This is a review and detailed measurements of the Technics SB-F1 mini vintage bookshelf speaker. It is on kind loan from a member:
SB-F1 was produced in Japan around 1978. It has a stout, diecast aluminum frame. I understand it was quite expensive for its time despite its diminutive size. I got a kick out of the circuit breaker in the back. Had forgotten about these back in the day:
Measurements that you are about to see were performed using the Klippel Near-field Scanner (NFS). This is a robotic measurement system that analyzes the speaker all around and is able (using advanced mathematics and dual scan) to subtract room reflections (so where I measure it doesn't matter). It also measures the speaker at close distance ("near-field") which sharply reduces the impact of room noise. Both of these factors enable testing in ordinary rooms yet results that can be more accurate than an anechoic chamber. In a nutshell, the measurements show the actual sound coming out of the speaker independent of the room.
Measurements are compliant with latest speaker research into what can predict the speaker preference and is standardized in CEA/CTA-2034 ANSI specifications. Likewise listening tests are performed per research that shows mono listening is much more revealing of differences between speakers than stereo or multichannel.
Reference axis was the center of the tweeter (aligned by eye). Measurement room was at 15 degrees C.
Technics SB-F1 Measurements
Acoustic measurements can be grouped in a way that can be perceptually analyzed to determine how good a speaker is and how it can be used in a room. This so called spinorama shows us just about everything we need to know about the speaker with respect to tonality and some flaws:
I don't know why but I expected a very poor frequency response but that was not the case. Response is quite flat and would be at home with many small speakers (and better than many). It does have a tilt up toward the higher frequencies though. And there are a lot of jagged peaks indicating resonances.
Early window is similar to on-axis:
Predicted in-room response as a result is decent:
Power handling was surprisingly good at 86 dBSPL but understandably, falls apart at 96:
Horizontal directivity and beamwidth is good:
Vertically it is messy like a lot of 2-way speakers are. Make sure you are at or slightly above tweeter axis when listening:
Impedance is around 5 ohm which is good for this day and age:
Sorry, forgot to run the CSD/Waterfall test.
Technics SB-F1 Speaker Listening Tests
First impression with female vocals was very positive. Sound was clean with just a hint of brightness. Switching to tracks with more bass though degraded performance fair bit. At very low volumes, it was still very good. But turn up the volume and there is a nasty resonance that is quite audible. Turn it up more and the sound gets very muddy with distorted bass. You could argue this is to be expected but I could not get past the resonance.
FYI I could clearly hear the resonance in the frequency response sweep during testing at 96 dBSPL.
Conclusions
I am impressed with level of engineering that went into the design of SB-F1. If it didn't have that nasty resonance, it would be highly competitive even today. But with it and the limited power capability, I can't see a good reason to recommend it.
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As always, questions, comments, recommendations, etc. are welcome.
Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
SB-F1 was produced in Japan around 1978. It has a stout, diecast aluminum frame. I understand it was quite expensive for its time despite its diminutive size. I got a kick out of the circuit breaker in the back. Had forgotten about these back in the day:
Measurements that you are about to see were performed using the Klippel Near-field Scanner (NFS). This is a robotic measurement system that analyzes the speaker all around and is able (using advanced mathematics and dual scan) to subtract room reflections (so where I measure it doesn't matter). It also measures the speaker at close distance ("near-field") which sharply reduces the impact of room noise. Both of these factors enable testing in ordinary rooms yet results that can be more accurate than an anechoic chamber. In a nutshell, the measurements show the actual sound coming out of the speaker independent of the room.
Measurements are compliant with latest speaker research into what can predict the speaker preference and is standardized in CEA/CTA-2034 ANSI specifications. Likewise listening tests are performed per research that shows mono listening is much more revealing of differences between speakers than stereo or multichannel.
Reference axis was the center of the tweeter (aligned by eye). Measurement room was at 15 degrees C.
Technics SB-F1 Measurements
Acoustic measurements can be grouped in a way that can be perceptually analyzed to determine how good a speaker is and how it can be used in a room. This so called spinorama shows us just about everything we need to know about the speaker with respect to tonality and some flaws:
I don't know why but I expected a very poor frequency response but that was not the case. Response is quite flat and would be at home with many small speakers (and better than many). It does have a tilt up toward the higher frequencies though. And there are a lot of jagged peaks indicating resonances.
Early window is similar to on-axis:
Predicted in-room response as a result is decent:
Power handling was surprisingly good at 86 dBSPL but understandably, falls apart at 96:
Horizontal directivity and beamwidth is good:
Vertically it is messy like a lot of 2-way speakers are. Make sure you are at or slightly above tweeter axis when listening:
Impedance is around 5 ohm which is good for this day and age:
Sorry, forgot to run the CSD/Waterfall test.
Technics SB-F1 Speaker Listening Tests
First impression with female vocals was very positive. Sound was clean with just a hint of brightness. Switching to tracks with more bass though degraded performance fair bit. At very low volumes, it was still very good. But turn up the volume and there is a nasty resonance that is quite audible. Turn it up more and the sound gets very muddy with distorted bass. You could argue this is to be expected but I could not get past the resonance.
FYI I could clearly hear the resonance in the frequency response sweep during testing at 96 dBSPL.
Conclusions
I am impressed with level of engineering that went into the design of SB-F1. If it didn't have that nasty resonance, it would be highly competitive even today. But with it and the limited power capability, I can't see a good reason to recommend it.
-----------
As always, questions, comments, recommendations, etc. are welcome.
Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
