Hi everyone! This is my first thread in the forum. I am very happy to start a new part of my audio life. First repairing, and maybe one day building speakers.
You will quickly realise that I'm a newbie. The situation is the following: I got a 70's combo turntable, which sounded horrible. Thinking it was the reason, I exchanged it with a 80's Technics SL-DD33. It sounds way better! BUT... Now, because I have Sony STR GX-311 receiver which actually works, I realised that there's a problem with one of my loudspeakers. As the title says, the speakers are a couple of two-way Pioneer CS E320.
The problem I heard is that the right speaker sounded muffled, not as bright as the left one. When I changed the routing, I realised that's is not the receivers amp problem, but the speakers. Then I though "Muffled.. Not as bright.. It must be the tweeter.." So I ordered two Dynavox DX159 Tweeters. Today they arrived, and to my surprise, they didn't fit in the wholes (great..), and when I plugged them in, the muffled sound was still there! (great again..).
Now I think this is the project that I needed to finally learn how the whole signal flow from a speaker works, and be able to make some minor repairs. It seems to be a simple enough project to start with.
My questions are:
What would be a first approach to troubleshooting the speaker? I'm planning on making measurements with test tones. I will upload my results in the next days.
Is there a possibility that the muffled sound is caused by the crossover components?
I see that in the crossover there is a TOWA 63v 7uF capacitor, and there's what I believe 2 inductor coils (1.5 mh, and 0.26 mh??). Do this components age? And differently one amp from the other?
Can someone point me in the direction to a thread explaining how to measure drivers and with which software? Maybe the woofer is also working weirdly? It is a 20-716F .
Thank you in advanced.
You will quickly realise that I'm a newbie. The situation is the following: I got a 70's combo turntable, which sounded horrible. Thinking it was the reason, I exchanged it with a 80's Technics SL-DD33. It sounds way better! BUT... Now, because I have Sony STR GX-311 receiver which actually works, I realised that there's a problem with one of my loudspeakers. As the title says, the speakers are a couple of two-way Pioneer CS E320.
The problem I heard is that the right speaker sounded muffled, not as bright as the left one. When I changed the routing, I realised that's is not the receivers amp problem, but the speakers. Then I though "Muffled.. Not as bright.. It must be the tweeter.." So I ordered two Dynavox DX159 Tweeters. Today they arrived, and to my surprise, they didn't fit in the wholes (great..), and when I plugged them in, the muffled sound was still there! (great again..).
Now I think this is the project that I needed to finally learn how the whole signal flow from a speaker works, and be able to make some minor repairs. It seems to be a simple enough project to start with.
My questions are:
What would be a first approach to troubleshooting the speaker? I'm planning on making measurements with test tones. I will upload my results in the next days.
Is there a possibility that the muffled sound is caused by the crossover components?
I see that in the crossover there is a TOWA 63v 7uF capacitor, and there's what I believe 2 inductor coils (1.5 mh, and 0.26 mh??). Do this components age? And differently one amp from the other?
Can someone point me in the direction to a thread explaining how to measure drivers and with which software? Maybe the woofer is also working weirdly? It is a 20-716F .
Thank you in advanced.
Does the muffled speaker have any sound coming from the tweeter (disconnect it to be sure)? The capacitor is in a position to potentially have something to do with it.
Almost certainly it's the capacitor, so replace it with a same value bipolar.
Might want to do both speakers at the same time.
Might want to do both speakers at the same time.
I would measure the speakers with the multimeter, just to be sure they are not open (they should measure around 6 to 8 ohms), then with a bipolar capacitor (4 to 6uF) in series with the tweeter to test them with the amp output and compare both speakers output. Measure the coils too, just to be sure they are not open.
"making measurements with test tones" , yes, that can point you to check if the installed capacitor is bad. If you end up replacing the capacitor on the muffled speaker, consider replacing the other speaker capacitor too.
"making measurements with test tones" , yes, that can point you to check if the installed capacitor is bad. If you end up replacing the capacitor on the muffled speaker, consider replacing the other speaker capacitor too.
"replace it with a same value bipolar" - 7uf is an odd value, I'd replace both with 6.8uF MKT, which is close enough & won't need replacing in the future.
If you stick with the dynaudio tweeters, you'll also need to pad down the tweeters by 5dB, try an L-pad as calculated here: L pad calculator - attenuation dB damping impedance decibel loudspeaker speaker voltage divider - sengpielaudio Sengpiel Berlin. Measure the DC resistance of the tweeters and use that value for "Speaker Impedance' in the calculator. There will be posts saying 'don't do that', but it'll get you close enough in this case....
If you stick with the dynaudio tweeters, you'll also need to pad down the tweeters by 5dB, try an L-pad as calculated here: L pad calculator - attenuation dB damping impedance decibel loudspeaker speaker voltage divider - sengpielaudio Sengpiel Berlin. Measure the DC resistance of the tweeters and use that value for "Speaker Impedance' in the calculator. There will be posts saying 'don't do that', but it'll get you close enough in this case....
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Thank you all so much! It's so motivating to have so many people from al around the world giving a helping hand to solve this.
I have checked the woofer, and the measurements are between 6 and 8 ohms, as LuigiDJ said. Then, the woofer is not the problem. I will give the capacitor change a chance and update with the results.
The old tweeter is dead. I hope it wasn't me while opening it up. When I opened it, everything seemed connected, without a scratch. But now I checked pluggin it back, or with the multimeter, and it doesn't have any signal whatsoever. I think I will have to stay with the Dynaudio ones if there's no way around it.
PeteMcK
Thank you all!
I have checked the woofer, and the measurements are between 6 and 8 ohms, as LuigiDJ said. Then, the woofer is not the problem. I will give the capacitor change a chance and update with the results.
The old tweeter is dead. I hope it wasn't me while opening it up. When I opened it, everything seemed connected, without a scratch. But now I checked pluggin it back, or with the multimeter, and it doesn't have any signal whatsoever. I think I will have to stay with the Dynaudio ones if there's no way around it.
PeteMcK
Is this because of the type of tweeter?
Thank you all!
It's because the Pioneers have a sensitivity of 86dB, while the Dynaudios are 91dB. With no L pad, the tweeters will be too loud.