This is a review, listening tests, EQ and detailed measurements of the Fluid Audio C35BT active monitor speaker. It was sent to me by the company and costs US $139 for a pair.
Despite its ultra low cost, the C35BT manages to look professional in its overall look of the drivers. The give away that it is also targeted toward consumer market is inclusion of Bluetooth, headphone and aux input jacks plus combo volume and source selector. This crossover marketing extends to the rear:
I was surprised to see both balanced and unbalanced inputs and such features as auto stand-by. And further by inclusion of the power supply so you don't have a big brick sitting outside.
Only a pair of wires transmit audio the slave channel, indicating that the speaker has passive crossover. Wouldn't expect more at this price point but is useful thing to look for in active monitors. Inclusion of amplification doesn't automatically mean bi-amping and active crossover.
Fluid Audio C35BT Speaker Measurements
The C35BT was subjected to my standard measurement system of Klippel NFS giving us standardized frequency response measurements among others. Let's start with our anechoic response:
We seem to have a couple of major issues below 2 kHz. There is a highly pronounced resonance between 1 and 2 kHz and we have a dip in upper bass, midrange and lower treble. A look at the near-field response explains what is going on:
The port is tuned rather high, causing the peaking. There is a very strong resonance coming out of the port as well which explains that peak. The woofer output seems to keep going making me wonder if it doesn't have a low pass filter. Surprisingly, that did not disturb the overall response much when combined with the tweeter.
Early window shows that the resonance is a pronounced issue:
As is the dip when combined with on axis:
Horizontal directivity shows that the tweeter waveguide is helping some:
Vertical directivity is narrow so stay at tweeter axis:
I was impressed by the power handling, showing little audible issues at 86 dBSPL and even 91:
At 96 dBSPL, it had very audible artifacts so I chose to not continue testing at that level. Note that the best response was had with the front volume control set to max and adjusting the input level. The reverse would make the front end compress resulting in horrible artifacts even at low SPLs (a common signature among this class of monitors).
Waterfall naturally shows resonances:
Fluid Audio C35BT Listening Tests and Equalization:
To be up front, my first reference track sound poor. I think this was accidental as later testing without EQ on other material sounded much better. Knowing the resonance needs fixing, I went after that first:
Being at such a specific frequency, it would naturally interfere with the right content. Taking that down helped some but I still did not like the sound until I looked at the PIR and realized that we have fair amount of spectrum attenuated. So I tuned the second filter around 300 Hz. Once there, nice amount of warmth came back and overall fidelity nicely crossed my threshold of what is a hi-fi speaker.
Mind you, the hump around 100 Hz would at times make the sound boomy. Optimizing that requires in-room measurements, not something I can do with just anechoic measurements. Trying anyway, I liked the attenuated response there with some content and not others. While the bass would become less boomy, it lost some of the impact that this little speaker can deliver.
Conclusions
Such low prices must put severe restrictions on what a speaker can do especially when it is loaded with useful features such as balanced inputs. I wish something was done to at least attenuate that strong resonance. And better tuning of the port. Despite how much the anechoic response bothered the eye, correction turned out to be quite easy and took only a couple of filters. This turned my opinion completely around.
Per above, I can only recommend the Fluid Audio C35BT if you use equalization. Without it, it doesn't sound offensive other than the 100 boost. So maybe it is OK for secondary use but you owe it to yourself to apply some EQ. A DAC with some EQ would nicely finish this system to a respectable level.
------------
As always, questions, comments, recommendations, etc. are welcome.
Appreciate any donations using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
Despite its ultra low cost, the C35BT manages to look professional in its overall look of the drivers. The give away that it is also targeted toward consumer market is inclusion of Bluetooth, headphone and aux input jacks plus combo volume and source selector. This crossover marketing extends to the rear:
I was surprised to see both balanced and unbalanced inputs and such features as auto stand-by. And further by inclusion of the power supply so you don't have a big brick sitting outside.
Only a pair of wires transmit audio the slave channel, indicating that the speaker has passive crossover. Wouldn't expect more at this price point but is useful thing to look for in active monitors. Inclusion of amplification doesn't automatically mean bi-amping and active crossover.
Fluid Audio C35BT Speaker Measurements
The C35BT was subjected to my standard measurement system of Klippel NFS giving us standardized frequency response measurements among others. Let's start with our anechoic response:
We seem to have a couple of major issues below 2 kHz. There is a highly pronounced resonance between 1 and 2 kHz and we have a dip in upper bass, midrange and lower treble. A look at the near-field response explains what is going on:
The port is tuned rather high, causing the peaking. There is a very strong resonance coming out of the port as well which explains that peak. The woofer output seems to keep going making me wonder if it doesn't have a low pass filter. Surprisingly, that did not disturb the overall response much when combined with the tweeter.
Early window shows that the resonance is a pronounced issue:
As is the dip when combined with on axis:
Horizontal directivity shows that the tweeter waveguide is helping some:
Vertical directivity is narrow so stay at tweeter axis:
I was impressed by the power handling, showing little audible issues at 86 dBSPL and even 91:
At 96 dBSPL, it had very audible artifacts so I chose to not continue testing at that level. Note that the best response was had with the front volume control set to max and adjusting the input level. The reverse would make the front end compress resulting in horrible artifacts even at low SPLs (a common signature among this class of monitors).
Waterfall naturally shows resonances:
Fluid Audio C35BT Listening Tests and Equalization:
To be up front, my first reference track sound poor. I think this was accidental as later testing without EQ on other material sounded much better. Knowing the resonance needs fixing, I went after that first:
Being at such a specific frequency, it would naturally interfere with the right content. Taking that down helped some but I still did not like the sound until I looked at the PIR and realized that we have fair amount of spectrum attenuated. So I tuned the second filter around 300 Hz. Once there, nice amount of warmth came back and overall fidelity nicely crossed my threshold of what is a hi-fi speaker.
Mind you, the hump around 100 Hz would at times make the sound boomy. Optimizing that requires in-room measurements, not something I can do with just anechoic measurements. Trying anyway, I liked the attenuated response there with some content and not others. While the bass would become less boomy, it lost some of the impact that this little speaker can deliver.
Conclusions
Such low prices must put severe restrictions on what a speaker can do especially when it is loaded with useful features such as balanced inputs. I wish something was done to at least attenuate that strong resonance. And better tuning of the port. Despite how much the anechoic response bothered the eye, correction turned out to be quite easy and took only a couple of filters. This turned my opinion completely around.
Per above, I can only recommend the Fluid Audio C35BT if you use equalization. Without it, it doesn't sound offensive other than the 100 boost. So maybe it is OK for secondary use but you owe it to yourself to apply some EQ. A DAC with some EQ would nicely finish this system to a respectable level.
------------
As always, questions, comments, recommendations, etc. are welcome.
Appreciate any donations using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
