Hi all!
My first post here!
So I have an Aiwa NSX F958 with a dysfunctional main unit, likely 25 years old, and left unused for last 10 years. Rats had their fun. Today I took it out to a local shop and got the stuff back in a usable condition, and now I need a matching amplifier to drive the system from a 3.5mm audio jack (output from my TV).
Speaker : 6 ohm, 40 W RMS
Subwoofer : 6 ohm, 170 W RMS
( RMS spec is what I remember reading from its catalogue 7 years back, I hope its right)
I have two cabinets, each with one speaker and one subwoofer. Can we call it a 2.2 speaker system? (I usually hear just 5.1 these days). Please see attachment for a pic.
I inquired in some local shops here. All of them have car audio amps that are like 4 channel 45 W output, with no separate subwoofer output. The ones with sub out are only the 5.1 amps. Didn't find any stereo amps with sub out.
I dont want to buy two 5.1 amps for driving my two subs! What are my options !?
My first post here!
So I have an Aiwa NSX F958 with a dysfunctional main unit, likely 25 years old, and left unused for last 10 years. Rats had their fun. Today I took it out to a local shop and got the stuff back in a usable condition, and now I need a matching amplifier to drive the system from a 3.5mm audio jack (output from my TV).
Speaker : 6 ohm, 40 W RMS
Subwoofer : 6 ohm, 170 W RMS
( RMS spec is what I remember reading from its catalogue 7 years back, I hope its right)
I have two cabinets, each with one speaker and one subwoofer. Can we call it a 2.2 speaker system? (I usually hear just 5.1 these days). Please see attachment for a pic.
I inquired in some local shops here. All of them have car audio amps that are like 4 channel 45 W output, with no separate subwoofer output. The ones with sub out are only the 5.1 amps. Didn't find any stereo amps with sub out.
I dont want to buy two 5.1 amps for driving my two subs! What are my options !?
Attachments
In schematic diagram 3 of the service manual, there are 47uF caps located at the output of Left and Right channel power amplifiers that connect to "surround" speaker drivers. There are also separate connections and leads to "Tweeter" speaker drivers, both in the same box I assume, from the pic. The surround effect looks suspiciously like an old Hafler-Dynaco style quad adaptor and is switched with a relay. I'm not sure why this was done - perhaps cheaper to construct or it allowed another model/speaker system to be easily adapted. I have seen versions wired to 4 small boxes and a sub - perhaps that's what is meant.
I don't think you'll be able to use these speakers boxes as they are because they probably don't have a crossover matched to the driver sensitivities, nor will you hear reasonable bass.
I don't think you'll be able to use these speakers boxes as they are because they probably don't have a crossover matched to the driver sensitivities, nor will you hear reasonable bass.
I'm really sorry for the late response. I'm guessing I wasnt notified of any responses! Thanks a bunch to all of you for the detailed responses! Let me go through them one by one!
Could you please elaborate on "Crossover matched to the driver sensitivities" ? I would like to learn more, to understand it. Would you please recommend some readings where I can understand about the important jargons in audio?
There are two connections. One for the subwoofer and another for the speaker + "super" tweeter as they call it.
Could you please elaborate on "Crossover matched to the driver sensitivities" ? I would like to learn more, to understand it. Would you please recommend some readings where I can understand about the important jargons in audio?
There are two connections. One for the subwoofer and another for the speaker + "super" tweeter as they call it.
I think he is talking about the 47uF capacitor on the speaker output of the amplifier.
Assuming there are not any other crossover parts in the speaker, and if this capacitor is in line with the positive speaker terminal of the 6 ohm tweeter, then we can guess it is a 1st order buttworth filter at 565Hz.
In laymen terms, it means that the 47uF capacitor protects the tweeter from burning out from too much bass. It rolls off at 6dB per octave, so at 282.5 Hz will be -12 dB, and another octave lower (which is cutting the frequency in half again) will be -18 dB at 141.25 Hz, -24 dB at about 70 Hz, -30dB at 35 Hz and so on. -Trying to play 35Hz through the tweeter at full volume would be very bad, so reducing the volume by 30dB at that frequency keeps the tweeter cool and happy.
Just remember if you use a different amplifier to add that capacitor to the speaker.
Never mind, he said 47uF on surround output of Amp. I may be confused which connections are where, and which speakers are what. 565hz seems kinda low for a tweeter crossover too, more likely that's for a mid driver (i.e. surround speaker)
At least now you know how a butterworth filter works now.
Assuming there are not any other crossover parts in the speaker, and if this capacitor is in line with the positive speaker terminal of the 6 ohm tweeter, then we can guess it is a 1st order buttworth filter at 565Hz.
In laymen terms, it means that the 47uF capacitor protects the tweeter from burning out from too much bass. It rolls off at 6dB per octave, so at 282.5 Hz will be -12 dB, and another octave lower (which is cutting the frequency in half again) will be -18 dB at 141.25 Hz, -24 dB at about 70 Hz, -30dB at 35 Hz and so on. -Trying to play 35Hz through the tweeter at full volume would be very bad, so reducing the volume by 30dB at that frequency keeps the tweeter cool and happy.
Just remember if you use a different amplifier to add that capacitor to the speaker.
Never mind, he said 47uF on surround output of Amp. I may be confused which connections are where, and which speakers are what. 565hz seems kinda low for a tweeter crossover too, more likely that's for a mid driver (i.e. surround speaker)
At least now you know how a butterworth filter works now.
I had forgotten this thread but jayaura has just reminded me.
The speaker boxes on the 958 model at least, are 4-way but the "sub"woofer inside, is connected independently via a second set of connectors (I assume they are RCA type plugs by the assembly drawing). As mentioned earlier, it appears that the remaining 3 speakers, called "tweeter" collectively, are connected similarly but via a 47uF capacitor. Presumably, it's a bipolar type, as used in many speaker crossover networks. There is likely another simple capacitor filter network inside the speaker box to divide the output between the 3 smaller speakers with minimum losses.
The "sub"woofers are specified as 200 mm drivers, mounted inside the ported box and the "tweeter" section actually comprises a mid-bass driver 120mm, upper-mid 80mm and tweeter 20mm. Apparently, there is some licensed, multi-voice sound processing network in there but I don't see it at the power amplifier stage, just in the signal processing chips, like the Dolby noise reduction system for tapes.
A similar 959 model actually has 4 separate speaker boxes, so this could be what the surround sound comments refer to, but when compared to pics on the web,the descriptions seem confused so I'm not really certain though I've seen countless numbers of these and very similar products wind up in pieces at recycler's yards.
To use these speakers, you will need to have the subwoofers connected to get any useful bass at all. You could simply connect the subwoofer section directly and couple the "tweeter" section in parallel, with the the addition of a new (try that same 47uF) bipolar capacitor in series with the + lead. Don't omit it or you'll likely damage the smaller drivers. If the sensitivity of the bass and "tweeter" speaker sections match, you may find this is OK without further changes. However, I would check and compare with different types of music and another high quality stereo system as to whether the bass it correctly matched to the midrange frequencies. The difference with well matched speaker drivers can be dramatic
The speaker boxes on the 958 model at least, are 4-way but the "sub"woofer inside, is connected independently via a second set of connectors (I assume they are RCA type plugs by the assembly drawing). As mentioned earlier, it appears that the remaining 3 speakers, called "tweeter" collectively, are connected similarly but via a 47uF capacitor. Presumably, it's a bipolar type, as used in many speaker crossover networks. There is likely another simple capacitor filter network inside the speaker box to divide the output between the 3 smaller speakers with minimum losses.
The "sub"woofers are specified as 200 mm drivers, mounted inside the ported box and the "tweeter" section actually comprises a mid-bass driver 120mm, upper-mid 80mm and tweeter 20mm. Apparently, there is some licensed, multi-voice sound processing network in there but I don't see it at the power amplifier stage, just in the signal processing chips, like the Dolby noise reduction system for tapes.
A similar 959 model actually has 4 separate speaker boxes, so this could be what the surround sound comments refer to, but when compared to pics on the web,the descriptions seem confused so I'm not really certain though I've seen countless numbers of these and very similar products wind up in pieces at recycler's yards.
To use these speakers, you will need to have the subwoofers connected to get any useful bass at all. You could simply connect the subwoofer section directly and couple the "tweeter" section in parallel, with the the addition of a new (try that same 47uF) bipolar capacitor in series with the + lead. Don't omit it or you'll likely damage the smaller drivers. If the sensitivity of the bass and "tweeter" speaker sections match, you may find this is OK without further changes. However, I would check and compare with different types of music and another high quality stereo system as to whether the bass it correctly matched to the midrange frequencies. The difference with well matched speaker drivers can be dramatic
Thank you very much for responding!
I will most likely need to make an amp for myself, which is why I was stalling it since I posted. I will make an analog amp that will take input from headphone jack. With that, I will have the freedom of tuning the specs as much as I can. I'm looking at circuits based on LM3886 and TDA7294 which was suggested by MAAC0 and Veysel
Looking at the specs on page 6 in the service manual you linked, I see two specs for the Low Freq amp: Rated (130W) and Reference (170W). What is the difference with those values? If I'm looking for selecting and appropriate chip, which value should I be considering ?
It has Dolby and "BBE". Must be something Welcome to BBE Sound made.
To use these speakers, you will need to have the subwoofers connected to get any useful bass at all. You could simply connect the subwoofer section directly and couple the "tweeter" section in parallel, with the the addition of a new (try that same 47uF) bipolar capacitor in series with the + lead. Don't omit it or you'll likely damage the smaller drivers. If the sensitivity of the bass and "tweeter" speaker sections match, you may find this is OK without further changes. However, I would check and compare with different types of music and another high quality stereo system as to whether the bass it correctly matched to the midrange frequencies. The difference with well matched speaker drivers can be dramatic
I will most likely need to make an amp for myself, which is why I was stalling it since I posted. I will make an analog amp that will take input from headphone jack. With that, I will have the freedom of tuning the specs as much as I can. I'm looking at circuits based on LM3886 and TDA7294 which was suggested by MAAC0 and Veysel
Looking at the specs on page 6 in the service manual you linked, I see two specs for the Low Freq amp: Rated (130W) and Reference (170W). What is the difference with those values? If I'm looking for selecting and appropriate chip, which value should I be considering ?
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