JBL 3677

[FairPlayMotty]

Three for sale in the UK.

https://www.ebay.co.uk/itm/276283621267 ... R6inzIahYw

[matthias]

Have you finished outsourcing the crossover to the box? What are your impressions, was there an improvement?

See ML's answer here:

viewtopic.php?p=66243#p66243

[Masi]

AFAIK, ThomasOK and Music Lover made the complete wiring replacement.

That's correct and I also moved the X-overs to an external box, placed on the Harmoni (Alu) Mimer
Quite a bit better actually.
The external box was a bigger step than the wiring imho, and the wiring was a good bit better than the original 3677 . Both highly recommended.
The Harmoni Shelf doing something "just right" regardless what you place on them.

That I understand correctly, the crossover was removed and installed in the box and rewired, and in particular the cable from the crossover was soldered to the chassis connections. Okay I got it. Somehow I remember that someone had completely rebuilt the crossover with high-quality mundorf components, but then a certain flair was lost.. (If I so remember correctly).

What are your thoughts on completely rebuilding the crossover with high-quality components? Here is a diagram of the crossover of the JBL 3677. I think the fact that JBL publishes this alone supports the company's sympathetic approach.

https://www.audioheritage.org/vbulletin ... mp-speaker

[matthias]

What are your thoughts on completely rebuilding the crossover with high-quality components?

I left my 3677s in their original state.
In rebuilding a crossover you have so many variables that the risk is high ending with an unmusical result.
I am happy with these speakers as they are. From a source first POV you can improve so much upstream to the speakers.

Edit: I tried felt strips on the area where the plastic speaker cable connector board is mounted with eight screws to the body of the speaker and used different torques for the screws. It was a complete disaster, mounting the board directly without any damping was best.

[lejonklou]

What are your thoughts on completely rebuilding the crossover with high-quality components?

My thoughts are these: You will fail miserably.

I tried to improve the filters, certain that it would not be particularly difficult. It was the opposite. Every value is precisely where it should be. Every component, cheap as it may seem, has the perfect characteristics for this speaker. I failed to improve anything except wiring and mounting.

[Masi]

What are your thoughts on completely rebuilding the crossover with high-quality components?

My thoughts are these: You will fail miserably.

I tried to improve the filters, certain that it would not be particularly difficult. It was the opposite. Every value is precisely where it should be. Every component, cheap as it may seem, has the perfect characteristics for this speaker. I failed to improve anything except wiring and mounting.

Thank's for that Feedback. Rebuilding the Crossover with identical but other parts will not be a success.

[Masi]

In the meantime, I have upgraded my amplifier. That was another big step forward. I have had extensive listening sessions with these speakers. I would like to make one more point here: As Fredrik Lejonklou has pointed out, these speakers have a "realness" that makes you feel as though you're listening to the music directly instead of to a loudspeaker that is trying to push air. You have the feeling that you are inside the music, or that you are listening to the recording directly (in the studio / concert hall). For me, this had the effect that I changed the music very often. Because in the past I had always looked for the typical hi-fi attributes such as deep, contoured bass, clear highs, homogeneity, three-dimensionality, presentation, spatiality etc. in recordings or when listening. In this context, I always looked for the best mixed recordings (the most high-end sound) and I never listened to worse recordings to the end. Maybe someone can relate to this realization. Now that I have the JBL 3677, where I am "freed" from all these attributes and they no longer play a role, I am much more on the lookout for albums and songs that I like musically. In other words, I'm no longer worried about finding the best recordings, but rather about discovering new music that I like!

[Masi]

Of course, I also measured the frequency response of the speakers in my living room. There were some major peaks above 80hz, which I was able to filter out with my RME using DSP. This gave the loudspeaker more authority and contour in the bass. I knew that the JBL 3677s have a drop of -10db from 10khz to the very top, approx. 18khz. This is the famous THX curve (if I remember correctly). So you can get the feeling that a little more "steam" at the top might be good for some recordings. I was able to correct the frequency response of the speakers with the RME accordingly. Now I had "corrected" this falling frequency curve. I'm not sure if that's better. I think it changes the typical sound of the 3677 to the detriment of a new speaker with a new frequency response, so to speak.

Although I love the JBL 3677, I wondered if a JBL S4700, K2 (all three-way) or a 4367 (two-way) (all over 10'000 EURO) would sound better. Secretly, of course, I tried to defend the JBL 3677 as the ultimate speaker, but I haven't heard the others and presumably they will do a little better (objectively speaking).
Then I came up with the idea of a "super tweeter". I looked around at Mudorf and decided on an AMT that radiates the sound both forwards and backwards.

[Masi]

I connected the AMT with a simple crossover at the connection point. I don't want to say that I have a completely new speaker, because I don't (because the frequency response was not bent, as in my experiments with the Push over 10khz using an RME preamp, which took away the identity of the JBL. No, what I heard was simply a certain airiness and lightness "upwards". In addition, the spatiality of the JBL 3677, which was not particularly good, was raised to a new level thanks to the rear-firing ATM. Now I finally have a speaker that I can listen to with satisfaction and don't have to think that something is missing. Even the slightly noticeable over-boosting in the mid-range on certain recordings was now "compensated" in a way by the supertweeter and the greater energy in the treble, or at least it no longer had a negative effect. If you have the means, I would definitely advise you to try out this "mod" before considering other speakers.

[Masi]

Below: JBL 3677 with Mundorf AMT Supertweeter.

[springwood64]

What a cool experiment.

How did you arrive at the position of the super tweeter? Does it make a difference if you move it forward or backward?