Tuesday, September 22, 2009

Is It Safe To Eat The Outside Of Salami?

UREI / Universal Audio 1176LN compressor for 200 € The proof! Do-It-Yourself Test & Review Part 2 / 3



Here, as promised, part 2 of my dissertation. Feel free to Comment.


part 1: Basic information and facts about the devices



part 2: The comparison, analysis, summarized


part 3:
survey statistics, audio samples, Sources, building instructions

complete thesis in PDF format (without audio)



complete thesis in PDF format (including audio)

enjoy reading and perhaps even himself recreating: D

Part 2: The
Comparison, the evaluation concludes third
Comparison of the two compressors


For comparison of the two compressors has resorted to a Universal Audio 1176LN

, which unanimously in the industry is seen as a worthy remake of the original UREI
. "The exact replica of the 1176LN offers the legendary assertive compression characteristics and the noble vintage sound, the keys to the success of the original [!] Are responsible"


According to statements from Universal is sound technically no difference to the original.

"All three available versions, [...] design, are based as close as possible to the original, with no attempt to simply Modernise the much sought after original. The unit is assembled using hand-wiring technique and is tested to match the original in every way achievable. "



3.1 The structure


was aware of the production of the replica waived optical equality. This is for the limited budget, but sometimes also technical refinements of the original debt.
was


In the replica of a ratio selection by snap buttons on the complexity of the design omitted. With commercially available probes, an optically identical version would have been possible, but they remain locked in contrast to the model, which would mean that you should turn off each switch before choosing a different ratio for the first stage again. The ratio was selected in the reconstruction as a rotary switch in grades 4, 8, 12, and 20:1 realized. An upgrade to the popular all-buttons-in-Nuke, slam or British fashion, however, is also using this clever wiring a double-deck rotary switch possible.


3.1.1 Selection and quality of the components



As As indicated in 2.2.5 was on the accuracy of the values of the used resistors placed a high value. It was not possible to also check out Zeitgünden all capacitors and active components on its quality. After a test function, were used by the specified ratings, although it had to tolerances of up to 20% will be accepted in this context.

The wiring and soldering of the devices was the best of our knowledge and belief, however, carried out in accordance with amateurish. Here, a very inferior quality in comparison to the model not be denied. Exactly in this point, the replica differs significantly from the original. Since all devices from Universal Audio
be hand-wired, it can be assumed that one can thereby take the utmost care. The selection of components is certainly made similar meticulous as the existing clone. A statement from Universal Audio this was even after several attempts to get.



It is likely that the relatively high sale price of the unit of about 2000 € not even in supposedly expensive materials or development costs justified. Rather, he is to be interpreted as a sign that a very large expenditure of time, due to the manual manufacturing and thereby required precision is in the selection of components as needed. This is supported by the data collected during the manufacturing experience of the author of this thesis.


3.2 In theory


Below are shown different results. They are all, unless otherwise stated on produced by using ProTools
white noise that was sent with the same level on both devices. The resulting images were evaluated with freely available FFT software FuzzMeasure
. The next graph shows the result of frequency analysis with a Smoothing of a third octave. The red frequency response shows the impulse response of Universal Audio compressor, the blue of the replica.





Figure 08: Frequency response red: original, blue: reconstruction

In this diagram illustrates the drop in the frequency response of the replica from 10kHz, while the original in this area quite linear. Furthermore, the soft frequency responses of both compressors in the range of 20Hz to 800Hz from some cases up to 3dB of each other, while between 1kHz and 10kHz almost congruence.

in the journal Professional Audio published frequency responses also show that the original exhibits in the heights above 30kHz even an increase of almost 3 dB.





09: yellow: compression, red: no compression



This frequency increased, in the investigations of this work not be considered because during the recording of the analyzed signals were sampled at 44.1 kHz. The analysis of the magazine shows, however, that the difference between the two devices in the frequency response from 10kHz up is more serious than first thought.
The slight increase below 20 Hz is found and confirmed again in this diagram created with FuzzMeasure data.

Below are shown two diagrams represent the phase response of the devices. It is striking that the original 1.5 kHz, the phase begins to shift the audio signal.







Figure 10: Phase response of the original




is clear that the reconstruction phase starts already at about 400 Hz shift. This However much is done to 10kHz frequency-selective than the original.
Figure 11: Phase response of the replica
3.3 In practice
Below are investigated dynamic limiting and regulating the behavior of both compressors. Since the time parameters of both devices there is no screening, often extreme settings have been selected to compare. Only when the potentiometer on the stop, the fair comparison is given the maximum or minimum possible. It is requested that in mind that some settings do not make sense musically, but very well show the limits within which to work with both devices is possible.
3.3.1 Dynamic boundary
The following picture shows a section of a bass solo in the test files to the survey, but this was the input of both compressors run over. The complete signal is in the compression. The input is turned up to 70%. With a ratio of 20:1, the signal with the settings Attack fast and slow release compressed.


12: top: Original, below: it can be seen replica
The original goes to courageous thing, and can thus provide a more constant level curve and less dynamic.
3.3.2 control speed

The manufacturer's specified speeds are usually in the following limits: 20 - 800 microseconds Attack (100% recovery), 50-1100 milliseconds Release (for 63% recovery)

The differences in the shortest possible attack times of the compressors are rather clear, however, against the expectations of the author. The following image is the song to see 2 of the survey sample. In the upper part of the behavior of the original
1176, at the bottom of the planting. The values set on the compressors were Attack: very fast, Release: medium, ratio 4:1.





Figure 13: Top: original, Bottom: reconstruction

It is clear to see that the reconstruction significantly different on the transient response and that more blurred as his role model.

looks similar because of the release time. The following image was also singing to the example 2 (male) were used in the survey. Above is again the original, the replica shown below. The settings of the compressors were as follows. Attack: very short, medium release, ratio 4:1.


14: Top: original, Bottom: reconstruction


It's clear that building a replica takes longer to recover than the original. The control times the original settings are in the extreme so much crisper and more reliable work. However, it should be in this example, not be neglected, which may appear even with meticulous adjustment of the same settings on both compressors, inaccuracies.


3.3.3 Special sound quality


In the following is an exemplary of 1kHz sinewave shown that the reconstruction of much more at this frequency harmonics, thus causing distortion than the original. It is likely that this difference over the full frequency response, but due to lack of data are not used.



15: red: original, green: replica

Furthermore, it is shown that the actual distortion factor of the replica are much higher, since the Frequency response of transformer also filter as a low pass.

Another diagram of the journal
Professional Audio
shows that the aggressive and-present sound of the Universal Audio 1176LN
by his sometimes strong distortions and hence high total harmonic distortion of up to 6% justified.

16: green: compression, blue: without compression


In the period from 11/03/2009 to 02/04/2009 was on the free survey platform
http://voycer.de
a blind comparison in German and English online, is to verify that apart from technical and measurable differences between the tested devices and audible differences to detect.

Subjects had by so-called screening questions to qualify for this survey. This term comes from market research and to ensure that people only participate in surveys, which are the target group to be analyzed. In this case, the questions were S3 and K1. The first clarifies the profession. There were only analyzed responses from people who reported exercising sound engineering as a hobby or profession. Question K1 ensures that respondents feel safe in dealing with and in the operation of compressors. Crossed a respondent in one of these issues, the negative responses "
, nor
" or "Not very
" to, all other answers were withdrawn from the competition.

have competed in the above mentioned period 113 people in the survey. Of these 102 people could qualify. All results were evaluated as a percentage. For the listening test different mono signals were processed with the original and the clone. This was done by insertion can both compressors to a
ProToolsHD96
interface. Both units received the same signals and were set identically. The output was recorded in each case with 24-bit and 44.1 kHz in the software
ProTools.
Meticulous attention was paid to accurate calibration of both devices to rule out differences in volume.
The role of the qualified subjects was, without knowing what files the original and which were processed with the replica to discern differences and to opt for the particular example from which they believed that it was processed with the original . They should take their sound impression as a basis for its decision. Could they will hear any difference, or do not choose, they could also indicate that.

the complete questionnaire and all the evaluated statistics and charts are in Annex B and C of this work. Since the complete analysis all the results of this survey is beyond the scope of this work, the profound interpretation of the collected data is left to the reader himself. However, it is discussed below on the most relevant results, and differences were trying to portray.


is controversial enough, probably the most significant finding of the listening test the indecisiveness of the test subjects. Only in very exceptional circumstances could the tester with an absolute majority, agree on the original. Consistently offered the original and replica, a head-to-head race for the attention of listeners. In rare cases, such as the listening test "Kick Drum 2" did a majority of 54% for the original. Often becomes apparent that almost a fifth of all respondents could not specify a file, but for the answer "I do not hear a difference," decided.

With 45% believe most people the most significant differences in language and song to hear. These are by far the most sensitive signals in the audio processing, therefore, not surprising that decision. More surprising is that in these examples could also be a clear assignment of the subjects.

decided with 40% for most of the listeners the different frequency response than trend-setting difference. It is striking, however, that the more extreme settings were elected to the compressors in terms of compression ratio and the control times, the more the subjects typed correctly. The differences may therefore be included more on the longer routes and control of the more divergent dynamics limit, as if it is diverging frequency responses. 36% of respondents saw it that way.


The most exciting answers and instructions to carry out the differences were partly M8 in the open question. Open because it was a text field where the testers had 2500 characters available for their impressions to be brief in words. This question is difficult to evaluate comparable, so the subjects are selected quotes below to read. This stand alone and are separated to see the comprehensive statistics.

"One compressor had marked increase in high frequencies and less low-mid range. It suited different things better. Let's call the one with less RF and more low mid the original and the one with more HF and less low mid the copy. "


" The original Urei has a decent amount of waste, without sounding muffled. I find this especially votes in an asset, as S-sounds do not sound as sharp and smacking into the background. "

interesting to note appears that both the reproduction identify subjects due to lack of height incorrectly as an original. The majority the tester judged the differences in M8 as subtle.


addition, the subjects rated the most out of listening to differences in question M1 as serious.


fourth evaluation of the comparison


Below are the results of all observations collectively and Facing explained. One must work out the essential features of both devices, and for defining minor of the findings. It will also attempt possible causes for the differences encountered designate, even in cases it can not be presented more evidence.
4.1 Evaluation of results

The measurements have shown that the original and replica in terms of frequency response, phase response and distortion partly strong, partly differ less from each other.


The original has a best frequency response with a slight increase beyond the upper human listening frequency. The reconstruction is by contrast an impulse response - a low-pass first Resembling order - to, as it is filtered from 10-12kHz with about 6 dB / octave. Both facts show that the respective devices are used for different purposes sometimes more or less suitable.

confirmed the measured low-pass filtering of the replica in the paid 2.2.4 forecast that in this case when the output transformer made savings of € 40 is exposed. If installed at this point the initially planned transformer company
Lundahl
is assumed that the low-pass filtering of the replica in favor of the original frequency response cancels.


looks similar with the observed distortions. Since the original is known for an assertive, present sound to have a reconstruction can not necessarily assume that it would sound bad due to a higher distortion.

The results of the distortions in the 1kHz sine wave, can be suspected from their appearance that they are due to freezing transistors. A distortion of an overdriven transformer is more likely to back a tape saturation. Similar to the original distortion occurring. Either the work area, called the bias of the FET is not set correctly, the quality of the original
BF245A
is much better than the original or the other built-in transistors, for example, the
Darlington pair
of the output amplifier lead to these distortions . This, however, no evidence is available.

The earlier onset of phase shifts are known to be due to capacitors and inductors and are therefore most likely due in large tolerances of the components and the alternative use exchangers.

2.4 sound differences


By far the most prominent perceived by the testers and emerged most clearly in the measurements of the height loss of the replica is compared to the original.


The control mode of the replica differs in speed and scale in part on a model, which can be seen not necessarily as a sound difference.

well but the distortions. They give both the compressor characteristic bite, the required presence and enforcement capability.

4.3 Before and disadvantages of each compressor


The advantages of the original are obvious. It's name, the reputation, reliable quality in the production of the device by
Universal Audio
. But besides these general features of the device properties it is mainly through his brilliant frequency response, are incomparably fast control response and the unique handling of transients. All these factors make the 1176 the first choice when dense, crunchy sounds are asked if brilliant, strong voices can be expected and if there happy times may be a bit over-compression and to radiate the sound.

The list of disadvantages is nevertheless at least as long as the benefits. There is for one of the offered for the performance but rather high purchase price for a mono compressor excessive space of two rack units and even the characteristic sound. This device is visible to its characteristics as a sound-Dyer is not always the first choice but deliberately and consciously. When it comes to natural reproduction of sounds, the compressor should be better removed from the signal chain. For smooth pop vocals with unobtrusive transients and soft upper part of this device seems rather inappropriate.

Right here plays a replica of its strengths. The first as a disadvantage perceived and slightly damped frequency response makes loud statements of listeners interfering s-sounds intrusive, voices and instruments gives softer highs, making it smooth without sacrificing the very typical presence region and to use the sound-shaping distortion of excessive influence. It is likely that remain present with the replica of processed signals in a mixture without screaming it. It seems the signals are thus easier to handle and easier to control.
The reconstruction offers based on the individual configuration options more leeway what dimensions, equipment and design concerns. It is for example possible to build something with our own creativity, a switchable stereo version of the 1176, as required, in a single rack. The space savings thus achieved is not to be underestimated in limited space in control rooms.

The price of the planting of about € 200
is probably his most convincing argument, though the invested work hours were not counted.

But the replica has its drawbacks. The unpredictability in the sound of the replica makes each individual unique. Reproducible results are difficult to . Realize He packs do not or only under extreme settings as reliable and mercilessly as the original. The more extreme these settings are, the further away one is from the model, even if alone, the clone compressor still considered a properly sounding studio tool.

5th Conclusion

was the basis of this study demonstrated that it is possible for electrical laity to build with relatively little financial cost to name a
1176
worthy compressor. This should serve as an example for all analog studio equipment. This work is Courage to make, to question the technology and demonstrate that it is possible to produce millions of investment even without studio equipment that the beloved and revered cult objects must be inferior to nothing.

It is not the original, it was assumed. It was eventually planned in advance to make an amateur replica.
If we take into account that frequency response and distortion control behavior marginally, subtle, according to statements of many subjects deviate from the model, we obtain for a tenth of the price, in my view 90% UREI
.

It was hard to spot differences. And in direct comparison. If you imagine the reconstruction once before in everyday studio operation, it quickly becomes clear that all measurements and listening tests and comparisons are irrelevant. Look for the right sound, it is more or less to 2dB in the frequency response or 1% more or less distorted even more. A device must function in the required situation with the context and achieve the desired results. If it does not, take another one. Whether
UREI
,
Universal Audio
or do-it-yourself-
it is. In the studio is demand-driven to act, "service on demand" so to speak. Do I want more distortion? Will I heights less? Do I want to "go against the wall", the signal or only slightly ankomprimieren? Depending on the objectives you will always decide otherwise. Accordingly, making the range of alternatives ways the real quality of a studio. As with microphones.

If you want to have it from as well-known and expensive equipment in his studio to show: I can not afford the original! One will certainly not happy with the replica. If, however, for very little money to enjoy the worship and sound so much is not one around it, to deal with the question of what is really inside the devices.


This work has been worthwhile, in my view in any way, both financially and to gain experience, understanding of technical and musical relationships and enriching the personal instrument collection.
But behind all this, one should always ask the question, it is to use the technology or the creativity in the way it that limits our options? to clarify this question was not objective of this work, because everyone will have to answer for themselves.

END PART 2








part 1:
basics and background information on the devices


part 2:
The comparison, analysis , the conclusion

part 3: survey statistics, audio samples, references, building instructions



complete thesis in PDF format (without audio)


complete thesis in PDF format (including audio)


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