with the linked figure.  8th Nerve products shown in light blue.

http://img101.imageshack.us/my.php?image=roomlayout5vm.gif

A quick caveat.  Nathan recommended placement for all of the response treatments.  I was unable to place the two seams on the front left and right vertical corners of the room as he had suggested.  I also elected not to purchase and place any treatments in the vertical corners of the rear of the room.  I have my DIY bass traps which occupy those areas.  All response treatments were placed along ceiling seams/corners instead.

Caveat number 2.  Unfortunately, my measurement mic moved slightly (1-2 inches possibly) between the before and after measurements.  I know that this can make a difference in the resulting measurements.  But since I went to the trouble of making these measurements while placing my treatments, I figured I would give my impressions of the session here anyway.  I also made my measurements with my speakers in a 2.1 (left, right, sub) configuration, sub cross over at 100hz.

Subjective Listening Comments:
I am going to focus on more measurement oriented comments below.  But some quick thoughts on subjective listening after the response panels were installed:

Little to no impact on bass response of my system.  (sorry Nathan)  However, in the mids and highs, things are significantly “better”.  Better meaning a much more live feeling to the music.  My small room sounds much more like an open airy uncolored large venue.  (Note that I am using Mirage omnipolar speakers which are known for live sounding).  

The single biggest impact was from the Response treatment installed across the ceiling seam just behind my center speaker which hangs from the ceiling 18 inches out from the front wall.  The one placement of that one treatment TRANSFORMED the sound of my center speaker in the critical dialog frequencies.  Unfortunately I did not measure the before of my center speaker.  All my measurements were done in a 2.1 speaker mode.  So this comment is best on subjective listening only.

Measured Comments:
I am user of RoomEQ Wizard and have tried ETF software.  I have an Behringer ECM8000 mic and mixer hooked up to my laptop for measurements.  I have extensive experience in using the software for setting my BFD to EQ my subwoofer.

Impulse Response:
The before and after Impulse response figures are fairly striking.  In the .5 to 1ms area, the 8th nerve product has reduced the peaks by 25%.  I am not sure that I can really explain this (unless it is due to the measurement mic movement).  Since .5 to 1ms translates to about 6-13 inches.  There are no Response treatments in this area that I would think would be involved.  Further out on the graph the impulse response has become more flatline (the ideal) by about 10%.  Impulse response (among other things) measures the resonances or “smearing” effects of the room.  So flatter can mean a more “transparent” sound in the room.

Frequency Response:
In the mids and highs there have been improvements.  I had a nasty peak in my 600-900hz area and a valley 1300-2700hz (measured at my sweet spot listening area).  With the 8th nerve product my frequency response in those critical listening freqs flattened out by 3 db.  (I still have some peaks and valleys there, they are just now 3db less).  The slope of the line above 11Khz has also changed.  With some increases in response in the higher frequencies with the 8th nerve products installed.  However my measurement (and ears) are less accurate at those frequencies.

RT60:
Measured about the same before and after.  With the exception of worse readings in the area 200-300hz.  However, below 200-300hz, RT60 measurements are not all that valid with my test setup.

Loudspeaker Phase:
I am not sure if I have a problem with my “before” measurements or test setup here or not.  Because after the 8th nerve products were installed these measurements improved dramatically.   Also, given I am using Mirage omnipolar (360 degree radiating) speakers, this is potentially a hard measurement to make.  Anyway, the “after” measurements show significant improvement in reducing the phase response differences between the test and measured signal.  Between 2Khz – 17Khz, a reduction in phase error of 20-80 degrees (this measurement varies widely by frequency)  Even if one ignores the “before” measurement, the “after” with the 8th nerve product tracks with very low phase error.

All in all the 8th Nerve product has improved my subjective, and caveat's aside, measured performance of my system.

A happy customer.

EDIT:  I misread my graph labels.  Impulse levels were in % not dB.  Phase was in degrees not dB.  Text above edited.

[8thnerve]

dm,

Thanks for your thorough review.  I would not expect to find that your bass improved as the vertical Seams are mostly responsible for any improvement at those frequencies.  With the Adapt line, you would see bass improvements without vertical placement, but not nearly as much as with vertical placement.

The Response line continues to offer great performance at a budget price.

Best Regards,

Nathan Loyer
Eighth Nerve

[dm]

note response treatment located in the seam directly behind the center speaker hanging from the ceiling.  Also note DIY wood panel bass trap in left corner near HSU Tn1220 sub.

http://img148.imageshack.us/my.php?image=img33226gg.jpg

[dm]

To those following this thread.  I mentioned that in the measurements in the original post, my mic had moved between runs.  I was never really happy with that fact and any potential effects on my results.  I have completely reran my ETF ( http://www.etfacoustic.com/ ) measurement runs.  

I struggled with the idea of deleting my original post since the results are now somewhat different.  But I elected to leave the original post intack and show the updated graphs below.

So here goes again with updated measurements.  For these measurements, I tested the room WITH the 8th Nerve products in place and then removed the treatments and measured again.

The BLACK lines in the graph are WITH 8th Nerve products in place.
The BLUE lines are WITHOUT 8th Nerve products in place.

When you click on the imageshack links, you will see the graphs.  If you click again on the image once it pops up, you will see it 100% zoomed at it will be clearer.

For both the black and blue runs, my DIY bass traps and 1st reflection point absorvers are in place.

Impulse Response:
Not nearly as dramatic an improvement as originally thought.  But still there.  If you look closely at the impulse graph, you can see that the peaks have been tamed slightly.  Especially out in the beyond 4ms area.

http://img143.imageshack.us/my.php?image=im5fc.jpg

ETC Measurements:
Generally measuring the decay of the echos or reverb of the original sound in your room.  You want the later reflections of the sound to be somewhat reduced.  In the graph below, given the limitations of my test equipment and the fact that my HT is in my basement with some HVAC background noise, I am not sure how valid the measurements beyond 28ms are.  So if you look at the first 30ms, you again see that the 8th Nerve products are in fact slighlty taming the peaks and reducing the echo's in the room.  

http://img95.imageshack.us/my.php?image=etc6gs.gif

Frequency Response:
Again not nearly as a dramatic improvement as I originally thought.  But there still is improvement.  These are 1/3 octave smoothed by ETF software.  One important comment.  I have Mirage OMNIPOLAR speakers.  These speakers radiate sound in 360 degrees.  Slightly weighted to forward, but a large percentage of reflected sound.  Reviews of these speakers and others who have measured them show a similar FR graph as below.  The dip and high frequency fall off is normal.  It is really hard to measure these speakers in a traditional way.  If you measure these speakers off axis response the high frequencies exhibit a similar, but NOT worse high frequency fall off.  In other words, the off axis and on axis high frequency results are very similar and the overall sound you hear is the SUM of the on and off axis response, yeilding a balanced tone overall.  (ref http://www.audioholics.com/productreviews/loudspeakers/Omnistatv2FSLoudspeakersp5.php )

Graph below is only measurming the 200hz-20khz region.  Results 0-200hz not graphed.

http://img206.imageshack.us/my.php?image=fr6kf.jpg

All in all I am still happy with how the 8th Nerve products have improved my HT sound.  The measurements are not nearly as dramatic as I originally posted.  But I thought it worthwhile to leave the original post in this thread and just update the results here.