I’ve recently made over loudspeakers of this well-known brand
. They sound very specific, the bass is very vigorous, good midrange, bright and ringing treble. Not my cup of tea.
Measurements showed that bass is 8-10 dB too high. There is no rear chamber on the midrange speaker, open design, which makes the speakers sensitive to location in the room, and they definitely should not be placed near the back wall. Tweeter had an aluminum dome. Treble exceeded normal values.
After disassembly it turned out that the parts inside were loose. Coils were not properly fastened in the filter – they were hanging on the wires. Acoustic terminals were dangling. Three out of four terminals were not tight. The owner complained that sound was sometimes lost, although the loudspeakers were only a few years old. Holes through which the wires go from the closed box into the open part of acoustic system must be sealed from the inside; on one speaker this hole was sealed by plasticine, but it was missing in the second loudspeaker. I thought it might have fallen out, but it seems it had never even been there.
What was done:
1. Tweeter was replaced by ScanSpeak Illuminator D3004/662000
. I know it well and was confident in the good result. Filter was adjusted to the tweeter. Since the owner liked the overall timbre balance I did not make any major changes in the filter – I only adapted the tweeter to this filter. I could have aligned the midrange, but this would change the bass which the owner liked.
2. I sealed the holes where plasticine was missing.
3. Most importantly, I closed the chamber on midrange speaker. Initially the back wall was covered by a box of racks (like grill) 10 cm thick, jacketed by acoustic fabric. Therein I installed rubberized plates and acoustic damping material. I closed holes on all sides. But I saved the open design and did not completely cover the chamber – but still these improvements eliminated superfluous room reflections, and made the loudspeakers more universal.
4. I fastened all the acoustic terminals and other loose parts inside.
Listening showed that the sound became much smoother, voices became natural, without harsh sibilants. The scene remarkably improved. The sound does not get annoying even after long listening. Still, signature features were preserved just as the client requested.
Unfortunately, many photos were lost, so I can only post what I have left.
Author: Timur Sheykhov