LDC & SDC mic test (not blind)

[Emmathom]

Before selling some of my microphones I thought it would be interesting to compare them thru an audio test and save a sound sample of them. This test consists of recording a voiceover and a folk guitar. Since most of them are DIY I added an official brand mic as “reference”. These mics are all cardio (or set to cardio for this test) :

SDC :

• c251(DIY PCBA + Superlux S502MkII capsule / no OPT)
• S502 v1 (MicUlli’s PCBA / no OPT)
• Warm Audio WA84 (100% stock / OPT)
• Shure SM81 (100% stock / OPT) > reference mic

LDC :

• t.bone SC1100 (Ari K47flat + DIY PCBA + Monacor LTR-110 2:1 OPT)
• 6AK5 (AliExpress K47 + EF95 tube + DIY PCBA + Tamura 10:1 OPT)
• Studio Project TB1 (797audio capsule + 6072 NOS + mod. PCBA + stock OPT)
• Neumann TLM193 (100% stock / no OPT) > reference mic

I then thought about a recording protocol. I decided to use the 4 mic/line inputs of my sound card (Presonus 1810c) and not my external tube preamps so as not to risk coloring the sound and distorting this test. Here are the technical specifications of this sound card as well as some information on the types of inputs. I chose this interface because of its 4 “real” line inputs directly connected to the ADC and this without going through the preamps.





I first calibrated the line inputs by injecting a 1kHz signal from my smartphone into each channel and thus aligning them to obtain a signal calibrated at -12,7dB with a gain potentiometer set at ~3:00PM (7:00AM is gain pot set to 0 so -15dB / 7:00PM is gain pot set to max. so +65dB). I measured 160mV at smartphone output to obtain this level. This 3:00AM pot. position corresponds to an average level setting for static mics in my audio cards.

Then, with these same gain settings for the 4 channels, I recorded a short and quite loud acoustic strumming guitar sample in order to measure the output level differences between each microphone. Here they are :

SDC (with 1kHz@-12,7dB for all 4 inputs) :

• DIY c251 = -9,1dB
• Superlux S502 = -8,8dB
• Warm Audio WA84 = -3,6dB
• Shure SM81 = -14,5dB

LDC (with 1kHz@-15dB for all 4 inputs) :

• t.bone SC1100 = -4,6dB
• DIY 6AK5 = -9,6dB
• Studio Project TB1 = -7,2dB
• Neumann TLM193 = -17,8dB

At last I adjusted each level separately to get the same recording level on each channel with each mic. In both test sessions the mics capsules were of course aligned so that they were at the same distance from the source, i.e. 3 feet (~1m) for acoustic guitar and 1 foot (~30cm) for voice over. A pop-filter was used for voiceover.

 

[Emmathom]

After recording each session I sent again a 1kHz tone to the four inputs to check which levels were set and here are the measurements :

SDC’s session :

• DIY C251 = -13dB
• Superlux S502 = -12,9dB
• Warm Audio WA84 = -13,8dB
• Shure SM81 = -12dB

LDC’s session :

• t.bone SC1100 = -16dB
• DIY 6AK5 = -14,5dB
• Studio Project TB1 = -15dB
• Neumann TLM193 = -12,4dB

Finaly, to export the tracks I did some tiny adjustements (by fader only > from +0,6dB to -1dB) to have about the same output level for each track. I recorded the files in 24-88,2 and exported them in 16-44,1.

Here are the SDC's samples :

SM81-voix c251-voix S502-voix WA84-voix
SM81-guitar c251-guitar S502-guitar WA84-guitar

 

[Emmathom]

And here are the LDC's samples :

TLM193-voix SC1100-voix SP-TB1-voix 6AK5-voix
TLM193-guitar SC1100-guitar SP-TB1-guitar 6AK5-guitar

During this I noticed a "100Hz hum" in the Studio Project TB1 > got to be fixed. Sorry.

All files are synchronized (SDC's together and LDC's together) and can therefore be imported into a DAW for comparative mute/solo playback.

I beg your indulgence for the timbre of my voice as well as my mediocre guitar playing... but sometimes you have to make do with what you have.

 

[Emmathom]

Some personal notes & opinion :
- the SC1100 sounds very close to the TLM193 to me (and it's my favorite LDC of this test > thanks to the Ari K47 Flat which is a wonderful capsule)
- the Studio Project TB1 is OK but a bit sibilant to my taste (even if I put a kind of de-emphasis / 150pF polyester from plate to ground)
- the 6AK5 is good on (my) voice but too mid on acoustic guitar (that because of the frequency range of my voice ?)
> my prefered LDC is the SC1100

- all four SDC's are good mics !
- the SM81 is really a good reference to me and the c251 shares its qualities
- the S502 is very detailed but lacks a bit of lows and add a bit of highs
- despite its poor building quality the WA84 sounds also great but a bit darker compared to the 3 others
> my prefered SDC is the c251

 

[micolas]

Before selling some of my microphones I thought it would be interesting to compare them thru an audio test and save a sound sample of them. This test consists of recording a voiceover and a folk guitar. Since most of them are DIY I added an official brand mic as “reference”. These mics are all cardio (or set to cardio for this test) :

SDC :

• c251(DIY PCBA + Superlux S502MkII capsule / no OPT)
• S502 v1 (MicUlli’s PCBA / no OPT)
• Warm Audio WA84 (100% stock / OPT)
• Shure SM81 (100% stock / OPT) > reference mic

LDC :

• t.bone SC1100 (Ari K47flat + DIY PCBA + Monacor LTR-110 2:1 OPT)
• 6AK5 (AliExpress K47 + EF95 tube + DIY PCBA + Tamura 10:1 OPT)
• Studio Project TB1 (797audio capsule + 6072 NOS + mod. PCBA + stock OPT)
• Neumann TLM193 (100% stock / no OPT) > reference mic

I then thought about a recording protocol. I decided to use the 4 mic/line inputs of my sound card (Presonus 1810c) and not my external tube preamps so as not to risk coloring the sound and distorting this test. Here are the technical specifications of this sound card as well as some information on the types of inputs. I chose this interface because of its 4 “real” line inputs directly connected to the ADC and this without going through the preamps.

View attachment 146160
View attachment 146161

View attachment 146162
I first calibrated the line inputs by injecting a 1kHz signal from my smartphone into each channel and thus aligning them to obtain a signal calibrated at -12,7dB with a gain potentiometer set at ~3:00PM (7:00AM is gain pot set to 0 so -15dB / 7:00PM is gain pot set to max. so +65dB). I measured 160mV at smartphone output to obtain this level. This 3:00AM pot. position corresponds to an average level setting for static mics in my audio cards.

Then, with these same gain settings for the 4 channels, I recorded a short and quite loud acoustic strumming guitar sample in order to measure the output level differences between each microphone. Here they are :

SDC (with 1kHz@-12,7dB for all 4 inputs) :

• DIY c251 = -9,1dB
• Superlux S502 = -8,8dB
• Warm Audio WA84 = -3,6dB
• Shure SM81 = -14,5dB

LDC (with 1kHz@-15dB for all 4 inputs) :

• t.bone SC1100 = -4,6dB
• DIY 6AK5 = -9,6dB
• Studio Project TB1 = -7,2dB
• Neumann TLM193 = -17,8dB

At last I adjusted each level separately to get the same recording level on each channel with each mic. In both test sessions the mics capsules were of course aligned so that they were at the same distance from the source, i.e. 3 feet (~1m) for acoustic guitar and 1 foot (~30cm) for voice over. A pop-filter was used for voiceover.

View attachment 146164
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View attachment 146167

My picks for guitar tests are:
SDC: c251 Diy
LDC: SC1100 Emmod

 

[jp8]

I listened to all recordings in Audacity. My very subjective and perhaps somewhat biased findings:

SDCs
Overall, I liked the C251 and WA-84 best. The C251 has the most extended frequency range, while the WA-84 adds some warmth, especially on the guitar. Perhaps the C251 is a bit bass-heavy when close-miking, but that does give body to a voice and the sound of the guitar. On fingerpicking-style guitar playing, I might prefer the C251 instead of the WA-84 because I expect it to sound more detailed in the highs.

The S502 was rather thin-sounding. The SM81 lacks character and some low-end but sounds balanced.

LDCs
I found the Neumann somewhat disappointing and not similar to the SC1100. It had a bit of a hollow, unpleasant sound.

The TB1 is too sibilant, indeed. To a lesser extent, the 6AK5 is also a bit sibilant to my ears and not sounding as balanced as the CLEAR winner, the SC1100. This is not the first time I have listened to an LDC with Ari's flat K47 capsule, but in most cases, I liked what I heard: a balanced and lively sound. The more I listen to mics with some "color", the more I start liking "flat" mics like Ari's flat K47. I will definitely buy those capsules when I get to it.

My 2 cents worth: I'm not a musician or a sound engineer, and my ears are a 9.5 kHz LPF. Just saying what I (dis)like.

Jan

 

[Emmathom]

Hi @jp8
I agree about c251 and WA84 : the first is "straight" (very real) and the second adds a "little something" (warmth ?) which is pleasant. The S502 is indeed thinner (but to me it's dedicated to ambiant recording at (say) 2-3m from orchestra). The SM81 is very well balanced to me but indeed lacks of character... but it's a very good mic (lacks output level too by -9dB to -12dB compared to others). The SM81 is often used on hi-hat and snare...

The SP-TB1 is indeed sibilant and gives too much highs (and have a 100Hz hum that I'm fixing now). The 6AK5 despite its very good AliEx K47 capsule is ruined by a serious issue : its headbasket is not appropriate (I will soon move the whole thing in a SC1100 mic which is far more appropriate). The TLM193 is a bit disappointing for the cost (~1300€) : impersonnal, cold, not "sexy". The SC1100 - new circuit + Ari 47flat - is a great mic with a large Fr, character, fidelity.

c251 for SDC (and WA84 in 2nd pos.)
SC1100 for LDC (no 2nd pos. but the 6AK5 thing in the SC1100 mic will be satisfying I'm pretty sure)