4 Ohm tweeters and speakers in 850

[xnRS]

Hey everyone

I replaced aftermarket low quality unit with factory SC-802, but it requires 8 Ohm speakers instead of typical 4 Ohm ones

If door speakers i could easily find at local from guy who disassembles 850, but tweeters... They are mostly died from age, and i have 2 of those in the trunk, but all tweeters for sale are 4 ohm.

Is there any solutions except changing radio unit to aftermarket one ?

[MrAl]

Hey everyone

I replaced aftermarket low quality unit with factory SC-802, but it requires 8 Ohm speakers instead of typical 4 Ohm ones

If door speakers i could easily find at local from guy who disassembles 850, but tweeters... They are mostly died from age, and i have 2 of those in the trunk, but all tweeters for sale are 4 ohm.

Is there any solutions except changing radio unit to aftermarket one ?

Hi,

You could add a series resistance in series with the 4 Ohm speakers with loss of power of one half. The series resistance would be 4 Ohms and it would have to be a power resistor that can take the full power. Going by the full power is better than the real requirement of half the power but a power resistor working at full rated power gets really really hot, which is not a good idea in any application. The resistor should be rated for 2x the required power which means it should be the same power as the 'radio' or whatever powers the speaker normally. The resistor has to be mounted so that it gets free air flow also and mounted so that it does not melt anything or cause a fire of course. Some power resistors come with 'stands' that keep the resistor body off of the chassis and others bolt to the chassis which helps them stay cooler.

You might also put two 4 Ohm speakers in series to make the 8 Ohms. That technically will not lose any power but the sound power distribution will be slightly different, which may not matter at all though. You also have to have a place to mount the additional speaker(s).

The aftermarket question is interesting in itself too. Does anyone make an aftermarket radio/whatever to fit in the same space as the original? I would be interested to hear about one for a 1998 v70.

[foggydogg]

The tweeters in the dash have always been a struggle to replace. Some people put a multi-component speaker in the doors and abandon the separate tweeters.
Many modern replacement tweeters aren't as sensitive to impedance ratings, unless you like playing music loud enough to rattle the windows. Later P80 dash speakers will work, but may need to be modified to fit in the space; I don't remember if the plug is the same.

[xnRS]

Only problem, i want to install them without any major changes to the factory audio system, or make it easily removable, i think there is another solution maybe - HU series radios, HU-1205 for example, they are using 4 ohm speakers, but hu radio requires adaptor from SC connector to HU, i think they are sold somewhere, but sometimes people do them from 2 adaptors - SC radio to universal radio and standard radio to HU, they remove standard radio connectors, and solder those two, maybe i'll do that in future... when i'll find 2 of those adaptors, or get ones from Aliexpress, but, i need something to do with current speakers, and tbh, i don't like the look of HU radio(except HU-1205), so this is current problem for me

[Nikolaech]

SС- 802 designed for speakers with an impedance of 4 ohms. Another thing is their connection in the Volvo 850. The best solution, in my opinion, is component speakers. Used speakers, due to age, definitely cannot be good.

Тоже болит голова за твитеры. SC 802, если посмотреть его характеристики, рассчитан на сопротивление динамиков 4Ом. Другое дело их подключение в Volvo 850. Все тридцати-летние динамики в силу возраста, однозначно не могут быть хорошими, На мой взгляд, компонентные динамики, лучшее решение. Можете смело ставить пару на перед, С задними сложнее или динамики 8Ом или последовательно два динамика на сторону. Если нужно относительное качество то только усилитель, не обязательно на 1000 ватт. Например я поставил 6-канальный с Toyota Windom

[matthew1]

Take a look at this thread viewtopic.php?t=37781

Lots of 850 speaker info with replacement product model numbers...

[MrAl]

Hey everyone

I replaced aftermarket low quality unit with factory SC-802, but it requires 8 Ohm speakers instead of typical 4 Ohm ones

If door speakers i could easily find at local from guy who disassembles 850, but tweeters... They are mostly died from age, and i have 2 of those in the trunk, but all tweeters for sale are 4 ohm.

Is there any solutions except changing radio unit to aftermarket one ?

Hi,

You could add a series resistance in series with the 4 Ohm speakers with loss of power of one half. The series resistance would be 4 Ohms and it would have to be a power resistor that can take the full power. Going by the full power is better than the real requirement of half the power but a power resistor working at full rated power gets really really hot, which is not a good idea in any application. The resistor should be rated for 2x the required power which means it should be the same power as the 'radio' or whatever powers the speaker normally. The resistor has to be mounted so that it gets free air flow also and mounted so that it does not melt anything or cause a fire of course. Some power resistors come with 'stands' that keep the resistor body off of the chassis and others bolt to the chassis which helps them stay cooler.

You might also put two 4 Ohm speakers in series to make the 8 Ohms. That technically will not lose any power but the sound power distribution will be slightly different, which may not matter at all though. You also have to have a place to mount the additional speaker(s).

The aftermarket question is interesting in itself too. Does anyone make an aftermarket radio/whatever to fit in the same space as the original? I would be interested to hear about one for a 1998 v70.

Hello again,

I forgot to mention that if you only have 8 Ohm speakers and you need a 4 Ohm speaker you can wire two 8 Ohm speakers in parallel and that will present a 4 Ohm load the radio/stereo system. If you only have one 8 Ohm speaker and you need 4 Ohms for the radio, then you can also use a high power 8 Ohm resistor in parallel with the 8 Ohm speaker and that will satisfy the radio but you do lose half of the max power of the radio. Also again the resistor power rating should be at least twice that of the requirement which would mean it should match the radio itself. So if the radio can put out 50 watts you need a 50 watt power resistor and it needs to be mounted correctly. Mounting methods can be found on the manufacturers sites that produce the resistors.

Just to be clear, two speakers that are wired in parallel have both leads connected to each other and they must be phased such that they are in phase with each other. That means the two positive terminals connect together and the two negative terminals connect together.

To wire two 4 Ohm speakers in series, only one wire from each is connected together. The positive from one speaker is connected to the negative of the other speaker, and the two loose ends become the wires that go to the radio. If you wire two positives together or two negatives together the speakers will be out of phase with each other and that will reduce the total audio power that emanates from the speakers as a pair.
Likewise if you connect two 8 Ohm speakers in parallel and you connect each positive to each other negative, they will also be out of phase. Both positives must be connected together and both negatives connect together.

If you are ever unsure about which terminal is positive and negative, you can use a small battery such as an AAA type and connect it to the speaker wires momentarily and watch which way the speaker cone moves. If the cone moves out then mark the terminal with the positive AAA battery terminal connected to it as plus (+) and mark the other terminal minus (-). If the cone moves in then mark them the opposite or just reverse the battery and then mark as previously described.
Once you get both speakers marked you then know exactly how to connect them together and to the radio.
Just to note, it does not matter which terminal you call plus and which minus but you have to stick to the same convention, so when the cone moves outward i call the positive terminal of the speaker the plus (+) terminal when it is connected to the plus (+) terminal of the battery, and the other terminal minus. It make a little more sense kind of.
With the resistor it does not matter the resistor is not polarized so if you flip the connections of the resistor it will be the same. The speakers are different though they must be connected properly together and also properly to the radio terminals always observing the polarities.