I finally got caught up on reading the posts in this thread! (Edit: I wrote that about four hours ago.) I left work Thursday afternoon and arrived back home Sunday afternoon at 3 pm. With all the loading and unloading I spent almost 4 complete days for the GTG!
David did a wonderful job as the host. I thoroughly enjoyed my time at his house and had some wonderful food while there. His basement was perfect for this sort of GTG since it had plenty of room for attendees, it had side rooms for storage of speakers and gear, and it had walk-out access for easy transportation of gear using a dolly. David was very poised, patient, and flexible as we faced several issues (mostly Thursday and Friday).Measuring Gear
For each system that was getting some EQ we measured with a microphone. I have an iSEMcon EMM-7101-CHTB microphone with custom calibration down to 5 Hz. It is -.25 dB at 5 Hz and I was told by iSEMcon that because of its constant current power (CCP) it really is flat to DC. Even thought the mic is so flat, I still loaded its calibration into the software. I also did a loopback measurement of the Steinberg UR824 and loaded it into the software, too. The UR824 is flat down to 3 Hz on the outputs and is -3 dB at 10 Hz and -7.8 dB at 5 Hz on the mic input. We used 3 other DACs for playback during the event and they are all flat at least to 3 Hz. Digital Amp Company Cherry Plus monoblocks were used for playback. These amps are flat from 1 Hz-60 kHz. So, we had no signal chain rolloff whatsoever for playback, but had to compensate during measuring for the mic input.Measuring Software
Most of the measuring was done with Audiolense. With the first system measured (SVS Ultra) I verified measurements with both Room Equalization Wizard and Omnimic. REW was also used after EQ to verify the effect of EQ. Audiolense is very powerful software that can be used for partial correction, full correction, active crossovers, and true time delay correction. I used Audiolense to create filters for the Seaton Catalyst 12C, the SVS Ultra, and the JTR Speakers Noesis 212HT. I used partial correction with any EQ only happening below 200 Hz. With both S2 subs, the bass was actually quite smooth and not much EQ was need. Audiolense creates filters for each sample rate required for playback. One filter is then loaded into JRiver Media Center and it will automatically switch filters based on sample rate. You can also have different filters based on whether the input is 2.0, 5.1, or 7.1 and it will automatically switch between these, too.Playback Software
I used JRiver Media Center for playback. Both David and I use this on a regular basis for the playback of music and I also use it for all other media (Blu-ray, DVD, picture, etc.). It addition to the convolution engine that can playback Audiolense (or other convolution software) filters, it also has a full parametric equalizer and advanced DSP. The Bamberg Series 5 speakers have a separate lower and upper section. I setup a 4.0 output in JRiver with a 12 dB/octave 200 Hz high pass filter for the upper section. I copied the left and right to the 3rd and 4th channels and sent these to the subwoofer. The copying was done before the highpass so the subs got the full signal. The subs have a built in low pass to match the mains. This type of setup would be difficult with other software. If you can't do this kind of setup, you could run the signal to the sub section, then to the amp, and then back to the speakers. However, Phil Bamberg said he preferred the first method.
JRiver allows one to setup multiple zones. A zone was created on Friday for each speaker setup. Each zone contained all the necessary routing, level, and EQ information for that speaker setup. On Saturday we switched to the proper zone, doubled checked the levels again with an SPL meter, and then started playback of the playlist.
For the blind testing on Saturday I created another zone for each speaker/sub combination. For example, speaker C used output 2 for the Catalyst 12C and output 8 for the dual S2 subs. Speaker E used output 6 for the Noesis 212HT and output 8 for the dual S2 subs. As you can see, a both zones used output 8 for the sub. I had measured and created filters for all the speakers using Audiolense. However, due to the way I had to measure each speaker separately and the way the routing was setup in JRiver I couldn't get the filter affect playback of the correct channels. This caused some delays at the beginning of the GTG so finally we just played each speaker without the subs and no EQ. It was disappointing. I could have quickly created crossovers in JRiver and still used the subs, but it would have required level matching again and we felt there wasn't time.
For the movie playback later in the evening, JRiver was also used for some of the playback. I setup crossovers at 80 Hz and distance setting for each speaker in its Room Correction DSP. The levels were also adjusted for the rears since they need about 6 dB more volume to match the mains. Since I had 8 channels of output, the subwoofer could have been copied to another channel, but we just daisy chained the subs since they have that capability and both were positioned symmetrically.Four Way speakers using six different speakers and two subs!
I wanted demonstrate the active crossover feature and capabilities of Audiolense. At the end of the blind listening I played back music through 6 speakers and two subwoofers for a 4-way system. I only spent 10 minute to set it up, take a measurement, create a filter in Audiolense, and load the filter in JRiver. Audiolense set the proper levels, delays down to the 100th millisecond, EQ for a smooth frequency response, and made sure all drivers were in phase. When standing in the measurement spot, it actually sounded quite good, but if you moved around the room the timing would be all messed up. It was a fun little exercise. Below I show the setup in Audiolense:
Bass - S2 sub (80Hz and down)
Lower Midrange - Seaton Catalyst (80-600 Hz)
Upper Midrange - Bamberg Series 5 (600-4000 Hz)
Tweeter - LS6 (4000 hz and up)
Bass - S2 sub (80Hz and down)
Lower Midrange - Seaton Catalyst (80-600 Hz)
Upper Midrange - Bamberg Series 5 (600-4000 Hz)
Tweeter - LS6 (4000 hz and up)
Here you can see what the "speakers" looked like. We had the tweeters to the outside with the lower midrange in the middle:Level Matching
Bob Katz, author of Mastering Audio: The Art and Science
, recently helped JRiver implement an audio calibration system that met the standards of SMPTE RP 200. This is the standard used by the studios for calibrating their equipment prior to mastering movies. From the JRiver wiki:
"If you use Internal Volume, you may want to calibrate the volume control so that the zero point matches the "reference level."
The audio industry does not have a standard for playback system calibration, but in the movie industry a calibration standard has been defined by the Society of Motion Picture and Television Engineers (SMPTE). The standard states that a single channel pink noise signal with an RMS level of -20 dB relative to a full-scale sinusoid should be reproduced at 83 dB SPL."
This audio calibration system in JRiver was used in conjunction with a Galaxy CM-130 SPL meter. Limited range pink noise was used on the left channel and the volume level adjusted until it reached 83 dB. This ranged from about 50% to 93% of the volume. The percent number was entered in JRiver's Audio setup and would correspond to 0 dB on the volume. The subs were set at a similar level for the SVS and Seaton systems. Jeff ran the subs hotter for the Noesis system.
By the way, 83 dB isn't designed to be a listening level, but a calibration level. Bob Katz said, "83-85dB is too loud for me anyway. I don't ever listen to my hifi anywhere near that loud even when just enjoying my favorite songs, never mind for hours at a time."
For the blind listening each zone was set properly and then adjusted to -15 dB fro playback. This way all speakers would be level matched. We also played each system later at -15 dB except for the Noesis. After the playback on the first system (Bamberg), no adjustments of any kind were made until the final system (Noesis). Jeff had his bass hot and the listeners decided they wanted the mains a little louder, too. We increased the volume to -10 dB during most of the the Noesis formal playlist.
After the formal playlist, individuals and manufacturers could pick music and then ask for an increase/decrease in volume level. This was a fun way to either listen comfortably or explore the limits.Speakers
I've always heard that speakers/equipment sound better at RMAF on the second day after more tweaking had been done. After hearing all the systems on Friday and then again on Saturday I think I understand a little better why that is. I thought everything sounded better on Friday than on Saturday. Adding people to the room changes things and made it sound a little worse on Saturday. It would have been interesting to do a measurement with no people and a measurement with people in the room. My comments below might include some setup details or things I noticed from Friday instead of Saturday.
- Bamberg Series 5 - I really liked these speakers. Once music starts playing, the speakers completely disappear more than any of the others. For my normal listening levels they had a great imaging, wide sweet spot, and smooth sound. As I mentioned above, these have a 200 Hz high pass on the top section with the sub bass handling below 200 hz. The bass very good.
- SVS Ultra - When I was doing the blind listening setup, the SVS always sounded the most different from the other speakers. The finish was beautiful for speakers of their price. On Friday I thought the bass sounded flabby, but it seemed okay on Saturday when we used them fullrange. Pulled out into the room they don't get near the low frequency listed on their specs.
- Seaton Catalyst 12C - Power wise, this is one of the first times the 12C has been in a more level playing field. The amps used to power the other speakers measured over 400 watts at 8 ohms and right around 800 watts at 4 ohms. I think this helped bridge the gap in dynamics between the Catalyst and other speakers. The speakers are very clear, dynamic, and enjoyable. You can definitively notice the instant, sharp peaks on notes with high output. The speakers were very easy to setup since they already have amps. The bass was amazing even with the subs when we played them fullrange.
- GR-Research LS6 - I own these and love them. Due to their size I wouldn't have just gone out and bought them, but I was able to buy the cabinets cheap at the av123 auction and then build them out. I decided to run them fullrange with no EQ (like the Salks). The bass is too hot on these without EQ and from 100 Hz and down can go up by 10 dB. I usually listen to them at home with EQ and a 40 Hz crossover to my infinite baffle system. So far I haven't been able to get a very wide sweet spot with them. I'm going to try a few things others were doing and see if I can get it better. I noticed during the formal playlist that the sound really pulled to one side or the other depending on seating location. I thought the very middle was the only place there was a good soundstage. I did have some fun with the bass and turned up the volume when I replayed a portion of Poem of Chinese Drums. The power these have during that song always amazes me. During the playback on Saturday, I thought these were the most dynamic. I also thought that some songs sounded the worst on these speakers and the Bambergs. Maybe these speakers were the most revealing.
- Salk Veracity HT2-TL - This is the second time I've heard these speakers. If I was to purchase one of these six speakers for my living room, these are what I would buy. They have the sound quality I like in the asthetic quality, size and budget that could work for me. We played them fullrange on Saturday with no EQ at David's request, but used with them on Friday with the dual S2 subs and a little EQ. Both ways they sound terrific and fullrange they have more bass than seems possible. I really like the sound of the tweeter
- JTR Noesis 212HT - I've measured these in my room at home and in David's room. In both they show an incredible immunity to room effects. At the mic position, the speakers were almost ruler flat. When measured with the subs it was flat from 5 Hz up to 20 kHz (before Jeff turned up the subs!). The Catalysts were a very close second in measuring the flattest in-room. After the Bamberg's, I think these did the best job of disappearing. It was just pure, clear, beautiful sound coming from the front of the room. These have an extreme sense of clarity to them. Several people PM'd since last fall when I had these and the LS6's in my room. I said to all of them that the Noesis have greater clarity that the LS6's. As I mentioned in my previous review, "the Noesis is a "no regrets" type of speaker that will be exceptional at most things and excel at just about everything."
Late at night, once all the two channel guys had left
, we setup a JTR Speakers 5.1 system comprised of 3 Noesis 212HT speakers for L, C, R; 2 Noesis 228 HT for surrounds, and 2 Captivator S2 subwoofers. I used my HTPC for playback, an 8 channel DAC with balanced outputs, and three monoblock and one stereo amp from Digital Amp company. All together we had 12,000 watts of power available! By using an HTPC as the source, you never have to worry about clipping the digital signal. Nothing else can add any gain or cause any issues between the source and the amps except the DAC. The DAC I used has variable gain trims so you can set the output gain to never overdrive the input on your amp. You can also use amps with different sensitivity for the various channels and level match with the DAC. I had them set to +4 dBu and level matched in JRiver because this was just a temporary setup. We calibrated with JRiver's audio calibration and once reference level at 83 dB was set, we still had 18.5 dB of gain available! Because the 83 dB SPL in the room is set with an RMS level of -20 dB, we could play each speaker at 123 dB! Furthermore, Jeff had the subs set 7 dB hotter than the other channels.
I think the loudest I went was +15 so we still had even more headroom available. Most stuff was played at 0 or +5 above reference and it was still extremely loud.
I've heard dual Orbit Shifters played extremely loud at Archaea's house, but this is the loudest I've ever heard an entire system. You could just keep turning it up with no compressed dynamic from lack of power or exceeding driver capabilities. As mentioned earlier, Jeff finally had to cover his ears. I think Jeff or Mark checked to see if the clip light was on on the subs and I don't think it was. I can't imagine anyone ever needing more than two of the S2 subs. This 5.1 system showed how immersed you can get in the sound without needing 7, 9, or 11 channels. To me, quality beats quantity every time.
This was a great GTG and I enjoyed meeting everyone. I felt the pacing was relaxed and I really enjoyed the various presentations and the song game. Besides Carp, there were several others than knew most of the songs. Carp was just quicker on the draw. I think the GTG appealed to a wide audience. Even though we use EQ and subs, David and I ran our speakers with no EQ or subs. We also had speakers fullrange with EQ, built in subs with one PEQ on each sub, and speaker/sub combos with the subs EQ'd. Hopefully guys had a chance to compare the pros/cons of using subs vs going fullrange and enjoy sampling speakers with such different implementations.
The last summer's Iowa Crawl that started at David's was the hors d'oeuvre, the January GTG was the soup, this one was the salad. Now that he has the process down, the next one will be THE MEAT!Edited by desertdome - 5/1/13 at 6:42am