RECORDING Speck Model ASC Four Band Parametric Equalizer - From Recording.Org Reviews Speck Model ASC Four Band Parametric Equalizer By Kurt Foster Jul 21, 2003, 20:38 Recently I wrote a review of the Speck MicPre 5.0, a solid state high end mic pre, with many features, includi

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Speck Model ASC Four Band Parametric Equalizer
By Kurt Foster
Jul 21, 2003, 20:38

Recently I wrote a review of the Speck MicPre 5.0, a solid state high end mic pre, with many features, including a transformer that may be switched in and out of the output path. This review could be looked upon as an amendment to that article on the Mic Pre 5.0 and as a review of an additional part of the whole system, the Model ASC equalizer, as the two pieces really go together to make a complete system that is intrinsically intertwined and almost impossible to evaluate as separates. As I have had the Mic Pre 5.0 around a little while longer, I have learned some new tricks it can do and I have come to appreciate it even more! In a recent mic pre amp comparison, Recording.Org members voted the Speck 5.0 as the best sounding mic pre among considerable competition!

The Speck Model ASC 4 band parametric equalizer is a companion piece to the Speck MicPre 5.0, although either the Mic Pre 5.0 or the Model ASC EQ may be used stand alone. They both shine in either application. The build of all the pieces I received was very good with fit and finish being of the best quality. The owners manual is well done, easy to read and contains all the information the user needs to install and operate the EQ.

Packaged as a hefty half rack device the Model ASC uses a 16 VAC, @1.1 amp = 17 volt amp, "power module" (wall wart!). All AC rectification, filtering and DC regulation is performed within the chassis of the Model ASC. The ASC may also be powered from the Speck MicPre 5.0 aux dc power source, via the optional ASC-DCI cable. I prefer this method as I have a personal bias against wall warts.

The front panel of the Model ASC is jammed packed with almost all the features you would expect from a good equalizer but with a few twists. There is plenty of room for short fat stubby fingers and the graphics are easy to read, even in low light.

Speck Model ASC front panel

At the far left is a gain control to adjust the input sensitivity from -12dB to +6dB. There is a center detent at unity gain (+/- 0dB). Also included in this section is the equalizer bypass switch, useful for switching in and out of the equalized mode to compare them. When in the bypass mode the active balanced input stage (and the optional transformer, if switched in) remain operational to facilitate comparing the Eq-ed signal to the UN Eq-ed one. The equalizer bypass switch is a dual colored led, which when depressed, is green and in the out position, is red.

Immediately to the right, we encounter the L (LOW) BAND section which may be switched into either peak dip curve or shelving curve. In the peak dip mode the bandwidth of the filter is relatively narrow at .25 octave (Q=4) when the low frequency sweep control is set at its lowest setting, 20Hz and widens as you progress higher to a 1.6 octaves (Q=.6) at 150 Hz. I have never seen this type of arraignment and at first, I was skeptical. However I soon became favorably impressed by this feature. The filter may be adjusted for a boost or cut, of 15 dB.

Moving on, the L/M (Low/Mid) Band, features yet another twist, a switchable frequency range between the Low or Midrange bands. In the out position the low range (40 - 800 Hz) is selected. When the switch is pressed in, the mid band (400 Hz ñ 8K Hz) is selected. A Yellow led glows when the mid band is engaged. There are two additional knobs to adjust the "q" of the filter (.25 to 2.0 octaves) and the amount of boost, plus or minus 15dB.

The M (Mid) BAND features the conventional 3 controls we are all used to, frequency sweep, boost/cut and the Q or bandwidth adjust. At itís widest the Q of the filter is 2 octaves (Q=.5) and at its narrowest, .25 octave (Q=3.8).

H (HIGH) BAND is the final group of controls. The HIGH Band, is a peak/dip mode filter only. I personally would have like to seen a switch enabling the user to put the filter into shelving mode. The saving grace of the design seems to be that when a higher frequency is selected, the curve of the peak/ dip is a pretty wide. I found this to be workable but in some situations, I could still see myself wishing it had a shelf curve. At lower frequencies, the bandwidth of the filter is relatively narrow at .5 octave (Q=1.8) when the frequency sweep control is set at its lowest setting, 4k Hz and widens as you progress higher to a 1.8 octaves (Q=.6) at 25k Hz. The filter may be adjusted for plus or minus 15 dB.

Speck Model ASC rear panel

Turning the unit over and looking at the rear panel we find XLR input and outputs and well as 1/4" trs jacks. These are wired in parallel and present exactly the same input and output paths. The 1/4" trs jacks will accept unbalanced connections as well. There is a ground lift switch on the outputs that any be used to remedy hum in cases of ground loop. (how thoughtful).. There are two square receptacles, one for the power supply connector that accepts the four pin rectangular Molex power plug of the power module (wall wart!) and the AUX DC I/O used to power another ASC or to receive power from a MicPre 5.0. These receptacles are different in size and pin layout and there is no danger of making a cross connection. Dummy proofed!

For those of you who really crave the sound of the "iron", an output transformer option is available. (Model ASC-T). To keep the transformer from interacting with the active circuitry of the ASC, on the Model ASC-T, the transformer is wired only to the XLR connector and the balanced active output is wired only to the *" TRS jack.

The MicPre 5.0 and ASC combine to create what Speck refers to as the Mix Node. Via special cables available from Speck, 2 or more MP 5.0ís may be inked via the optional MP50-LINK2 mix link cable. The ASC EQís can then be hooked up trough the insert jacks on the MP 5.0 to form a complete stereo mix system with panning, eq and individual faders on each unit.

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Running it through the pacesÖ

My first experience with the Speck Model ASC 4 band parametric equalizer was when I used them to eq some tom tracks on a live drum set recording. With two Audio Technica 4033ís, into two channels of MicPre 5.0 ës, patched through the Speck ASC EQ's on tom toms. I found the ASCs to be very complimentary to the MicPre 5.0. I was able to quickly zero in on offending mid range frequencies and effectively attenuate them. I also used the ASC to boost the lows to fatten up the toms and a little 5k boost to add to the attack and sheen. I noticed no perceptible added noise even with extreme high frequency boost implemented. My experience with all but the best EQs on drum tones has been disappointing, however I found the ASC to be very useful and just what was called for in this application.

My next experiment was with a telecaster guitar plugged directly into a Speck MicPre 5.0, through the transformer and into the Speck ASC equalizer. The Tele had a bit of a muffled tone with the EQ switched out but once again I was able to kick the EQ in and zero in on the "wolfing" mid frequencies and dial them out in a jiffy! The H (HIGH) BAND added a very nice sheen without being shrill. I like how the bandwidth changed as I increased the frequency selection point, widening as I approached the highest frequencies, but narrow at the lower ones. I swept the frequencies around the full range of its travel from 4K to 25K and heard absolutely no hint of harshness and very little noise! This high frequency section adds a sheen and quality that is very pleasing and is very quiet.

I moved on to bass through the ASC using the Speck MicPre 5.0 as a direct input. The instrument I chose was a reissue Danelectro Longhorn. Trimming the MicPre 5.0 for max input level, I intentionally played very aggressively trying unsuccessfully to drive the EQ into overload. The L (LOW) BAND section was effective for bass instrument applications, adding a nice warm low punch at a setting of 50Hz. I again took notice of how the filter width narrowed at the lower frequency selections (20 Hz.) and grew wider as selection approaches 150Hz. I choose the L/M (Low/Mid) Band option in the LOW setting, for boosting at 230 Hz for increased audibility on small speakers. This is a favorite technique I use and the Speck responded to my expectations flawlessly. I feel very at home using this EQ! The Mid Band filtered out a few db of honk at 3k to smooth things out and a bit of high boost to add a bit of sparkle to the bass and I was happy as a clam. A very good tone that was simple to dial up.

On a whole mix once again the ASC shines! I was able to zero in on offending "wolf" notes in a mix and smooth them out, go to the deep lows and pull up some serious thump and add a sheen or shimmer to the top end of a mix without introducing excessive noise. The mid filters may be narrowed down to a point that surgical repairs are possible but may also be made broader to smooth the whole mid range. I would be reticent to call this a "mastering quality" equalizer but I would not be surprised to see someone use it as such in a home studio / mastering environment. In this capacity, it performs admirably.

To hear audio samples of the tests performed and the mic pre amp comparisons, please go to the web address below. www.recording.org/ubb/ultimatebb.php?ubb=get_topic;f=25;t=000583

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The ups and downs!

As a combination, The Speck MicPre5.0 and The Model ASC 4 Band Parametric Equalizer are a match made in Ö. Well, Iím not sure where they are made but they are a great pair! The pre is quiet and neutral sounding. Very clean with a lot of headroom. It features a direct input useful for guitar, bass and electronic instrument routing to your recorder. `There is a switchable transformer in the output path that adds the iron sound if you wish. And it has a real AC cord! (Yaaaaa!)

The Model ASC 4 Band Parametric Equalizer is a great companion piece to the Mic Pre 5.0 but also serves well as a stand alone EQ. I could see the ASC in racks in top studios across the world, as it is very quiet, even at extreme settings! I was able to plug directly into this system and dial up nice tones with tom toms, electric guitar and bass through the direct input. The sound is full and robust like that of a large format console but clean, transparent and uncolored. The variable filter width on the L (LOW) BAND and the H (HIGH) BAND is a twist but as I used it, I found it to make sense in its application. It is very intuitive in its implementation and this serves to make a very musical equalizer. I usually donít warm up to mic pres and eqís that are as transparent as the Speck MicPre 5.0 and The ASC 4 Band Parametric Equalizer but the flexibility of these pieces and the quality of the sound is nothing short of remarkable in this price range.

While I would prefer to see no wall warts in my world, this use of them is acceptable in my book as the external (beefy 16 volt @1.1 amp = 17 volt amp), power supply is used in the lower current hungry application of the equalizer and not in the MicPre 5.0. There is also the capability to power the ASC from the MicPre 5.0 in which case you can throw the wall wart in the junk drawer. Carefully though, it is pretty heavy.

I also would have like to seen a shelving filter incorporated into the high frequency section, although I must admit in use, I didnít find myself wishing for it as much as I would have suspected. It seems the designer, Vince Poulos, at Speck thought this out and came up with a very elegant solution. The long and short of it? I would be very happy to have a few of these things in my rack. Just a few more shopping days until my birthday! If you are looking for a few channels of good clean flexible great sounding front end for your recording system The Speck MicPre 5.0 and the Speck MODEL ASC Parametric Equalizer are just what the Doctor ordered!

Kurt Foster

Kurt Foster has been involved in music and recording for over 35 years. He owned and operated KFRS, a 2000 sq. ft. commercial analog and digital recording facility in the San Francisco Bay Area beginning in late 1980ís through the 1990ís, recording and working with greats such as Brownie McGhee, cult following guitarist, Kenny "Blue" Ray, Jackie Payne (Johnny Otis Band), Nick Turner (of Hawkwind) Polo Jones (of Michael Jackson, Peter Gabriel, Whitney Houston) and individual members of The Doobie Brothers, Tower of Power, Huey Lewis and The News and The Tubes. He is retired to his ranch in Cedar Flat, Oregon but continues to be active in recording, artist development, procuring recording contracts for new talent, music publishing, writing both music and music related articles as well as serving as a Moderator and Review Editor for a popular online recording forum, Recording.Org.