Old speakers upgrade

AK3

Member
2016-01-21 12:29 am
Hi,
I just got really old speakers Technics SB -k22.
I'm thinking of using it's cabinet and possibly woofers and replace mid-range drivers as well as tweeters. I'm not sure about crossover.
Google showed me that
mids are 5" 8 Ohm EAS 10PM169S;
tweeters are 4" 8 Ohm EAS 65PH433/86BT
woofers are 8" 8 Ohm EAS 20PL1598A

What will be your advice for replacement?
Thanks,
AK3
 
I'm not sure about crossover

Hi,
you should check it, as it defines the power that flows through the speakers.
I cannot tell you to change the tweeter if I don't know what kind of filter is placed before; also the original tweeter may be conceived in such a way that it works well with the original filter.

Nowadays I see that a 3 way design uses the woofers in their pistonic range and so the midrange speaker has to cover an octave more than in the past.
This design lowers the sensistivity of the speaker ( I guess ).
 

eriksquires

Member
2013-05-10 4:11 pm
Hi,
I just got really old speakers Technics SB -k22.
I'm thinking of using it's cabinet and possibly woofers and replace mid-range drivers as well as tweeters. I'm not sure about crossover.
Google showed me that
mids are 5" 8 Ohm EAS 10PM169S;
tweeters are 4" 8 Ohm EAS 65PH433/86BT
woofers are 8" 8 Ohm EAS 20PL1598A

What will be your advice for replacement?
Thanks,
AK3

Hi AK3!

Welcome. You sure you don't want to start your own speaker project? The challenge with a project like this is that you end up being turned into a slave of the cabinet. Better off to think about doing your own 2 way project. Maybe from a kit, or maybe doing a lot of learning to pick your own parts.

You can't just go throwing new parts in without understanding a bit about crossover design to begin with, and if you are going to learn that, you probably are going to want to pick your own parts and a cabinet, in that order.



Best,


Erik
 

AK3

Member
2016-01-21 12:29 am
Thank you guys,
Yes, I understand that it is better to start with a scratch my own speaker project to express my creativity and my knowledge. The problem is there is nothing to express. I highly doubt that my handmake cabinet will be better either.
I think with my current knowledge and experience it would be better to start with choosing new tweeter and midrange drivers and maybe replacing crossover.

How I can check crossover? Do I need an oscilloscope or something expensive? Maybe it will be better just replace it with a new one that's fit new drivers?
I couldn't hear any sound from midrange and tweeter and I'm not sure if it is crossover of drivers itself.

There are tons of different types of drivers and I thought that here I can get advice what set of tweeter and midrange will be better.

I could start with 2-ways but would like to keep old cabinet (about 2 cubic feet volume) and woofer 8 Ohms, 100 Watts RMS EAS 20PL159SA.

My receiver can do 100 Watts per channel @8 Ohms load.

Thanks,
 
Definitively too much, 100 W must blow everything in sight, except the woofer.
The woofer has to be removed then you'll have acces to the crossover board , if any.
With a multimeter/tester you check for the "continuity" of the voice coil, so you are sure it's not the speaker ( broken).
As Tom said, check the capacitors ( no, he said to change them ! )

For the "acoustic" matter, a 8" woofer has some difficulties to get past 2 kHz, and a tweeter to match it either; perhaps a waveguide might be useful to tame with the change of directivity at crossover frequency, and a big one is needed for such duty ( about the same size, eight inches ).
 

AK3

Member
2016-01-21 12:29 am
Thanks,
I will check speakers by multimeter/tester for the "continuity" of the voice coil.
Do I just need to measure resistance of speaker or connect it directly to sound output?

Do you guy have any experience with these tweeters?

1. Goldwood Sound GT525.
2000 - 20,000 Hz Frequency Range
100 Watts RMS and 200 Watts Max
92dB
200 Watt 8 Ohm New Silk Dome 92db Tweeter 4 Inch GT525 - Newegg.com
2. PYRAMID
1" 300 Watts Peak Power Heavy Duty Titanium Super Tweeter
Peak Power 300 Watts
RMS Power 150 Watts
Sensitivity 104dB
Frequency Response 2 kHz - 20 kHz
Impedance 4-8 Ohm

PYRAMID 1" 300 Watts Peak Power Heavy Duty Titanium Super Tweeter - Newegg.com
 

eriksquires

Member
2013-05-10 4:11 pm
Thank you guys,
Yes, I understand that it is better to start with a scratch my own speaker project to express my creativity and my knowledge. The problem is there is nothing to express. I highly doubt that my handmake cabinet will be better either.
I think with my current knowledge and experience it would be better to start with choosing new tweeter and midrange drivers and maybe replacing crossover.

How I can check crossover? Do I need an oscilloscope or something expensive? Maybe it will be better just replace it with a new one that's fit new drivers?
I couldn't hear any sound from midrange and tweeter and I'm not sure if it is crossover of drivers itself.

There are tons of different types of drivers and I thought that here I can get advice what set of tweeter and midrange will be better.

I could start with 2-ways but would like to keep old cabinet (about 2 cubic feet volume) and woofer 8 Ohms, 100 Watts RMS EAS 20PL159SA.

My receiver can do 100 Watts per channel @8 Ohms load.

Thanks,

HI there!

Your approach is not uncommon at all, but from where I see you going, learning about drivers and crossovers, measuring, etc. I see you spending a lot of money on this cabinet, then when you've finished wishing you'd started something else but it IS a very good learning experience.

An alternative I'm suggesting is to build a new two kit as a place to start. Here is one of many examples. Instead of trying to upgrade the Technics, build this kit, or something similar then come back and let's talk about analyzing it, and modifying it. I think you may spend less and be much happier with the finished results, and is the same if not better learning experience. One of the cool things about this kit is that using Dayton drivers, you can download all the data files for really great simulations right off their site. This will let you learn about crossover design with XSim (Free tool from Bill Waslo) without having to invest in measurement tools yet. So it's a really great learning lab for you.

There's lot of kits around at all price points. That kit is around $180 for the pair, but you can go far up. As for a cabinet, like I said, you can buy pretty decent but not spectacular cabinets by Dayton from Parts Express.

Of course, there's lots of smart people on this site, so please take advantage of their kindness and expereince by asking about other ides.

Mark Twain was asked to write a short essay in a week. He replied, and my memory is poor!

Can't write a short essay in a week. Can write a long essay in a week. Short essays take longer
It's kind of like that for you. Starting from scratch for a beginner is going to be easier and faster than attempting to fit drivers around an existing cabinet and woofer. Once you are more experienced, it will be much easier, but you won't want to. It's a conundrum. :)

The advice on better parts is true, but again, I think you'll end up in a different place, so I didnt' suggest film caps like I am famous for recommending. Get the 2 way kit, learn how to simulate it, and then let's talk learning about film caps. :) One other idea, is to learn about how difficult a task you are asking, go find some Dayton drivers you think would work in your cabinet, they ahve the FRD and ZMA files you'll need. Plug into XSim and see if you have the moxy yet for crossover design, because that's what you'll need to do if you are going to be replacing drivers. I'll be happy to help!

Best,


Erik
 
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Do you guy have any experience with these tweeters?

1. Goldwood Sound GT525.
2000 - 20,000 Hz Frequency Range
100 Watts RMS and 200 Watts Max
92dB

2. PYRAMID
1" 300 Watts Peak Power Heavy Duty Titanium Super Tweeter
Peak Power 300 Watts
RMS Power 150 Watts
Sensitivity 104dB
Frequency Response 2 kHz - 20 kHz
Impedance 4-8 Ohm

Nowadays you can go with a broader frequency range i.e. that extends over the audible range which is 20 kHz.
The Goldwood has a little horn profile, a waveguide, that enhances acoustic output in its lower range, so the 92 dB SPL ( per Watt at 1 meter ) takes that into account. Probably you can go with lower sensitivity ones, say 90 dB.

If you want to try it, you should get some resistors to lower the output, or better, a L-Pad ( constant load ).

The Pyramid has a sensitivity way out of our target, go figure the ultrasonic content I've talked about in the beginning- it simply isn't made for hi-fi.

Just make a comparison between various woofers in the eight inches category
and see what's the average sensibility of the raw driver - after the crossover and into the box it looses some efficiency too.
 

AK3

Member
2016-01-21 12:29 am

AK3

Member
2016-01-21 12:29 am
Yes, actually I found a capacitor in series to tweeter and mid (both connected in parallel).
[IMGDEAD]http://1drv.ms/1OLaSsq[/IMGDEAD]
[IMGDEAD]http://1drv.ms/1OLaXMK[/IMGDEAD]

Still this needs to be replaced with a crossover.
I'm thinking about two options:
1. Keep current woofer and 3-way design (about 60 Watts): add 3-way crossover, tweeter , and mid
2. Over 100 Watt 2-way 5 kHz or 3 kHz crossover, tweeter, and substitute woofer with wide-range woofer