I’m thinking of buying a pair of vintage loudspeakers for my stereo (Goodmans Triaxiom 1220c 12 ").Impedance is 15/16 ohms…30 - 20,00 C.P.S.
I’ve always had speakers that are 8ohm jobs and I’m wondering if these will be OK for my setup .The amp is an older AKAI unit and on the back it says that ohmage is from 4 to 16,so that part should be OK…does the 15/16 ohms on these speakers make for a ‘different’ sound.I believe that these were used with a Hammond Organ although they are home stereo speakers.
Why do they stuff that fibreglass bat stuff inside speaker boxes ? I hate that stuff and if I DO get these speakers I’ll remove it. What’s its function ?
3.The cabinets are huge (1.2 metres high x .5 metre thick) with the speakers at the top and a ‘brick size’ hole at the bottom … is there any info around regarding building smaller cabinets and , perhaps, making them sound better.? The listening area is a shed 9metre x 7 metre..
Thats about all for now..thanks Chiffers.
Can you try the speakers to see whether you like them or not? Old speakers often have some deterioration in the foam stabilizing rings around the cones. I had to replace these on my component speakers. it sounds to me like the speakers will match up OK with your amp.
The impedance should be OK with your amplifier as long as it says it can handle 16 ohms. Your amplifier will sound a little quieter than with 8-ohm speakers as long as everything else is equal, which they aren’t, because your earlier speakers were presumably of an entirely different type. So you won’t know how loud they are until you try.
As for difference in sound.. it’s difficult to tell, because the impedance you get is the result of a design which takes several things into account. But in general you will find 4-ohm speakers where you want loud sound and maybe care slightly less about distortion. Obviously the amplifer must be able to handle it (because the actual impedance can go much lower.. see below).
Note that ‘4 ohms’, ‘8 ohms’, or ‘16 ohms’ is just a nominal value.. the actual impedance will vary greatly throughout the frequency spectrum, and what you want to avoid is that the impedance for any frequency is lower than the amplifier can handle (or it’ll clip). There used to be a diagram at the back of loudspeakers, or at least with the documentation, which showed the impedance curve. Well, I haven’t been a hi-fi geek for some decades now so things may have changed since my day, at least in other fields documentation of any kind seems to just not be provided with products anymore.
1 - If your speakers will drive an 8 ohm load, it will drive a 16 ohm load. The nominal load an amplifier will drive is a function of how much current it can drive. It all goes back to voltage = resistance x current.
2 - The fibreglass bat stuffed in the enclosure makes the enclosure look larger to the speaker driver. There is a set of calculations (along with a lot of developmental testing) used to determine how large an enclosure needs to be in order to correctly back load the speaker driver. If you want to get into this, search Theile-Small equations. Bottom line - if you remove the stuffing, the speakers will not work they way they were intended, and you will likely blow a driver.
3 - Again, the driver enclosure is sized to the driver. Despite what the marketeers at Bose claim, you can’t get low frequencies from tiny speakers in tiny boxes. Without adding a feedback circuit with an accelerometer mounted on the speaker cone/voice coil, and a circuit in the amplifier, a smaller box won’t work for a set of drivers that need a large box.
To the OP questions:
16 ohms - means that for a given output these speakers will demand less current from your amplifier - easier for the amp to drive and typically the amp will produce less distortion doing so. As to loudness there are so many other variables that it is impossible to say - but given that these are vintage speakers, what they look like, and their size it is likely that they are quite efficient (typical vintage amplifiers were much less powerful and so speakers tended to be more efficient in order to work with less power - or maybe everybody just listened at lower levels!). If they are efficient they may play quite loud while demanding less power from the amp.
That stuff you hate inside the speaker reduces reflections inside the cabinet making it sound less boxy and it also makes the cabinet appear larger in volume - removing it will change the sound of the system most probably in a negative way. It is possible to use other materials to damp the cabinet - an old classic was long haired wool, a more modern material is some sort of polyester (or something else?) batting, either of these would be much nicer to deal with than fiberglass. But I’m pretty sure you want something inside the cabinet.
The brick size opening makes these a bass reflex design (which all other things being equal) produces louder and lower bass but a bit more boomy in many cases. The size of the cabinet is very important to the sound of the bass - you can’t just dump the drivers into a smaller cabinet and expect them to work correctly. These drivers were probably designed to work in larger cabinets - larger cabinets also tend to produce more efficient speakers.
does the 15/16 ohms on these speakers make for a ‘different’ sound
The answer is: In of itself 16 v 8 v 4 ohms does not make for any specific differences in sound, except designers choosing one of these often have somewhat different goals and so probably there tend to be specific differences!
It is my impression that 16 ohm speakers tend to be more efficient - more efficient speakers often have a certain ease to the sound, perhaps a little more colored, and sometimes a bit more live sounding. But these are generalizations that certainly do not apply to all 16 ohm speakers.
Thanks so much for the replies and information everyone…they answered all my concerns.
The Fibreglass Batts…absolutely horrible stuff.If I get this on my skin a painfull and itchy rash will soon apear…I’ve seen a synthetic material that is used as a replacement for the fibreglass yuk and if I do get the cabinets/speakers… I’ll get some of this.
I believe that the cabinets are not a Goodmans product but were made especially for the Organ…So,seeing that they’re for the shed and there’s plenty of room (at this stage anyway…sheds DO tend to fill up !) I might just leave them as is…I’ll decide later…maybe they’d be good for the Organ but not for Hi-Fi ..
Y’all may be interested in the story behind the speaker situation …
About a month ago I put an ad in the local paper asking if anyone was interested in playing Gypsy Jazz..not one call ,except from an 83 year old trombone player ! Trombone says I,what are we supposed to do with that ! I gave him a call and what a lovely man he is.The next time I was in town,I called around an introduced myself.We chatted for ages and he played me some tunes on the ‘bone’…Improvising over some Jazz standards and changing key with ease…he’s a great player…anyways… I was admiring these big speakers(containing Goodmans 1220c speakers) and he said that he wanted to get rid of them as they were too big for the room…‘I asked how much and he replied “they’re a Tin Roof mate..on the house”..never one to pass on something for free,I grabbed them.
Sadly,when I got them home and had a closer look,the tweeter assembly was missing from one speaker and the voice coil on the other was scraping …so here I is,lumbered with two great big speaker boxes that dont work .
I have a policy that I never sell what has been given to me as gift,so I contacted Paul about this and he said go for it and sell,I wont be offended..So I did..on Ebay for $120.00..
I was a bit disapointed about the speakers being broken as they have a good vibe/reputation about them and I thought they would fit in with other vintage stuff I have.
So…these other Goodmans have apeared on the scene and I’m thinking "hey…if I can get these for $120.00 or thereabouts,I’ll still be getting a pair of Goodmans 1220c’'s for free" … make sense ? Sound like a plan ??
I’ll know later on in the week what’s happenning…
Once again…thanks for your input folks…greatly apreciated..If I do get the speakers I’ll post again…Might even be on the lookout for another vintage tube/valve amp !..
Cheers from OZ …
A late reply, but to answer the stuffing question.
In every field of endevour, there will be aspects which are hotly debated, and in which less-than-honest business people will insinuate themselves. Speaker stuffing material is one of these topics. In my experience, polyfill stuffing used in pillows and stuffed animals works just as well as fibreglass, and is not an apparent irritant. There are those who will tell you that only Australian, or New Zealand wool, washed in the head waters of the river that feeds into Shangri-la will do. These same people will also tell you that nothing less than Monster cables will transmit any signal without the distortion caused by skin effect There are companies that sell something that looks like polyfill, but sells pound-for-pound the same as silver. Apparently, this magic filling is hollow, which allows better heat dissipation and a more efficient speaker system.
That rings a bell - but from insulation for high tech camping stuff. It is unlikely that something like this is specifically made for audio so it might be possible to source it from a fabric store. It may well be better than the standard stuff. Almost anything is better than handling fiberglass!
There is a lot of snake oil in the audio business - thing is not all of it is snake oil (or snake oil is what you want).
Thanks for the extra info Dave and Highwood…Horible stuff that fibreglass matting..
If I did get those speakers ..the first job would have been to remove it …and get some of that Aussie/Kiwi wool …
,except from an 83 year old trombone player ! Trombone says I,what are we supposed to do with that ! I gave him a call and what a lovely man he is.The next time I was in town,I called around an introduced myself.We chatted for ages and he played me some tunes on the ‘bone’…Improvising over some Jazz standards and changing key with ease…he’s a great player…anyways… I was admiring these big speakers(containing Goodmans 1220c speakers) and he said that he wanted to get rid of them as they were too big for the room…‘I asked how much and he replied “they’re a Tin Roof mate..on the house”..never one to pass on something for free,I grabbed them.
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… make sense ? Sound like a plan ??
…
There are companies that sell something that looks like polyfill, but sells pound-for-pound the same as silver. Apparently, this magic filling is hollow, which allows better heat dissipation and a more efficient speaker system. 