Help: replacing woofer unit for Sequel II

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coolposter

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Hello gurus,

I need to replace one of the faulty woofer unit on my 18 years old Sequel II.

Question:

1, How can I remove the woofer unit? I removed the panel, front screws on woofer, cable to boards and yet found nothing else to actually remove the woofer itself.

2, What will be a good alternative woofer unit for my Sequel II? I asked Jim @ ML but he didn't recommend the stock one.

Quote: "We have a replacement woofer available but frankly I wouldn’t recommend replacing yours unless they are blown. The newer woofers are $... each and they may not be any better than what you have."

Thanks for your help!
 
"Blown" is usually a cover-all-bases term for any physical woofer damage from excess heat, moisture, separated glue or varnish, etc., be it to spider, cone, surround, voice coil, or magnet.

What it actually "faulty" about yours? If it's anything due to old age, then expect the same to happen to its mate soon (so repair in pairs). I'm guessing foam surround is shot?
 
1, How can I remove the woofer unit? I removed the panel, front screws on woofer, cable to boards and yet found nothing else to actually remove the woofer itself.
They have a slight sealant on the back of the woofer frame. A slight prying will make them come off. I went through the screw hole of the old woofer to pry so I would not possibly damage the surrounding cabinet.

New woofers are 3dB hotter than the original, and last year were running about $140 each. Replace in pairs and not just one.
 
Hum, my recommendation is to stay away from 'subwoofer' type parts, especially ones designed for automotive applications. One note boom is typically the result.

I'd go to DIYaudio.com and ask the folks over there to model the options you have and help you narrow down the best choice.

Looking at what PE has in stock these days, I'd consider the following:

The HiVi D10G

The Dayton RS270 (in shielded or non-shielded versions)

The Arum Cantus AC-250MKII

My personal preference would be for the HiVi, but that Yellow cone might not work for you in terms of WAF. ;)

The DIYAudio guys can recommend any box stuffing changes or minor electrical tweaks (added resistance or capacitance) to 'tune' a driver to this application

I'm going to do this swap in my Sequel II's sometime next year, but I use external X-overs, and can pretty much make anything work.
 
Thanks very much Jonathan!

Arum Cantus AC-250MKII is the only one with matching sensitivity (which is 89db). With HiVi being 88 and Dayton being 90. Does this 1db difference matter?

Also, all 3 woofer units have an 8 ohm impedance but ML uses 4 ohm driver. I guess this part is okay?

Last but not least, I noticed Sequel II has 8 sockets for woofer mounting while these 3 has 12 and 6. Will this be a problem?
 
Also, all 3 woofer units have an 8 ohm impedance but ML uses 4 ohm driver. I guess this part is okay?
No, NOT OK: the cross-over depends on the woofer being nominally 4 Ohms.

Also, that Peerless 830842 XXLS is not going to be happy in a sealed box (as well as the sensitivity possibly being too low: 2.83V into 4 Ohms is 2W).

What is actually wrong with your woofers? I wish I could offer you the original VIFAs from my SL3's, but I'm not quite ready with my active XO yet...
 
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This is the specification from ML
10" woofer - stamped frame

SD = 330cm squared = 0.033m squared

4 ohm driver - Re = 3.77ohms

Fs 20-21Hz

Vas - 98Liter = 3.4cubic feet

Mms - 91gram

BL - 11 Newton/Amp

Sensitivity = 88.8 dB SPL at 1 meter with 2.8VAC input

Efficiency = 85.8 db /1m 1W (1W at 4 ohm is 2VAC)

Qms = 10

Qes = 0.372

Qts = 0.358



I have replace the woofers to Peerless 830842: Type: XXLS 269 SWR 51 147 NWP ALP 4L 4 ohm and they work very good.
 
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I have replace the woofers to Peerless 830842: Type: XXLS 269 SWR 51 147 NWP ALP 4L 4 ohm and they work very good.

Do they really do OK on mid-bass?

The sequel uses a second-order crossover around 250hz, which means the woofer is still are putting out a good bit of info at 500Hz. That XXLS model is subwoofer driver with much higher mass than the factory unit. The freq/ response droops at 500 and I'd not be surprised had pretty high Thd at the point as well.
 
I just had mine rebuilt at a local Audio store and they preform perfect now have you considered getting the stock units rebuilt? just a thought
 
I have replace the woofers to Peerless 830842: Type: XXLS 269 SWR 51 147 NWP ALP 4L 4 ohm and they work very good.
Too bad this woofer is not an ideal replacement because it's on sale at Madisound for $110! The Qts is 0.19 which is not suited for a non-EQ'd sealed cabinet. This woofer is meant for small bass reflex and passive radiator boxes. Try the parameters for it on the Linear Team online calculator to see the simulated response: It's ~6dB down at 55Hz. (SL3 cabinet volume is ~40 liters, and I think the "SL2" is quite close?) Actually that might be pretty useful if one always had a sub woofer....
 
Although this seems wrong, the end result is very good.I Have a sound addition to the mid between 300-500 Hz
 

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