OLD amp Vs NEW amp - Yamaha AX-1090 vs Yamaha A-S801

[Swerd]

The closest I could find in the USA are these
https://www.madisoundspeakerstore.com/auto-woofers/scanspeak-silver-series-30w-4558t06-12-aluminum-cone-subwoofer-each/

Scan Speak recommends a sealed box from 1.25 to 1.5 cubic foot (35.4 to 42.5 L) for one of those woofers. Two woofers would require double the volume. If your design is 70 to 85 L in internal volume and is closed, the impedance should not be difficult for your Yamaha amp.

 

[paul.arhitex]

The closest I could find in the USA are these
https://www.madisoundspeakerstore.com/auto-woofers/scanspeak-silver-series-30w-4558t06-12-aluminum-cone-subwoofer-each/

Scan Speak recommends a sealed box from 1.25 to 1.5 cubic foot (35.4 to 42.5 L) for one of those woofers. Two woofers would require double the volume. If your design is 70 to 85 L in internal volume and is closed, the impedance should not be difficult for your Yamaha amp.

yep that's true - i guess the this OLD yamaha amp would be able to drive these at least.. maybe 40-50% of what my DIY loudspeakers can do

 

[lovinthehd]

make sense what u say and yes the old one is in a very good condition - i just need a 2 channel amp to drive my front BIG speakers in a future DTS:X home theater receiver setup.

- Normally i would prefer 2 monoblocks or an amp that has more than 2X300w 8ohms but.... i found just expensive on the used market and i cant afford to buy Emotiva in this moment

Why are you looking at integrated amps if this is just part of another system?

 

[TLS Guy]

yep that's true - i guess the this OLD yamaha amp would be able to drive these at least.. maybe 40-50% of what my DIY loudspeakers can do

It is not optimal to wire speakers in series. Where did you get the crossovers from? You can not use generic crossovers.

 

[paul.arhitex]

It is not optimal to wire speakers in series. Where did you get the crossovers from? You can not use generic crossovers.

no no not the 2 speakers are in series - just the drivers inside each speaker are(2woofers - 2mids)
- crossover was custom made by someone that is doing this for a living

 

[TLS Guy]

no no not the 2 speakers are in series - just the drivers inside each speaker are(2woofers - 2mids)
- crossover was custom made by someone that is doing this for a living

I know that but wiring drivers in series, especially woofers is still not optimal, as one tends to drive the other.

 

[paul.arhitex]

I know that but wiring drivers in series, especially woofers is still not optimal, as one tends to drive the other.

it's possible that u are right / i imagine that because in series the current first hits the 1st driver and after is traveling to the second driver and in Parallel both of the drivers are hit in the same time.
But then again all the big audiophile brands that have a lot of drivers on a single speaker or arrays of drivers can't connect all of them just in parallel so some of them are also in series or they have a combination of series & parallel.

For my speakers.. if i detect any problem i can change that in the future because the design is somehow modular.

 

[3db]

it's possible that u are right / i imagine that because in series the current first hits the 1st driver and after is traveling to the second driver and in Parallel both of the drivers are hit in the same time.
But then again all the big audiophile brands that have a lot of drivers on a single speaker or arrays of drivers can't connect all of them just in parallel so some of them are also in series or they have a combination of series & parallel.

For my speakers.. if i detect any problem i can change that in the future because the design is somehow modular.

Don't forget about skewing the phase of the signal when going through drivers wired in series.

 

[paul.arhitex]

Don't forget about skewing the phase of the signal when going through drivers wired in series.

skewing the phase of the signal? that is too complicated for me to understand in this moment - i'm just assuming that u say that the drivers will have a small delay between them when they move back and forward

 

[PENG]

Actually the old one is doubling dow it's power better in 4ohms

OLD amp 2x145 8‎Ω
max power 2x250 4‎Ω

NEW amp 2x100 8‎Ω
max power 2x160 4‎Ω

high dynamic power
8 / 6 / 4 / 2‎ Ω
OLD 220/290/360/460
NEW 140/170/220/290

You got me curious enough to download the manual of the AX-1090 and found the power specs to be:

Minimum RMS Output Power per Channel 8 ohms, 20 Hz to 20 kHz, 0.01% THD.........................................................145W+145W

6 ohms, 20 Hz to 20 kHz, 0.02% THD .........185W+185W

Dynamic Power per Channel (by IHF Dynamic Headroom measuring method) 8/6/4/2 ohms.........220/290/360/460W

DIN Standard Output Power per Channel [Europe model only] (4 ohms, 1 kHz, 0.7% THD) .........250W

Dynamic Headroom [General model only] 8/6 ohms......................1.81 dB/1.95 dB

IEC Power (8 ohms, 1 kHz, 0.01% THD) [Europe model only] .....................................................170W

The way it was specified, you have to read everything very carefully as they provided different "W" rating under different standards (IEC, DIN etc.) and operating conditions such as under different THD level. For example, the 250W into 4 ohm is for per channel, likely meant one channel driven only, and at a much higher THD or 0.7% and at 1 kHz, instead of the 145W+145W into 4 ohm rating that appears to be for 2 channel driven simultaneously; and at a much lower THD of 0.01%, and for 20 to 20 kHz.

In other words there is no sign of "doubling" down capability, not even close!!

The A-S3000, on the other hand has the power specified as:

8 ohm 20-20 kHz 0.07% THD...............100W+100W
4 ohm 20-20 kHz 0.07% THD...............150W+150W

No change in standards and operating conditions for both ratings, but if they were to specify it at 0.7% (10X) the distortion and at 1 kHz only, the 4 ohm output could possible come much closer to 200W, and then people may be led to believe that's "doubling down" when it really isn't.

I still think highly of the AX-1090, just want you to know it is not going to be as powerful as you may be led to believe from the published specs.

 

[paul.arhitex]

You got me curious enough to download the manual of the AX-1090 and found the power specs to be:

Minimum RMS Output Power per Channel 8 ohms, 20 Hz to 20 kHz, 0.01% THD.........................................................145W+145W

6 ohms, 20 Hz to 20 kHz, 0.02% THD .........185W+185W

Dynamic Power per Channel (by IHF Dynamic Headroom measuring method) 8/6/4/2 ohms.........220/290/360/460W

DIN Standard Output Power per Channel [Europe model only] (4 ohms, 1 kHz, 0.7% THD) .........250W

Dynamic Headroom [General model only] 8/6 ohms......................1.81 dB/1.95 dB

IEC Power (8 ohms, 1 kHz, 0.01% THD) [Europe model only] .....................................................170W

The way it was specified, you have to read everything very carefully as they provided different "W" rating under different standards (IEC, DIN etc.) and operating conditions such as under different THD level. For example, the 250W into 4 ohm is for per channel, likely meant one channel driven only, and at a much higher THD or 0.7% and at 1 kHz, instead of the 145W+145W into 4 ohm rating that appears to be for 2 channel driven simultaneously; and at a much lower THD of 0.01%, and for 20 to 20 kHz.

In other words there is no sign of "doubling" down capability, not even close!!

The A-S3000, on the other hand has the power specified as:

8 ohm 20-20 kHz 0.07% THD...............100W+100W
4 ohm 20-20 kHz 0.07% THD...............150W+150W

No change in standards and operating conditions for both ratings, but if they were to specify it at 0.7% (10X) the distortion and at 1 kHz only, the 4 ohm output could possible come much closer to 200W, and then people may be led to believe that's "doubling down" when it really isn't.

I still think highly of the AX-1090, just want you to know it is not going to be as powerful as you may be led to believe from the published specs.

Makes sense what u say - i was thinking that just the 8ohm power rating is important when u compare an AMP and that is important to be calculated full range 20hz -20khz at a THD lower than 0.1%
Correct me if i'm wrong and u need to care also about the 4ohm rating when u compare an amp.

But now let's think if the old amp is rated for 4 ohms, 1 kHz, 0.7% THD) at 250W we can assume that for 20hz-20kz 0.7% it would be between 100w -160w / i'am i assuming right?

Either way the old amp on paper is still more powerful than the A-S3000 at 8ohms and at a better THD also (0.01% Vs 0.07%)

Let's not forget that the old one when it was new it was around $1000 and with inflation maybe maximum $2000 in today's money - the A-S3000 today costs $6999

 

[Swerd]

I know that but wiring drivers in series, especially woofers is still not optimal, as one tends to drive the other.

Don't forget about skewing the phase of the signal when going through drivers wired in series.

Every driver has a voice coil with alternating current (AC) running through it. It can act as an inductor, similar to the low-pass filter inductors in a passive crossover. If two woofers are connected in series, the inductance from the first woofer's voice coil can, in theory, affect the sound signal going to the second woofer. The amount of filtering depends on the size and inductance of the voice coil. Those Scan Speak 12" woofers have a voice coil inductance of 0.83 mH. That isn't a low value, but I'm not sure if that is large enough to make problems. Confounding matters is the fact that the voice coil moves with that AC signal, so in fact the amount of inductance can vary with the musical signal.

In addition to the possibility of a low-pass filtered signal, a single inductor creates a delay in the timing of an AC signal. The phase (0 to 360 degrees) of the current lags behind that of the voltage by 90°, or ¼ of the time it takes for a full AC cycle. If the signal is 100 Hz, 100 cycles per second, that current delay is 0.0025 seconds. Is that a significant phase shift or not? Again, this lag time can vary with the musical signal.

To be honest, I'm not sure whether these theoretical reasons to avoid using woofers in series actually generate a significant audible problem in your speakers, but it can be easily avoided.

I hope that helps explain things.

 

[PENG]

Makes sense what u say - i was thinking that just the 8ohm power rating is important when u compare an AMP and that is important to be calculated full range 20hz -20khz at a THD lower than 0.1%
Correct me if i'm wrong and u need to care also about the 4ohm rating when u compare an amp.

But now let's think if the old amp is rated for 4 ohms, 1 kHz, 0.7% THD) at 250W we can assume that for 20hz-20kz 0.7% it would be between 100w -160w / i'am i assuming right?

Either way the old amp on paper is still more powerful than the A-S3000 at 8ohms and at a better THD also (0.01% Vs 0.07%)

Let's not forget that the old one when it was new it was around $1000 and with inflation maybe maximum $2000 in today's money - the A-S3000 today costs $6999

IMO, comparing the 4 ohms rating is quite important as it is a good indicator of how good the power supply is as well as the high current capability of the amplifier section. Also, most speakers do have impedance dip below 4 ohms, all my speakers do.

We don't have enough info to take an educated guess, but given the specs including the power consumption figures, I would guess at 20-20 kHz, 0.1% THD, the AX-1090 would probably do around 200W or a little more. That would be so call "continuous" rating, though it typically means minutes not hours. The so called dynamic output ratings will of course be much higher as the specs indicate.

I have to agree with you, that the AX-1090 is still going to be the more powerful one among the three, regardless.

 

[mtrycrafts]

- ...
Cheers!View attachment 18740

I am not sure the specs are fair between the 8 Ohm na 4 Ohm ratings. The 8 Ohm is at 20Hz-20kHz and 0.01% distortion. The 4 Ohm spec is at 1 kHz and 0.7% distortion.
That 220 watts needs to be derated by about 15% just for the bandwidth alone, then another cut for getting closer to that 0.01%.
Just an observation.

 

[ski2xblack]

I know that the IHF method tends to produce exaggerated numbers, but given the crest factor of music, it seems somewhat relevant. I wish more vendors published this data. Most of the time, for most typical listening levels and speaker sensitivities, average output power is probably a couple of watts or less, and it's only transient peaks that are really demanding.

As to the OP's dilemma, if it aint broke, don't fix (replace) it.

 

[paul.arhitex]

Every driver has a voice coil with alternating current (AC) running through it. It can act as an inductor, similar to the low-pass filter inductors in a passive crossover. If two woofers are connected in series, the inductance from the first woofer's voice coil can, in theory, affect the sound signal going to the second woofer. The amount of filtering depends on the size and inductance of the voice coil. Those Scan Speak 12" woofers have a voice coil inductance of 0.83 mH. That isn't a low value, but I'm not sure if that is large enough to make problems. Confounding matters is the fact that the voice coil moves with that AC signal, so in fact the amount of inductance can vary with the musical signal.

In addition to the possibility of a low-pass filtered signal, a single inductor creates a delay in the timing of an AC signal. The phase (0 to 360 degrees) of the current lags behind that of the voltage by 90°, or ¼ of the time it takes for a full AC cycle. If the signal is 100 Hz, 100 cycles per second, that current delay is 0.0025 seconds. Is that a significant phase shift or not? Again, this lag time can vary with the musical signal.

To be honest, I'm not sure whether these theoretical reasons to avoid using woofers in series actually generate a significant audible problem in your speakers, but it can be easily avoided.

I hope that helps explain things.

your explanation was easy to understand
- in my case if the loudspeakers will not sound bad i will apply this just for the next speakers i will build.

ps: dose this theory apply also for 2 midrange drivers in series or multiple tweeters in series ?

 

[paul.arhitex]

I am not sure the specs are fair between the 8 Ohm na 4 Ohm ratings. The 8 Ohm is at 20Hz-20kHz and 0.01% distortion. The 4 Ohm spec is at 1 kHz and 0.7% distortion.
That 220 watts needs to be derated by about 15% just for the bandwidth alone, then another cut for getting closer to that 0.01%.
Just an observation.

no, you are right - 2cuts / 1 for 20hz-20khz and one for the THD

 

[PENG]

skewing the phase of the signal? that is too complicated for me to understand in this moment - i'm just assuming that u say that the drivers will have a small delay between them when they move back and forward

He probably meant connecting from amplifier + to first speaker A's +, then from speaker A's - to speakers B's + and then from speaker B's - to the amplifier's -, but I am sure that's how you did it already.[/QUOTE]

 

[PENG]

skewing the phase of the signal? that is too complicated for me to understand in this moment - i'm just assuming that u say that the drivers will have a small delay between them when they move back and forward

I know that the IHF method tends to produce exaggerated numbers, but given the crest factor of music, it seems somewhat relevant. I wish more vendors published this data. Most of the time, for most typical listening levels and speaker sensitivities, average output power is probably a couple of watts or less, and it's only transient peaks that are really demanding.

As to the OP's dilemma, if it aint broke, don't fix (replace) it.

Agree, the key word is "somewhat". Remember people used to jump on the band wagon about how HK's specs are so conservative, just because of their nice ACD numbers relative to their 2CH numbers yet their 2CH numbers sucked on bench tests when compared to Yamaha's equivalent models, when Yamaha has to doing the right thing all along, somewhat...

 

[Swerd]

your explanation was easy to understand
- in my case if the loudspeakers will not sound bad i will apply this just for the next speakers i will build.

My explanation oversimplified things. I'm not trained in electrical engineering and I tried to avoid any major mistakes. PENG (thank you ), who is an EE, gently pointed out several of my mistakes:

"I would like to comment that 90° is the worst case, that is, if the woofer acts like a pure inductor with only inductance. In practice the phase angle will be much less because the woofer coil also has resistance. Your example of 100 Hz, the lower the frequency the lower the inductive reactance it is going to be the resistive part will be constant. The phase angle/delay is mainly affected by the inductive reactance and resistance.

Further, in a series circuit, the current is the same through both speaker voice coils so in actual fact the phase angle between the voltage and current will be the same. There will be some capacitive effects but for short runs in free air that will be totally negligible. To conclude, the delay you referred to will be the same for both speakers. In electricity flow in such circuit it really makes no difference between the so called first or second or third in line, unless there are parallel branches involved too, obviously."​

I don't believe these corrected details change any of my previous conclusions – that drivers wired in series in loudspeakers are better avoided. However that does not mean that it can never be done, only that amateur DIY speaker builders, such as myself, don't know how to do it. I hope all that is crystal clear .

ps: dose this theory apply also for 2 midrange drivers in series or multiple tweeters in series ?

Yes, it applies to any drivers wired in series, in theory.

In theory, there is no difference between theory and practice. In practice, there almost always is .