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Tweakers' Asylum: REVIEW: Behringer Ultra-Curve Pro 8024 Other by Pat Wen

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REVIEW: Behringer Ultra-Curve Pro 8024 Other

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Model: Ultra-Curve Pro 8024
Category: Other
Suggested Retail Price: ~$500
Description: Digital 24-Bit Dual-DSP Mainframe: 31-Band Graphic EQ / Real-Time Analyzer / Parametric EQ / Feedback Destroyer / Delay / Level Meter / Limiter / Gate
Manufacturer URL: Behringer
Model Picture: View

Review by Pat Wen on June 23, 2003 at 22:43:32
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(This review was spiced up by my good friend Vincent Luk who’s a better politician than I.)

UC8024 – Sinks Boomy “Subs” Without a Trace

(geddit? German and U-571!)


The following is a hugely delayed Part II review of the Behringer Ultracurve (UC8024). Just as with many things in life, a lot of unexpected things happened over the last year and as a result, progress on the audio side suffered as a consequence. But I guess I’d better post the review before Thorsten comes out with his new DEQ24/96 review.

At the outset, Thorsten piqued mine as well as many others’ interest with his very good and detailed review on EnjoyTheMusic:


To summarize, there is just no way that I could match such a detailed and through write-up so I will not even try. However, what I thought might be useful would be to post my findings as I come from more of a layman’s perspective.

Executive summary in a FAQ format.

I. What does UC8024 do?

– it removes most of the coloration in your room. A good analogy is that before, if you were having Thai-spiced fish or Indian curry fish, you are now served Japanese sashimi (raw) fish.

If properly executed, the sonic improvement can be as much as 30%. It will solve most (if not all) your bass problems, you may now use floor stand speakers in a relatively small room without booming. It also add body and presence to your mid-range and further cleans up any congestion in the sound.

In particular, if you use a subwoofer, the benefit is towards the higher end of the improvement scale due to this piece of equipment’s unavoidable by-product of accentuating room modes.

II. How difficult to set it up?

- moderate (Digital IN/OUT) to fairly difficult (analog IN/OUT). Beware that the UC8024’s interface was surely design by Microsoft and not Apple, which means it is designed for aliens from Mars and not us mere Earthlings.

- which IN/OUT shall I use? Digital or analog?

For people with little or no pro audio experience, nor any level matching experience, ONLY the digital option is viable!

In addition, the analogue IN/OUT is NOT recommend for the layman as it is way too complicated and convoluted. For the more experienced, the analog IN/OUT should be used but only after the tweaks-replacing the stock cheapy (and I mean cheap) capacitors with better quality ones such as Sanyo OSCONS. Be prepared for some frustrations along the way.

III. Any setup tips?

- Read the manual a few times at the very least..

- Situate your speakers into the corners to excite all the room modes, the purpose is to get the max effect so that you can then equalize from that basis. By placing your speakers into the corners, it should also improve the mid and high range by better controlling the dispersions.

- Remember to add Thorsten’s suggested curves (use the “LOAD+” function), otherwise the flat EQ setting will sound too bright.

- The UC8024 will grow on you, once you get it right, you will not want to take it out of your system.

Last but not least – do send Thorsten a thank you note for (1) discovering the UC8024 for consumer use; (2) his suggested curves and (3) his details review and tweak tips.

Here is mine, ThanX Thorsten.

(Now for people with a bit of spare time)

The Sonic Impact of UC8024

My room is relatively “good”, 4.5(L) x 2.5(W) x 2.8(H) meters, however even with my bookshelf speakers, I have some very strong room modes at around 35Hz, which I can’t get rid off. The bass is always too boomy and the mid-range is recessed.

Once the UC8024 was setup correctly (no small task), and Thorsten’s EQ curves were superimposed on the flat EQ curve:

http://f3.grp.yahoofs.com/v1/oM_2PjufU6N6k4jVtutCqURpmhotwwhNLqfbaKizgk-vKNrdEZJZ7jhGdnQG9aBrWcQyLMWs4Y9IpveF/TL Circuits/Ultracurve/Behringer target curves.html

The sound just become so much more “right”. The deep bass was still there but with much better integration, definition and control, not congested like a lump of mud before.

The mid-range presence became so much more real, a sense that the music conveyed/reproduced had more of a “concert” than a “hi-fi” setting.

However, the changes wrought in high frequencies were not too significant though.

Overall the improvement I would quantify upon my system as around 20% to 30%, which = HUGE in my book. Just for you to get a sense of my rating system, to me in general:

Improvement from cables (interconnect, speaker, power cords) rarely exceeds 10%

Improvement from over-sampling CD to non-oversampling is around 10%-15%

Improvement from going solid state to EL34 or 300B tubes (no KT88 please) is around 20%-30%

So you can now see IMHO the UC8024 indeed, effected a very significant and worthwhile sonic improvement in my system.

To conclude - after using UC8024, I am bravely sticking my neck out here but (ok, shoot me down if you want to ^_^), NO subwoofer can be set up correctly without the assistance of a room correction device such as the UC8204 - no matter what setup method you use.

- the reason for my making this statement is quite simple. For every room, there exists a fairly strong room mode that any subwoofer cannot fill in the missing low bass without also boosting the bass at the room mode frequency.

e.g. my room has a 35Hz room mode, which means I have a lot of bass around 35Hz (i.e. too much due to the existence of the room mode) but too little bass around 25Hz or 45Hz (i.e. too little as my main speakers cannot go so low).

Hence, when I put in my Rel sub-woofer (it goes down to around 25Hz), although I can fill up the missing bass around 25Hz and 45Hz, I also exacerbate the room mode at 35Hz as the subwoofer is unable to only ADD bass at 25Hz and 45Hz and REDUCE or Not ADD at 35Hz, well that is, not until the arrival of UC8024…

UC8024 before and after tweaks

The digital IN/OUT is quite a lot better than the analog IN/OUT. The stock analog IN/OUT makes the sound a bit too edgy, thin and bright.

But in stock form, even just using the digital input, the sound is a little too “digital” for my liking.

I then upgraded most of the small electrolytic caps to OSCON, the large power supply caps to Panasonic FC and the LM317 regulator to LM1085-ADJ.

The has improved the UC8024 quite significantly and made the sound noticeably smoother, warmer so it was well worth the effort.

If you do not plan to use the analog IN/OUT, you do not need to read any further. The modification up to this stage is good enough for day-to-day use already. There may be a slight sonic degradation from adding the UC into the chain (~5%), but the sonic improvement wrought by the UC far outweighs (~20-30%) this.

The stock analog IN/OUT is another story, it degrades the system by at least 10-15% overall. It is dry and harsh, the typical “digital” sound. It cannot (IMHO) be recommended for day-to-day use.

After performing the mods as suggested by Thorsten (except the S&B 410 line balanced transformer, a bit too expensive, maybe added later), and adding an additional transformer for the power supply, the analog input can now at least perform on par with the digital IN/OUT, and can now be recommended for day-to-day use.

Please note that changing the LM6172 opamps (in DIP format) to SIL format is NOT easy, and you have to change 6 of them, so be prepared and set aside a good long Sunday afternoon.

The setup of the UC8024

You really need to read and re-read the manual. It was written by engineers for engineers – say no more.

For digital IN/OUTs, if you have coaxial digital IN/OUTs in your system, make yourself two special digital cables by following Thorsten instructions:

http://f3.grp.yahoofs.com/v1/oM_2Pk46OXJ6k4jVW3BSj0fKMse85QxptG4AVYw32sc5_FaldbCjucZ59gbVjsq6O-Qx98akFJi27qKB/TL Circuits/Ultracurve/Behringer digitally interface to SPDIF.html

If you have balanced digital IN/OUTs in your system, you are fine.

For analog IN, you MUST make sure the analog IN of the UC8024 receives a high level signal (I tweaked my CD so the output is 6V p-p at digital max (0dB)). You can check the input level by using the “Meter” function on the UC8024, if the meter only shows -10 to -20dB at digital full scale, this input level is way too low for UC8024 and you will lose resolution.

For analog OUT, you probably will need to attenuate the output of UC8024, as the pro audio level output voltage of the UC8024 unchecked, will most likely drive the input of the consumer audio gear into clipping. The solution is to build a simple voltage divider into the interconnect with a ratio of usually 1:2 or 1:3, the quality of the resistor used will matter here.

Product Weakness: Difficult to set up. Need to tweak it in order to use it on a day-by-day basis.
Product Strengths: Fix bass problem, improve bass definition and mid range presence, turn your room into a perfect room.

Associated Equipment for this Review:
Amplifier: Edison EL34 PSET
Preamplifier (or None if Integrated): S&B TVC TX102
Sources (CDP/Turntable): Non-oversampling Arcam Alpha 5
Speakers: Audio Note AN/K SP
Cables/Interconnects: DIY silver foil and DIY Litz
Music Used (Genre/Selections): Classical, POP and Rock and some Jazz
Room Size (LxWxH): 4.5m x 2.5m x 2.8m
Time Period/Length of Audition: a few months
Other (Power Conditioner etc.): Balanced Power with Jon Risch filter.
Type of Audition/Review: Product Owner

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Topic - REVIEW: Behringer Ultra-Curve Pro 8024 Other - Pat Wen 22:43:32 06/23/03 ( 6)