Another new direct-sales product, this one from Hagerman Technology a direct company located in Hawaii that specializes in tube based phono pre-amps, pre-amps and amps (they make several other items as well). Most of their products are available complete or as ‘half-kits’ which consist of a PCB board and instructions with a parts list. The parts are then ordered from popular online electronics supply shops like DigiKey. Jim Hagerman’s most recent creation is the Chime DAC, a combination of a DAC daughter card (aka HagDAC) and a motherboard that contains the input selection and a tube output stage.

The HagDAC is a PCM1704 based 8x oversampling 24-bit DAC that is pre-assembled using surface-mount components and can be purchased separately for $499 for use in other applications.

The motherboard has two S/PDIF and one USB inputs allowing it to operate as a traditional DAC or directly connected to a PC. A completed Chime costs $1,799 while the components to build one yourself cost just under $1,000.

I have built one of Hagerman Tech’s least expensive half-kits, the Bugle and have been very happy with it in my occassional vinyl use. I am considering the Clarinet tube pre-amp as a future DIY project.

Jim provides support for his customers both directly and via the Hagerman Tech Circle on AudioCircle.

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Another item I’m looking forward to seeing at the Rocky Mountain Audio Fest is the Salk Sound HT3a. The base HT3 has received great feedback by buyers on AudioCircle and the HT3a replaces the stock crossover with a DEQX PDC2.6P for active tri-amping with room correction. Of course, this all comes at a price. An HT3a with DEQX PDC2.6P, but no options (finish options can add $1,000+) or amplification will run you $7,495 (a base HT3 with standard crossover runs $3899). Add a six-channel ATI amp and you’re at $9,995.

While it’s outside of my budget, it should fit right into the range found at the RMAF. Not only am I looking forward to hearing them, but the finish work on Salk speakers is also raved about. Just check out the Veracity of the month gallery

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In order to better understand what I am hearing, or not hearing in some cases, I have started running various pieces of music through the spectrum display in Adobe Audition 1.5. This started based on discussions about what frequencies certain vocals used.

Here’s a good example that includes insturments and vocals, but isn’t too busy: Cold Cold Heart off of Norah Jones’ ‘Come Away with Me’ album. This first image shows the first ~22 seconds of the track with the lyrics overlaid along with some additional notes. The verticle scale goes from 0Hz to 22,000Hz.

As you can see, most of the energy is below 5,000Hz, so lets change the verticle axis to have a 5,500Hz max.

We can better see the bass notes are below 500Hz and the intro piano is in the 1,000Hz range (we’ll focus on those more next). We can also see vocal energy ranging from ~250Hz to above 1500Hz. Of course, in both this image and the prior one, we can see energy well above the vocal range during the vocals. I’m not sure what this is at the moment, but I’m guessing it’s an artifact of the recording or engineering process.

Here’s a close-up on the bass and piano section. Note the scale on both axes: 8 seconds and 1000Hz.

Not only do we see the primary bass notes between 50Hz and 200Hz, but we also see the harmonics of those notes at regular intervals above them. A few piano notes can also be seen in the upper part of the image.

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The Rocky Mountain Audio Fest is less than a month away now. This will be the second year of the event. I attended for a few hours last year and only saw a portion of the show. There were dozens of rooms setup for listening by manufacturers and retailers. Most of the systems were high-end two channel setups, although there were a couple of multichannel setups. Systems included both digital and analog sources (including a couple of reel-to-reel setups) and ranged in cost from ~$1,500 to ~$150,000. For an excellent collection of pictures of last year’s event, see AudioGon’s gallery by company.

For information about this year’s show, visit the RMAF website.

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I’ll start the ball rolling on product updates from direct-sales audio companies with the new RA8 from RAW Acoustics and GR Research. I’m looking forward to hearing this one at the RMAF in a month since Danny Ritchie seems pretty excited with it.

It’s an array using the GR Research M-130 woofers and a ribbon tweeter, but the middle two woofers are in a separate enclosure D’Appolito style. $2k completed, $800 for a kit (intro price).

Here’s the thread in the GR Research circle and the thread in the RAW Acoustics circle. The official product page.

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Below are some measurements I made in my home theater using my ETF/ECM8000/MobilePre setup. Each time I do a set of measurements I first do a new baseline set (what is shown below) before making changes and measuring the impact of the changes. I also measure at least the six marked positions along the main sofa for the baseline and each change. This takes a little bit of time, but isn’t too bad and provides a lot more information than measuring at a single point only.

The first measurement shows the frequency response at each of the six points along the main sofa starting toward the center of the room and working toward the wall (see www.bradjudy.com/audioblog/2005/08/07/the-room/ for the room diagram).

As you can see, the response holds mostly steady at some frequencies as the measurements move and I suspect this is because the measurements are in a straight line parallel to one set of walls. However, at other frequencies, the response changes significantly along the sofa. The extreme of this change is highlighted in the graph with exact values on the right-hand side.

This is a waterfall graph for one of the middle (sub3) positions fromt he same set of measurements:

And here is a time slice view of the same sub3 measurement. The author of ETF suggests using the time slice graph method over the waterfall for displaying information on decay.

As you can see from these two graphs, there is a significant ‘ringing’ of a room mode around 23.5Hz as well as a smaller one around 32Hz. Fortunately, most of the 10-100Hz frequency range doesn’t exhibit much ringing.

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Subwoofer phase is a pretty simple concept in speaker/sub integration, but it is often overlooked by people starting out. Typically a subwoofer has either a phase switch (often labeled with either 0/180 or normal/reverse settings) or a phase knob (which allows more granular control of the phase).

This is sometimes misunderstood because the idea of a crossover point is viewed as a ‘brickwall’ or an immediate hand-off from the speakers to the subwoofer at that frequency. In reality, there is a fairly wide range where the speakers and sub overlap.

The basic concept is for the speakers and subwoofer(s) to be working together in this overlap area instead of fighting each other (constructive versus destructive interference to use physics terms). This is accomplished by adjusting the phase (and possibly position) of the subwoofer to get it in sync with the main speakers (in a purely home theater setup, an argument can be made that coordination with the center speaker is more important).

Below are two graphs showing the frequency response in my home theater with my Hsu VTF-2 sub and Ascend Acoustics CBM-170 mains using the 0 degree and 180 degree phase settings. In this example, the 180 degree setting results in a pretty flat response (close to +/-2db from 20Hz to 130Hz), but the 0 degree setting has a very large drop (greater than 15db) in the crossover range.

180 degree phase setting (click to enlarge):

0 degree phase setting (click to enlarge):

Measurements using standard setup at position 3 in room diagram.

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I’m finally getting around to putting down some more notes on the AV123 get together earlier this month. Here is a summary of the equipment present and some comments:

Theater room:

Mains: Rocket RS1000
Center: Rocket RSC200
Surrounds: Rocket RS850
Rears: Rocket RS550
Subs: 2x Rocket UFW-12
Pre/pro: Emotiva LMC-1
Amp: Emotiva LPA-1
Sources: Denon 2910 and Onix CD-2 w and w/o Perpetual Technologies P-1A
Etc: R-DES parametric EQ on subs, plasma display, Panamax power

I assisted Dave Tremblay, the inventor of R-DES, with measurement during the sub EQ process using the setup listed earlier here.

Multichannel audio room:

Mains: Onix Reference 3
Center: Onix Reference 100
Surrounds: Onix Reference 1.5
Sub: Rocket UFW-12
Pre/pro: Emotiva DCM-1
Amp: Emotiva MPS-1
Source: Denon 2910
Etc: R-DES parametric EQ, Panamax power

Smaller theater room:

Mains: ELT LRS with PBS powered woofer stands
Center: ELT center SE
Rears: ELT DPA dipoles
Sub: ELT SW-10SE
Receiver/source: Pioneer combo
Etc: 30″ LCD TV

Two channel room:

Mains: Rocket RS760 and XLS (Onix Reference 1.5 for a period of time)
Integrated amp: Onix/Melody SP3 and Onix X-empower beta unit
Source: Onix XCD-88 and Onix XCD-99

This room got a LOT of attention because both speakers are new, the SP3 is a popular item at the moment, the X-empower is new, the XCD-99 is new, and the designer of both the RS760 and XLS (Danny Ritchie from GR Research) was in the room discussing the speakers.

Static display:

Rocket RS850 in piano gloss rosewood finish
Strata Mini speakers
Onix Reference 1 and Onix/Melody SP3
Rocket UFW-10
Onix CD-2
Emotiva DMC-1 based receiver (using D2Audio amp module)
Emotiva BPA-1 two-channel, bridgable amp
Audio Protien rack

One of the focuses of the GTG, SOCS and MMK for the Perpetual Technologies P1-A, was not really on display, but there were multiple sessions to demonstrate the measurement technique, discuss the SOCS corrections, and demonstrate the difference SOCS makes in playback.

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Acoustisoft (aka Doug Plumb), makers of ETF, have released R+D (Resonance & Distortion) 1.0. It’s similar to ETF, but designed to do averaging of multiple curves for working with room problems. It also does DSP/EQ modeling of the Behringer DSP1124 Feedback Destroyer (BFD) in a way that is supposed to be much more accurate that typical EQ result modeling. The advanced version also has features to automatically pick EQ points for a give measurement or average of measurements. Here is an AVS thread on R+D

I have gone through Doug’s videos and started poking around with the application. I will post more when I have a chance to try it and compare to ETF. Doug says it will eventually have all of the capability of ETF and could be considered ETF v6.

It’s an interesting deveopment of the product geared toward addressing room issues via EQ, which is a popular topic at the moment. Given the low cost of a the BFD ($100) and the relatively low cost of the software compared to some options, it seems like a useful tool for many people.

Of course, Room EQ Wizard is still free and overlaps in function, but lacks the important averaging of multiple measurements. Unless you listen alone in one place, this is very important.

Since the BFD isn’t designed with home entertainment use in mind, it does lack some function of its more expensive counterparts (Onix R-DES $400 and Velodyne SMS-1 was $500 now $700), particularly their ability to store mulitple EQ curves and easily switch between them. On the other hand, the BFD is designed for full-range EQ and could be used on main speakers as well as subwoofers.

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I have started reading the Master Handbook of Acoustics to learn more about acoutics and room behavior. So far it seems like a pretty good resource, although the author makes some assumptions about the reader’s understanding of mathematics and ability to pick up on things quickly. To pick up on some of the topics hands-on, having a copy of ETF (the author uses ETF in examples, so having this particular program is useful, but other software could accomplish the same thing) and appropriate hardware to to basic measurements is helpful.

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