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Sequel II Bass Problems

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Hi,
New to the Forum and enthusiast of the ML sound. I'd appreciate if someone could help me out with a problem:

Just bought a pair of Sequel IIs, listened to them where I bought them, everything worked great, bass response good. Transported them home in my car (500 carefully driven kms), set them up, the sound of the panels is great after positioning them right, but - no sound from the bass speakers on both speakers at all.
Changed cables, checked the Bi-amp bridging plates, used three different amplifiers from 80 W to 290 W - no change. I opened the box to see if cables had fallen off - could not see anything suspicious. Wiggled the connectors, checked for loose terminals, everything okay. There is a switch that is set to "off" in both boxes, so I left it (did not change anything when I put it to "on").
Is there an LED on the Sequels just like on the bottom of the Aerius to indicate operation?
Electrics / electronics is no prolems for me but before attacking any major operation on the inside of the box I thought I'll ask here.

I am puzzled that the basses on both speakers do not work, meaning when you put your ear close to them, no sound, hiss or crackling whatsoever, even when you put on Bach's Toccata in D - and that organ produces bass!

Comments are much appreciated. The Sequels are in my home in the North of The Netherlands, not really close to a ML dealer or service station!
 

JonFo

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Man, that's a bummer. New speakers and no low freq output. it has to be a connection that came loose somewhere.
The fact that both speakers have the same issue is suspect. I could see one speaker having an issue, but both? This leads one to question cabling or some other upstream issue first. But sounds like you’ve looked at that.
If you are using just one cable to drive the speaker, then it clearly is some connection on or inside the speaker itself. The Bridging straps are the usual suspects, So double and triple check those.

If that is not it, here's what I'd suggest:

Remove the bridging straps and connect the amp straight to the low freq input (bottom) posts.
If you get no sound, then there is an internal connection issue. Unplug the mains, then open the Crossover box and look for wiring going between the low freq posts and the passive crossover elements. There is an inductor, some resistors and some caps in the LF xover. Make sure all joints are solid and that all components are firmly affixed to the board. If a heavy part like the inductor got shaken loose during transport, it could have broken a wire or loosened a solder joint.

Before digging inside the woofer box itself, do check that the cable to the woofer itself is the culprit by very carefully wiring the amp output directly to the line going to the woofer. If that still does not work, then can be fairly sure that one of the terminal connectors to the woofer is loose or the wires going into the woofer are broken. Usually, it will be the connection to the terminals on the woofer.

To check that connections to the woofer are good, you will need to remove the woofer and look at the connections to it inside. This involves removing the rails, removing the lower perforated cover and then using the correct bolt driver, remove the woofer. Prying the driver out may or may not be hard due to the rear basket seal bonding with the wood over time.
Check the connection to the woofer.

Oh, and welcome to the forum!
 
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Sequel II Bass Problem found

An Ohmmeter revealed what the problem was: the Bi-Amp bridge plate between panel and bass inputs shielded (very clever!) the bass inputs from the signal that I had applied on the upper plugs. When I moved the wires from the amp down, the bass speakers came to life (and the panels were dead). These bridging plates should be called "bridge preventer" plates. They just kept the prongs away from the contact points. Easy fix - and what a sound now!

The Sequels play in a 10.5 x 4.75 m (34 by 15 feet) room with a 4.2 m ceiling, floor carpet, lots of high windows on one side (with drapes) and a wall broken by doors and furniture on the other; I moved the Sequels about 3 feet from the rear and 3 feet from the sides for a best transparent sound picture. I never thought sound could so real.
 
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Thanks for the input, Jonathan

Jonathan, you hit the nail on the head. It was the bridge plates. When one looks at them, they look as if they MUST give a contact somehow and somewhere between those posts.
And then I remembered - the gentleman I bought the speakers from had them bi-amped and the bridge plates removed when we listened to them.
Thanks for the input. Makes one happy ML listener more.
Arthur
 

Jeff Zaret

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Arthur,
Welcome. :D

I too have Sequel II's and yes I have seen that problem. What I would do if you are not going to bi-amp/wire these speakers is, get more of your favorite speaker wire. You will not need a lot and make your own bridges/jumpers from that wire. This is what I did and although I could not tell you if it was a huge difference they always work.;)

For your information my Sequel II's are now used as my read speakers in a 5.1 HT setup but when I was using them as fronts they were really great.


Again welcome


Jeff:musicnote:
 
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Sequel bridging

Thank you, Jeff. I did just that and wound an "S" around the posts.
Everything works great. What a sound!

What would the advantage of bi-amping be, and how would one go about it? This question probably falls into the category "basic stuff" but I am curious to hear comments.

All I need now is another set of MLs to create the rear speakers in my quadrophonic setup.

Arthur
 

Jeff Zaret

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Arthur,
I did like bi-amping when I used my Sequel II's as my front speakers. I now have CLSiiZ's as my front speakers and as you know they are not biamp-able. :)

At the time I had my Sequel II's as my fronts the amp I had, Rotel 1090, had two pairs of outputs from the amp itself and I used those to drive the panels and woofer sections. I did not have a separate amp at that time but that would be the optimum because then you can have total control. The panel does not need a lot of power and if you can do it, drive them with a tube amp. The bass/woofers, in my opinion, should be driven by a good SS amp.

The sound, as most here who are doing it will tell you, is more detailed and controlled. If you can borrow an amp or have an extra one try it and listen for a few days and see if you like it. :D

Good Luck


Jeff:musicnote:
 
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