Altec MX5021 Speaker Mod
I have chance to mod the Altec MX5021. I think so far MX5021 is one of good candidate to be modded (though I prefer Altec CS21 or 621/641 series, but they have been discontinued).
The target of this mod should fulfill 3 main criterias:
1. Affordable
2. The components should be easy to find
3. Significant result
It’s quite challenging for me, since you know that I don’t (never) expect much from a multimedia based computer (some of them are good, but not good enough for my taste). Anyway, since this is just for fun, so let’s do it.
Here’s the Altec MX5021 system:
This system has a little bit bright sound, metallic, a little bit harsh, not too detail for music, and average mid. I think the subwoofer is for movie (THX Certified) than music. Need to be improved a little bit in the low bass region. I think it’s good enough for most people, but not for me 
The internal crossover uses “bad” non-polar eletrolytic. Also you can find small inductor with ferrite. This is bad. Very bad. They use 1st order for high pass section, F3 at around 8 kHz I think (if I calculate them correctly). The two mid woofer is not working on same region. I think they build a bandpass filter and both woofer works in different region. Need to fire up my simulator to check the actual graphs, but since I think this is just for fun, I don’t sweat a lot 
The components are: 4.7 uF, 6.8 uF, 47 uF, 0.8 mH, and 0.25 mH.
Below is just another view of the stock crossover.
I removed all the “tiny-little-cute” capacitor from the board. Made by Samxon. A well known brand for Capacitor in China, I guess. I’ve seen a lot of electronic consumer product use this brand.
All of the capacitor were upgraded. I used better capacitor for the high pass filter (the black tube). And for the mid-woofer application, I chose the lower grade (yellow tube) than the one used for the high pass filter. Because this is non-elco based capacitor, so you can see the giant size of the new capacitor. Well, I don’t have enough space there. Sorry for bad layout
I’ll do more mods within next few days. I’ve order a special inductor and hope they can make it in small size so I can fit them inside. The cable also will be upgraded to a better one. Especialy the signal cable inside the crossover.
The result so far:
The high extension is absolutely better. I can hear more detail, even from music like Siti Nurhaliza (Cinta Tak Berganti), to Kari Bremens (A Lover in Berlin) and Rim Banna (The Mirror of My Soul). Even my friend (not an audiophile) can hear the different! The mid woofer have not reached my satisfactory level. Cable and capacitor size should be checked again. Will do soon. It’s clear enough that I need a new inductor to fix the mid-woofer. Just hope the ordered inductor can be fitted inside (though it’s crowded enough) or otherwise I need to find a better placement.
The subwoofer also need a little fix. But it should be on my last priority.
Read more:
http://jimmyauw.com/?p=120
December 17th, 2006 at 10:28 am
wew broo… cool abiss… CS21 gua gimana nihhh
mau mod tapi gak ada skill dan knowledgenya 
December 29th, 2006 at 10:58 am
Wow.. mr.. Jimmy u r such a Exellent Craftsman…. Kalo bolehh bantuin wa mod MX gwa juga donk…pretty please…
coz im totally amateur in Electrical Device& component:(
January 4th, 2007 at 11:20 pm
wow, that was quite an awesome mod.
maybe you can help me and jozzy do a little works on our speakers?
March 15th, 2007 at 11:54 am
[...] If you haven’t read my previous article, please click here. I discussed the mod of MX5021’s satellites. Now, it’s time for the electronic parts I opened the Altec MX5021 subwoofer yesterday. Here’s the picture of the board inside. We can see two big rectifier, some big capacitors (removed from the board), and some op-amps (all are ST4558C). [...]
April 19th, 2007 at 12:06 pm
Bro Jimmy, saya punya MX 5021 + SC Audigy2 kalau mau ningkatin kualitas suaranya secara software (driver + player) pake apa? Oya, kalo tetang Mod MX 5021 ini sptnya teknis banget ya… dan saya juga binggung mau beli kapasitor buat upgrade nya dimana? dan bisa ga dikerjain sama teknisi service an audio, krn saya ga ngerti tuh elektronika takutnya malah rusak kalo upgrade sendiri, mohon bantuannya bro jimmy, thx
October 7th, 2007 at 1:46 am
[...] there was just one Jimmy Auw in Indonesia or someplace who had done the mods. That webpage is here: Jimmy’s Junkyard Blog Archive Altec MX5021 Speaker Mod I don’t agree with all of Jimmy’s mods, and down in the comments section are what I ended up [...]
November 20th, 2007 at 7:12 pm
What are those huge capacitors made of? Polypropylene?
January 16th, 2008 at 12:34 am
Jim,
pls tell me the replacement components’ voltage and the uf…
January 16th, 2008 at 3:39 pm
Same value as original.
Thank you.
January 16th, 2008 at 5:13 pm
bro.. dari forum banyak anak2 tuh pingin modifikasi Altec Lansing MX5021, termasuk gw bro.. gimana kalau kita upgrade bareng2… gw yakin semua pasti pada mau.. tar saya yg atur soal pertemuan. tar bung Jimmy tinggak datang dan hasil apa yg kita kerjain bisa kita masukin ke forum sebagai bahan diskusi. dimana dengan speaker yg sudah ada kita tingkatkan kualitasnya.. tapi, bung Jimmy sibuk sih.. and gw ngerti lah…
January 16th, 2008 at 6:13 pm
Memang ada rencana ketemu di mana bro? Dari saya pribadi agak susah dari sisi komponen karena komponen rata2 stok lama saya…. barang baru gak tau ada atau tidak… kalo memang ada, rasanya saya bisa bantu untuk sekedar kasih panduan (jikalau memang pas waktunya cocok dan saya tidak janji)…
Coba kontak dengan bro Pemula_Kompie juga di CHIP Forum… dia juga suka mod…
Thanks.
January 17th, 2008 at 9:49 pm
Thanks for fast reply
I had opened the satelite last night, but it’s a cut-cost product from AL, darn… (pls refer to the link below)
Just got 1 cap on the board, 50v 15uf for tweeter.
should i replace it with a bypass cap?
http://img33.picoodle.com/img/img33/4/1/15/skydriver/f_q03m_4e1a216.jpg
January 18th, 2008 at 9:18 am
Replace it with better caps first if you can… changing XO design is not recommended unless you know what you are doing…
January 19th, 2008 at 5:45 pm
done.
Replaced the 50v 4.7uf with 100v 4.7uf bypass cap and changed the cable too (inside the satelite)…
anyway, cant found 100v 15uf cap to replace the 50v 15uf and i just leave it =.=”
thanks!
April 10th, 2008 at 5:41 pm
setelah dari article mod subwoofer
koq modifikasi satelit kayanya beda sekali dengan subwoofer
1. komponen2 kuning dan hitam itu apa tergolong kapasitor?mereknya? soalnya bentuknya beda
2. tinggal ganti dengan komponen yang value-nya sama yha?
3. kabel2 yang warna warni itu perlu diganti juga? klo iya ada saran untuk jenis kabel yang harus dipakai?
April 25th, 2008 at 11:12 am
hi there jimmy,
i’ve open up my speaker and its nothing like ur crossover cct, urs are 3-way crossover cct but mine only 2-way crossover cct. i think my spk was one of the cut cost version (sad) anyway can u send me the crossover cct 4 ur speaker, i would like to change the crosover of my spker to see da diffrence, thnx.
April 27th, 2008 at 7:55 pm
You can’t use different crossover design. Most likely, Altec has changed the drivers for your speaker, so they came up with new crossover.
Better stick with the one that you have.
Thank you.
April 29th, 2008 at 7:05 pm
i just want to try out how different the sound would be with 3-way crossover, i notice that they are stil using the same speaker but only change the crossover design to 2-way to save the build cost on the components used . i dont know what they did have an effect on the THX certification. maybe this can help afew out there whose not satisfied with the newer model sounds.
May 10th, 2008 at 11:09 am
Bang Jim, aku udah putus asa nih nyari MX 5021, kalau udah bosan boleh dong kita beli bang, posisi kita di medan, gimana kira2 bang?
May 11th, 2008 at 5:38 am
@Yance cari speaker seri lain aja bwt di modif…. kan lebih asyik …rencana mau coba modif ACS 45.1
(white n black series) … blm ada wktu nh…pgn bgt…
June 28th, 2008 at 3:42 am
Please help me with the modding of this AMP http://my-cool-gsm.hit.bg/DSC00097.JPG
I wont to clear the sound.PLEASE HELP ME!!!
Sorry for my bad English.
July 8th, 2008 at 5:04 pm
Hi Jimmy,
Nice article!
> Jimmy Auw Says: April 27th, 2008 at 7:55 pm
> You can’t use different crossover design. Most likely, Altec has changed the drivers for your
> speaker, so they came up with new crossover.
> Better stick with the one that you have.
From what I can see on your photos and on this one http://img33.picoodle.com/img/img33/4/1/15/skydriver/f_q03m_4e1a216.jpg , I would say they are still the same 4-ohm drivers, according to type numbers. I think the “performance optimization” process took place here making the product cheaper to build with “quality still acceptable for consumer”.
Could you, please, post a photo of the back side of satellite crossover PCB (if not the schematics)? At least it would be interesting to see what Altec’s engineers came with prior to the marketing department intervence
Regards,
JT
July 8th, 2008 at 6:14 pm
Hi,
I dont have the speaker on hand now.
Please be noted that same 4 Ohm speaker doesnt mean it’s the same one. We are not talking about impedance only, but also the T/S parameter. Different T/S parameters need different crossover design. We cant make sure they are the same or not unless we do the measurement for T/S parameters.
Thank you.
August 5th, 2008 at 9:36 pm
can you help me how to mod my altec 5021.