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CosmicJazz

Tri-amp 3 way speakers, still worth if using a multi-channel amp? (HiFi Stereo)

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Hello to all,

Recently I’m thinking about tri-amp the 3 way loudspeakers that I’m planning to build, I know that the optimum way is with separated amps for each driver, but due the high costs of acquire 3 amps, I’m thinking about a multi channel amp.

Appreciate very much the thoughts from more experienced people about this subject, do you think that with a multi channel amp, and a very nice crossover, the system still will provide the great advantages of an active multi amplified system? 

Will put here the equipments that I have in mind, in order to provide some context.

This are the speakers that I’m planning to build:


3 way: 12" woofer + radial horn + super tweeter 
https://www.fostexinternational.com/docs/speaker_components/pdf/recom_enclose/w400aII_encl.pdf
(the exact drivers are the showed on the third option plan)

Active Crossover:
http://www.accuphase.com/cat/f-15len.pdf or http://www.accuphase.com/cat/f-25en.pdf
F15-L appears for reasonable prices from time to time...

Now, the amp it’s the big question...

I noticed that if choose a multichannel amp, mostly of then are designed for home theaters or pro audio... what about HiFi Stereo?

 

This Accuphase from 2001: http://www.accuphase.com/cat/px-600e.pdf

Appears to be the logical option, when considering the crossover, but this don’t appear very often, but according to my researches, they appear from time to time in Japan, found some in online auctions that was sold for prices not so extravagant... still costly, but, considering the price of acquire separated amps for the same performance level, still worth it..

 

I'm wondering how most of the multi channel amps specific designed for HT are voiced... if there's something on their design that is more suitable for movies sounds effects, and etc.. and not so refined for music playback only, from vinyl CDs, and etc...  Maybe this happens with some models, but is not a common thing in all?

Anyway, that’s it, appreciate very much all the thoughts about the subject, advices, amps suggestions...

Many thanks, best regards.

Edited by CosmicJazz

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3 hours ago, CosmicJazz said:

I know that the optimum way is with separated amps for each driver

Huge assumption, and not necessarily correct. I've built both ways usually with no sonic difference, providing you choose the correct amps.

 

I'm not a fan of the Fostex drivers, except some of the cheaper widerange mids. The expensive ones are underperforming and overpriced.

 

I don't like the xovers either; only 2 slopes, no EQ, no delay and the need to adjust F via different boards. Plus they're vintage and  may/may not  work correctly or be reliable. Get a decent DSP. I haven't used an analog xover since 2001.

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6 hours ago, A9X said:

I don't like the xovers either

100%.

They are likely to be nowhere near sufficient (perhaps understatement) alone to create a high performing speaker.

 

 

It doesn't have to be "DSP" .... but you do have to design an appropriate correction network, for the driver which won't be a straight HP or LP filter.

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Hello, thanks for your contribution guys, really appreciate.

 

Well, I'm don't think a  active digital crossover will be the better option for me, as I'm a vinyl guy, don't want the phono signal be converted to digital, and then to analog again, I know that some people advocate that there's no harm to the sound via this procedure, but I think don't make much sense, I think DSP must be a amazing solution for digital sources... but not for me.

 

Class D it's a interesting option for amplify the 12" woofers, it's also nice that there's a lot of options with a reasonable value and great performance.

Hello, thanks for your contribution guys, really appreciate.

 

Well, I'm don't think a  active digital crossover will be the better option for me, as I'm a vinyl guy, don't want the phono signal be converted to digital, and then to analog again, I know that some people advocate that there's no harm to the sound via this procedure, but I think don't make much sense, I think DSP must be a amazing solution for digital sources... but not for me.

 

Class D it's a interesting option for amplify the 12" woofers, it's also nice that there's a lot of options with a reasonable value and great performance.

 

 

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11 hours ago, Stump said:

What do you think of the DEQX setup

I've got one. It'll kill the Accuphase.

 

12 hours ago, Stump said:

with D class Amps?

Which class D amps? Hypex, yes, especially above the midbass.

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4 hours ago, A9X said:

I've got one. It'll kill the Accuphase.

 

Which class D amps? Hypex, yes, especially above the midbass.

My active system will be run by 2 sets of Tube mono blocks.Given the possible downtime I would expect with tubes I will look at the Deqx A250x3 amps together with the Deqx HDP-5..

 

https://www.deqx.com/products/amplifiers/

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17 hours ago, Stump said:

You will be using some nice equipment.What do you think of the DEQX setup with D class Amps? Im going with Deqx and will look at there Amps later.

DEQX is a good tool.....  it offers the user a "process" to step through .... which can be helpful, but can also lead to bad shortcuts in the speaker design process if abused.

Like if there was a tool to help you design a car, by tuning the engine automatically .... but it let you get away with putting any gearbox in the car.    You could tune the engine "perfectly" around a completely stupid gearbox..... then "engine tuner" would tell you everything look "perfect"  (cos it's totally tuned) ..... but the car wouldn't be good.

 

Hope that analogy is helpful and makes sense.

 

 

The important thing with amplifiers is gain structure.

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17 hours ago, CosmicJazz said:

don't want the phono signal be converted to digital, and then to analog again

You should be more worried (times a billion) about designing poor speakers .... than an AD/DA conversion.

 

If seems unlikely you can correct the drivers to produce a coherent response with only simple HP/LP filters.....   but there might be something we don't know.   The devil is in the details.

 

17 hours ago, CosmicJazz said:

I think DSP must be a amazing solution for digital sources... but not for me.

Sure.... so no DSP then.

 

That doesn't free you from having to design correct/good filters for your driver.  How are you going to do it?

 

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2 hours ago, davewantsmoore said:

DEQX is a good tool.....  it offers the user a "process" to step through .... which can be helpful, but can also lead to bad shortcuts in the speaker design process if abused.

Don't use the auto tuning features then. Better to do it manually anyway.

 

2 hours ago, davewantsmoore said:

Hope that analogy is helpful and makes sense.

Having designed my own EMU, it's not a great analogy. In the real world there are only a limited number of gearboxes a given engine can be fitted with.

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I don't think DSP it's a good option for my project, as my main source is vinyl, can't conceive how can be a good thing the phono signal be converted to digital along the way, and back to analog again, don't make much sense for me... that's why I mentioned only the analog ones..

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21 hours ago, CosmicJazz said:

can't conceive how can be a good thing the phono signal be converted to digital along the way, and back to analog again,

Why is it a bad thing? SNR on analog is 60dB or so, bandwidth is 16-20kHz at best and bass is typically mono below some frequency, usually above 100Hz and channel separation is minimal.

A modern ADC has an SNR of >120dB, bandwidth of 96kHz and channel separation about the same as the SNR.

So pray tell, how is putting it through an ADC (post RIAA pre) a bad thing? I want technical reasons not audiophile woo-woo.

 

Here's how I see your implementation vs mine.

Accuphase:

Pros: Name cache

Cons: Old, potentially unreliable and have fun getting replacement FETs if needed.

Needs cards to set xover freq.

No EQ

No delay

Only one slope (which is what?), though 2 orders.

Tends too be pricey.

 

MiniDSP 4x10HD:

Pros: Multiple slopes and orders, able to be changed in a second.

Different presets so you can have differing EQ to compensate for recording issues

Lots of EQ, able to be changed quickly

Delay, because your driver's acoustic centres are going to vary, especially the mid.

 

Either way you're going to need to be able to measure to make decisions to optimise the project.

 

Speakers are not plug and play. My impression is you seem to think you can simply plug in the xover freqs, set levels and off you go. That will work to some extent, but in my long experience (>30 years with the last 18 DSP only, analog prior to that), it doesn't. You will need delay, most likely EQ and will need to be able to change the filter characteristic and/or order to get the drivers to integrate correctly.

 

Many times I've done the needle drop test, whereby a visitor sees my lower the cartridge onto a disc and then sits down to listen. However, I don't have the TT connected as source, it's a recording of the same LP played off HDD. Not one person has ever picked me up on it.

 

Actually, my advice is for you to save the money and build the passive version. Though I'm an active fanboy, kludging an active system together when (I think) you don't know what you're doing, or bothering to optimise it, is really a waste of time and money.

 

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Thanks for all the advices, will take a closer look at all that on the weekend.

 

Best regards guys.

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23 hours ago, CosmicJazz said:

I don't think DSP it's a good option for my project, as my main source is vinyl, can't conceive how can be a good thing the phono signal be converted to digital along the way, and back to analog again, don't make much sense for me... that's why I mentioned only the analog ones..

 

Hah - I used to think like you, CJ!  :lol:  I listen almost exclusively to vinyl ... and I had 3-way active speakers.  I used Rod Elliott's P09 XO boards for this.

 

I had this for 15 years ... but then I moved into a new house - and this new house was going to include a pair of subs, as I love Bach organ music (which my Maggies don't fully deliver)!  :)

 

Adding subs - and doing it properly - meant I had to delay the Maggies ... to line up with the subs.  (These subs were also further away from my ears than the Maggies.)  Which meant I had to switch to a digital XO - which could deliver the 4-way filters plus provide delay (and also do room EQ!).

 

So now I have my phono stage going into a high quality A2D converter and then into (the digital input of) my miniDSP 10x10HD.  As I'm using digital, rather than analogue, input:

  1. I am using a much higher quality A2D converter than the one in the miniDSP unit, and
  2. the miniDSP runs at 96kHz instead of 48kHz.

I can assure you the resulting sound - for vinyl - is much better than when I had 3-way analogue XOs ... and no subs.

 

Andy

 

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42 minutes ago, andyr said:

So now I have my phono stage going into a high quality A2D converter and then into (the digital input of) my miniDSP 10x10HD.

No disagreement at all with this. My ADC is an ESS based unit, though I also have a PCM4222 device as well.

I don't use an MD for xover; I have a PC based unit with an external pro SC.

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Bi-amping with Pioneer M-73, help me to understand please...

 

Please, appreciate very much clarifications about this application with the Pioneer M-73 power amp.  Here's the amp:

898587731_m73front.jpg.979053f003f1dc1b9e759be36cfec041.jpg

 

1194754061_m73back.jpg.20325bdf636127b21e3c8b7c36ce1852.jpg

 

Here's the situation:  

 

Considering a pair of 3 way loudspeakers, 12" woofer + radial horn + super horn tweeter, it's possible to amplify the 2 radial horns + 2 super horn tweeters, with just one Pioneer M-73?  I'm asking because the amp have two A Left speakers terminals + two B Right speakers terminals, and on the front, I see that is possible to select the A + B speakers selector at the same time, and also, when you see inside the amp, appears to have 4 separated channels, see the picture:

 

701289444_PioneerM73inside.jpg.3f47200f93aaac5db6f07c527bb658e6.jpg

 

 

So I will be in fact bi-amping the 2 radial horns and 2 super tweeters?

 

Appreciate very much the clarifications about it, many thanks!

 

 

 

 

 

 

 

 

Edited by CosmicJazz

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I think I have found the answer for my question, please let me know if I'm correct:

Consider passive crossover.

So if I choose to use 1 M-73 to amplify 4 speaker's drivers using the 4 speaker's terminals (A left horn + B left tweeter / A right horn + B right tweeter), and select A AND B speakers selectors to work at same time, i will be bi-wiring, that means: each amplifier's channel will be responsible for divide their power for 2 drivers right? this can be done only if the drivers don't go bellow 8ohms, correct?

I realized this is not a 4 channel amp, it's a 2 channel stereo amp, I was thinking it was a 4 channel amp, with 4 separated blocks, with each speaker's terminals connected to each block, just because of the inside look, (appears that are 4 separated amp blocks), but is not, it's just a stereo amp, correct?

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2 hours ago, CosmicJazz said:

I think I have found the answer for my question, please let me know if I'm correct:

Consider passive crossover.

So if I choose to use 1 M-73 to amplify 4 speaker's drivers using the 4 speaker's terminals (A left horn + B left tweeter / A right horn + B right tweeter), and select A AND B speakers selectors to work at same time, i will be bi-wiring, that means: each amplifier's channel will be responsible for divide their power for 2 drivers right? this can be done only if the drivers don't go bellow 8ohms, correct?

I realized this is not a 4 channel amp, it's a 2 channel stereo amp, I was thinking it was a 4 channel amp, with 4 separated blocks, with each speaker's terminals connected to each block, just because of the inside look, (appears that are 4 separated amp blocks), but is not, it's just a stereo amp, correct?

 

Looking at the specs for the Pioneer M-73 ... it appears to be a stereo amp.  So if you take spkr wires from both A & B outputs ... you will be bi-wiring (ie. wiring to both horns & tweeters, separately) but you won't be biamping.

 

Andy

 

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On 30/08/2019 at 2:43 PM, A9X said:

Don't use the auto tuning features then. Better to do it manually anyway.

Yes, that's my point.

 

On 30/08/2019 at 2:43 PM, A9X said:

In the real world

It was intended to be abstract.

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9 hours ago, CosmicJazz said:

So if I choose to use 1 M-73 to amplify 4 speaker's drivers using the 4 speaker's terminals (A left horn + B left tweeter / A right horn + B right tweeter), and select A AND B speakers selectors to work at same time, 

Yes, you can do that.   If you put a passive crossover filter in between the 4 amplifier outputs and 4 drivers.

7 hours ago, andyr said:

So if you take spkr wires from both A & B outputs ... you will be bi-wiring

 

Yep. That's what he said.

 

Not that the terminology in this instance is particularly important to his question .... and if anything, is only going to add confusion.

 

He has 2 amplifier inputs .... 4 amplifier outputs ... and 4 drivers.     Yes, he can drive them this way - if he puts a crossover filter in between the amps and drivers.

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Thanks guys, I think I understood.

 

(Consider passive crossover) 

 

My intention at the beginning was to use just one M-73 to bi-wire the tweeters and horns from my 3 way loudspeakers, connect the right tweeter and right horn on A right and B right, connect the left tweeter and right horn on A left and B left, and in order to all the 4 drivers works at the same time with the same input music signal, select A and B speaker's activation buttons together, to work on the same time, as you can see on the amp's front panel, it's possible for A and B be selected together. 

 

This days I was checking the price of this amp, and appears they can be found in nice condition for reasonable prices, so I'm considering purchase two, and instead of bi-wire, I will bi-amp. 

 

Appears for me this will be a great solution to power the super horn tweeters and radial horns, in class a operation, as the amp alps have a class of operation selector. 

 

But I would like to understand more, if the bi-amp solution will be in fact a huge improvement when compared with the bi-wire solution... 

 

Appreciate some thoughts, thanks guys :)

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1 hour ago, CosmicJazz said:

But I would like to understand more, if the bi-amp solution will be in fact a huge improvement when compared with the bi-wire solution... 

Using one amplifier you have 4 outputs (2 L and 2R) and 4 drivers.....    You could connect each driver to one of the 4 outputs.... with an specific passive filter in between each output and the driver.

 

Alternatively ... You could use 2x amplifiers ... .and either "bi wire" .... or just use one output for each of L and R (and do not engage the A+B button).

 

 

In short.   If you are using passive crossovers between the amp and drivers, then using a second amplifier will offer you no benefit except more power... and if these are sensitive drivers, then you likely won't make use of that.

 

 

Edited by davewantsmoore

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26 minutes ago, davewantsmoore said:

Using one amplifier you have 4 outputs (2 L and 2R) and 4 drivers.....    You could connect each driver to one of the 4 outputs.... with an specific passive filter in between each output and the driver.

 

Alternatively ... You could use 2x amplifiers ... .and either "bi wire" .... or just use one output for each of L and R (and do not engage the A+B button).

 

 

In short.   If you are using passive crossovers between the amp and drivers, then using a second amplifier will offer you no benefit except more power... and if these are sensitive drivers, then you likely won't make use of that.

 

 

 

Understood! thanks for this tip sir :)

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3 hours ago, davewantsmoore said:

Yes, you can do that.   If you put a passive crossover filter in between the 4 amplifier outputs and 4 drivers.

 

Surely, there already is a passive XO between the amps and the drivers.

 

Or did I miss that the OP's just talking about 4 drivers?

 

Andy

 

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Sorry, do not understood...

 

The application the I postes earlier is with 3 way speakers, passive crossover...

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