Spendor S3/5SE advice

[PeterLeest]

I bought a pair Spender S3/5 SE, during the initial run-in period, the sound stage and tonal balance is very good.

However, after few months of run-in, the treble seems to be reduced quite substantially; and it sounds dull.

Is this normal? Any ways to improve high frequency response (like changing the crossover)?

[Salas]

It is supposed to have a mellow top octave power response, but to the extent of sounding really dull after a period, I would check if both tweeters are working OK first.

[PeterLeest]

The top octave sound dark and uninteresting when it is compared to a Dynaudio contour 1.3 mk II.

I experiment the crossover and reduced R1 to 4.7¦¸; also, I swapped the tweeter terminal so that the tweeter and woofer are out of phase. With these changes, it sound lively and the tonal balance is now comparable to that of the Contour.

What is the net effect of the R1 change? Did I boost or decrease the top octave freq response, is it a right move?

[Salas]

One can never guess if the full technical analysis isn't available. This is proprietary to the designer, and it takes to reverse engineer for a third party so to exactly know. From what you did, it looks like that all drivers are working OK, and you have found a subjective balance to your liking. I cant add any further comment without full data.

[Inductor]

The change from 5R6 to 4R7 doesn't make 'any' difference. So maybe the tweeters were not properly connected in the first place, and should be as (you show) in the plan.