I think that it will work the way that you have described. It's essentially the same as the set up described in the Yamaha user manual for the "two sets of speaker terminals" case. Keeping in mind that the A and B speaker outputs of an amplifier are simply two sets of terminals connected in parallel and with an electrical switch in the circuit.
On this video, Paul McGowan, the owner of PS Audio, also says that it will work that way with a tube amp. He adds that you should keep your speakers full range, in short you shouldn't use the speaker level output of the sub.
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That yamaha sub has a compensation circuit for the speaker signal. That is something very different than just connecting the speaker output of an amp to the line inputs of a powered subwoofer.
I would not trust Paul for that, he often spread ******** about hifi in his vlogs. That is more than once proven.
Plenty of subs out there with speaker level inputs
Including many car systems that had the option.
A Speaker line input source of 600 ohms on the sub combined with a 8 ohm load parallel
is 7.89 ohms
So yes it will work.
Follow the directions provided as shown by the manufacture
Including many car systems that had the option.
A Speaker line input source of 600 ohms on the sub combined with a 8 ohm load parallel
is 7.89 ohms
So yes it will work.
Follow the directions provided as shown by the manufacture
Ok, thanks. I'll search online a used powered subwoofer with speaker level inputs. I'll start with one to see how it works and if it's ok I'll buy a second.
The old Yamaha YST line is the most common for sale in Italy. They all have speaker level inputs. It's probably not the best subwoofer, but there's a lot of them available so it's going to be easy to find a second of the same model.
The old Yamaha YST line is the most common for sale in Italy. They all have speaker level inputs. It's probably not the best subwoofer, but there's a lot of them available so it's going to be easy to find a second of the same model.
Can you please elaborate on what the "compensation circuit" is and how it works?
Note that Yamaha clearly state: "This unit can be added easily to your existing audio system by connecting to either the speaker terminals or the line
output (pin jack) terminals of the amplifier." I assume their advice would be valid, as they designed the equipment. Of course, just to be clear, when they mention the line output/input terminals they mean the low-level RCA connections, not the high-level speaker wire connections.
As far as I know, based on the user manual, the Yamaha YST-SW45 is an Active Servo subwoofer. This means that it has a control circuit that adjusts the driver's response based on a sensor placed somewhere on the driver itself. This circuitry would be isolated from the external stereo amplifier, whose characteristics are unknown.
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I think that what the video has mentioned is largely correct. You can use the speaker level output of a subwoofer if it is present, as it could greatly simplify and shorten your speaker wiring in some setups.
You will note that subwoofers generally do not have an independent speaker level output, as that would require an amplifier to be present; that's not their job and it would add extra unnecessary cost. If a subwoofer does have terminals for connecting the main speakers, then these are simply working in a pass-through mode, without any independent amplification. The same signal is present on such a subwoofer's high-level speaker outputs as is present at its high-level speaker inputs.
The keeping of one's speakers full-range when using a subwoofer is open to debate. It is the simplest form of connection, and it is often sometimes said that it ensures that the "character of the main speakers" is maintained. It also just requires appropriate low-pass filtering and amplification/gain to be applied to the subwoofer to achieve a reasonable sort of blending of the subwoofer's low-frequency output with that from the main speakers. In that way, it is relatively simple, at least theoretically, to add a subwoofer in this manner.
However, there are significant benefits to applying high-pass filtering to the main speakers when adding a subwoofer. These include reducing their driver excursion when reproducing very low frequencies and, as a result, also significantly lowering the power that goes into the main speakers. This will help to lower the distortion produced by the main speakers. The subwoofer is designed to be able to handle low frequencies and their large excursion requirements, and it has additional amplification on board to do that job properly. This amplification is usually quite powerful to meet the demands of low-frequency sound reproduction. Choosing appropriate combinations of low-pass filtering on the subwoofer and high-pass filtering on the main speakers is likely to produce a better integration/blending between the acoustic outputs of the subwoofer(s) and the main speakers.
Agreed. REL subwoofers come to mind...
600 ohms seems a bit low to me. I was thinking that the speaker level input circuit impedance would be closer to 10k ohms. That would produce an 8//10k parallel load of 7.994 ohms.
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The Yamaha YST-SW45 subwoofer seems to be a moderately capable unit for its driver size. It's only an 8-inch woofer, so that's only 64% of the radiating area of a 10-inch driver and only 44% of the radiating area of a 12-inch driver. The latter will likely have a larger linear excursion capability, magnifying the difference even further. It will provide an excellent "voicing" match to your Altec loudspeakers, which seem to have quite limited bass response.
Having said that, the YST-SW45 has a reasonable bass extension for an enclosure whose gross volume is a compact 27 liters. The published frequency response curve is shown below. With the low-pass filter set to 100Hz, this subwoofer will be −10dB at 30Hz, and −3dB at about 37Hz, which isn't too bad. With its low-pass filter set to 50Hz, the –3dB point will decrease a little to about 33Hz. These results are quite good for an 8-inch driver, and show that Yamaha has tried to ensure that the subwoofer won't easily be overloaded by infrasonic content outside its nominal passband.
With your particular use case, I would suggest that you go for a twin-subwoofer configuration. This will reduce the load that would otherwise be placed on a single subwoofer, and it will help to ensure linear operation at higher listening SPLs. The low-pass filter on the subwoofer is probably going to need to be set to around 80Hz or so. I would suggest that you do a near-field measurement of the Altec Lansing 409-8c coaxial speakers to get a good idea of their low-frequency cut-off point (I assume that they are in a sealed/closed-box enclosure). Their measured cut-off point will strongly guide your choice of low-pass cut-off frequency to be used on each subwoofer.
From your photograph of the speaker layout in your listening room, and your main speakers, it would be possible to place the subwoofers next to or behind the main speakers. This would help minimize any phase difference between the bass from each main speaker and its complementary subwoofer, potentially making integration of the subwoofers easier to accomplish to a high standard.
Depending on your main speakers, the subwoofers may or may not require a polarity inversion to attain the best integration. This may require a bit of experimentation, and ideally some measuring gear. Unfortunately, the YST-SW45 does not seem to have a polarity/phase switch, so you would need to switch the cables around at the speaker terminals; that's not too difficult to do.
Considering your existing speaker layout, in a dual subwoofer configuration, placing each subwoofer next to its complementary speaker would enable you to use your existing speaker cable for each connection. This would of course be connected to the "From Amplifier Input 1" terminals. You would then need a very short run of speaker cable to go from the "Output To Speakers" terminal to the immediately adjacent main speaker. This would help to minimize the effects of any additional speaker cable resistance.
I agree with the recommendation to use two subwoofers. It's the best way to go, and will enable good results to achieve on a more frugal budget.
The t.racks DSP 4x Mini Pro seems to be a very capable controller for the price. It does require the use of XLR connectors, which does add a little bit of complexity unless the equipment already at hand has provision for those. The DSP unit seems to have a good feature list: delay, low-pass filtering, high-pass filtering, and parametric EQ filtering. It can handle the stereo channels required of a hi-fi system.
From one of the pictures in the user manual, the filters include the 4th-order Linkwitz–Riley topology, which could prove beneficial when integrating subwoofers with the Altec 409-8c speakers. Those speakers would probably benefit from some high-pass filtering to help reduce the low frequencies below 100Hz that reach them. They would be expected to work much more linearly as a result, with reduced levels of distortion.
The parametric EQ in the t.racks DSP 4x Mini Pro could also be used to provide some adjustment of the frequency response of the Altecs in order to get a flatter overall response. This would enable the user to adjust the voicing of the Altecs to be more accurate and/or suit their listening preferences.
Hello. The Altec 409-8c are in a ported enclosure. It was realized during the early Seventies by the italian Altec dealer. Nearly identical to a ported box designed by the japanese Altec dealer at the same time, which was sold as "DIG". Most of these Altec 409-8c are now in Japan and most of them are in ported enclosures same size as mine. The Qts of 1.54 wouldn't let you design now a bass reflex enclosure so small, and not even a closed box so small, but in same way it works. Probably a speaker design software wouldn't even let you calculate an enclosure with those T/S parameters. The best configuration would probably be an open baffle. But in some way it works.
I can probably hear from those Altec some 70 hertz.
As for the subwoofer, my first enemy is weight. I've got Fibromyalgia and can't lift heavy weights. It hurts a lot. Nothing in my system weights more than 9 kg. 9 Kg is my limit, so I can't buy the really good stuff. It's too heavy.
The Yamaha YST-SW 45 weights 9 kg and I can probably cope with that. I can start with one and see if I like a subwoofer. Then I can easily find another. Those Yamaha are the most common used subwoofers for sale in Europe. We haven't got here all the good used stuff they've got in North America.
I'm also in talks with a guy who has got an used Polk Audio PSW111 without the front grille, at an interesting price. This is a compact design with a class D amplifier, has got 150 W RMS and an eight inch woofer. It probably goes down to 38 hertz. It weights also 9 kg.
On this video, you can hear what these small Altec can do with the help of two subwoofers. In this video the Altec is in a small ported enclosure, probably from a JBL speaker. You can see also a tweeter but it isn't connected:
I can probably hear from those Altec some 70 hertz.
As for the subwoofer, my first enemy is weight. I've got Fibromyalgia and can't lift heavy weights. It hurts a lot. Nothing in my system weights more than 9 kg. 9 Kg is my limit, so I can't buy the really good stuff. It's too heavy.
The Yamaha YST-SW 45 weights 9 kg and I can probably cope with that. I can start with one and see if I like a subwoofer. Then I can easily find another. Those Yamaha are the most common used subwoofers for sale in Europe. We haven't got here all the good used stuff they've got in North America.
I'm also in talks with a guy who has got an used Polk Audio PSW111 without the front grille, at an interesting price. This is a compact design with a class D amplifier, has got 150 W RMS and an eight inch woofer. It probably goes down to 38 hertz. It weights also 9 kg.
On this video, you can hear what these small Altec can do with the help of two subwoofers. In this video the Altec is in a small ported enclosure, probably from a JBL speaker. You can see also a tweeter but it isn't connected:
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The Yamaha YST subs were very sophisticated for their time. I worked on a version for the UK market.
I second Witwald's advice to use 2 x Yamaha subs. If you have a separate preamp feeding your amp, you should try the phono inputs & outputs on the Yamaha so you can take advantage of their electronic xover which will roll off your Altecs as required.
If you don't like this, just go back to using the speaker inputs & outputs but then you operate the Altecs full range.
I second Witwald's advice to use 2 x Yamaha subs. If you have a separate preamp feeding your amp, you should try the phono inputs & outputs on the Yamaha so you can take advantage of their electronic xover which will roll off your Altecs as required.
If you don't like this, just go back to using the speaker inputs & outputs but then you operate the Altecs full range.
Thanks. I have just purchased online one Yamaha YST-SW45 and 4 meters of cheap QED 79 strands speaker cable.
The power handling of the Altec Duplex drivers is just 16 watt. I have got two integrated tube amps, the smallest push pull Cayin and the smallest single ended Line Magnetic. I haven't got separates.
When they deliver the Yamaha sub, I will start with one and then I will purchase another. There are several for sale. You can have it even for 50 euro.
According to the user manual, with one sub I have two options:
With two subs I have to study the matter.
Thanks anyone for your help.
The power handling of the Altec Duplex drivers is just 16 watt. I have got two integrated tube amps, the smallest push pull Cayin and the smallest single ended Line Magnetic. I haven't got separates.
When they deliver the Yamaha sub, I will start with one and then I will purchase another. There are several for sale. You can have it even for 50 euro.
According to the user manual, with one sub I have two options:
- From the amp's speaker terminals to the speaker level inputs and then from the speaker level outputs to my speakers, through the sub crossover
- From the amp's speaker terminals in parallel with the speakers to the speaker level inputs of the sub, keeping my speakers full range.
With two subs I have to study the matter.
Thanks anyone for your help.
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Looking at the diagrams in the user manual of the Yamaha YST-SW45, it does not appear to have any RCA connector outputs that are high-pass filtered. High-pass filtered RCA connector outputs on a subwoofer are altogether a bit uncommon.
The user manual describes the connection of two subwoofers using the speaker terminals as shown below. For some unknown reason, Yamaha decided to draw the left speaker on the right and vice versa!
You seem to be leaning towards placing each subwoofer in close proximity to its main speaker. This setup would require a long speaker cable run from the amplifier to the speaker input on the subwoofer, followed by a short cable connected from the subwoofer's "Output To Speakers" to the relevant main speaker's terminals.
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In Japan, they also drive on the wrong side of the road, so that is only logical.