AU-555 Crossover Question

[bluemando]

Hi... I'm posting this again under a different title because I'm desparate for an answer to my question. Apologies to those who weren't interested the first time around. Here it is:

I'm using bookshelf speakers that goes down to 50 hz and considering a sub so that I can go down to 30 hertz (or more. I'm considering the Pinnacle AC Sub 100. This review ( http://tinyurl.com/58qqje ) states that the Pinnacle doesn't have a variable crossover circuit, so it can't perform at its best unless it's connected to a source that has a crossover-frequency. Frankly, I don't know how to determine that for my AU-555. I don't have the manual, nor do I know of any indicators, if there are any, that would give me a clue about that. I suspect it doesn't have a crossover-frequency, but I thought I'd check w/ the experts before moving on to other possibilities. The Pinnical sub interests me because of its comparatively small foot print compared to other subs. H=14 1/2" W=13" D=14 5/16" (with Amp & Grille)

Thanks

 

[ferninando]

amps don't have built in crossovers. you must build a passive custom one or buy a electronic one with the xovr freqs you need.
however the au555 I'm sure will go down to 20hz with no prob. so you may not need a xover. just run a separate wire to the sub.

 

[bluemando]

amps don't have built in crossovers. you must build a passive custom one or buy a electronic one with the xovr freqs you need.
however the au555 I'm sure will go down to 20hz with no prob. so you may not need a xover. just run a separate wire to the sub.

:saywhat: See, I've never used a subwoofer. My common sense tells me (don't laugh, now) that the hook-up is simplying connecting speaker wire from the AU-555 speaker connectors, to the sub (which I presume has left and right connectors for that wire) and then send wire from out of the sub to speakers. Where does a 'seperate wire' come from on the sub and what does it connect to on the speaker? Sorry I'm soooo not with it. But hey, thanks for trying to help. I was beginning to think nobody cared

 

[hifi_nut]

The linked review states clearly the review model was kind of special for magazine reviewers that tend to use such units with line level outputs from their pre-amps, but, and I quote:

Pinnacle has since added a variable low-pass filter (50 to 150 Hz) and an LED that shines red when the sub is powered on, but there are still no speaker-level inputs on this sub.

Thus, you must have only a variable output line from the pre to the sub input. A fixed levell line out ( like a tape-out ) won´t work because it is fixed.

The main speakers will still receive the full range signal from the amp, so the system as a whole may prove a little finnicky to balance properly.

Jorge

 

[bluemando]

The linked review states clearly the review model was kind of special for magazine reviewers that tend to use such units with line level outputs from their pre-amps, but, and I quote:

Pinnacle has since added a variable low-pass filter (50 to 150 Hz) and an LED that shines red when the sub is powered on, but there are still no speaker-level inputs on this sub.

Thus, you must have only a variable output line from the pre to the sub input. A fixed levell line out ( like a tape-out ) won´t work because it is fixed.

The main speakers will still receive the full range signal from the amp, so the system as a whole may prove a little finnicky to balance properly.

Jorge

As usual I'm confused. Are the inputs on the back of my Sansui AU-555 ( Tape, phono, aux) all fixed. Obviously, I don't understand the distinction between fixed and variable. Does the AU-555 have variable line input/outputs or are they all fixed?

Also, my understanding is that if the Pinnacle has speaker-level inputs; so, in my mind at least) all I need to do is connect the integrate amp's left and right channels to the sub's lft and rt channels.

Anyone know of any other SMALL [for example: 14.5" (H) x 19" (W) X 16" (D) OR LESS] subs under $300 (I'd go for "< $400," if I was convinced it was worth the difference)

Many Thanks f/m
"The Confused Guy"

 

[hifi_nut]

Bluemando,

Don´t worry about your being confused, that makes two of us. Just look at my signature.

Ok., back on topic.

At the back of your Sansui you will find both inputs ( to accept the signals from your sources like a turntable, a tuner, a CD player, a cassette player, etc.) and outputs ( speaker posts that send the signal to your speakers, and a fixed line levell tape output that routes signals from your sources to your tape recorder to do just that, record those signals.

Now, in some cases, amplifiers will have pre-amplifier outputs to allow the pre-amp section to drive a different power amplifier, or to drive more than one amplifier at the same time.

The difference between a tape out and a pre-out is that the former has a fixed levell ( not affected by your volume control knob ) whereas the former has a variable levell output controled by the volume pot.

The problem with the Pinnacle sub-woofer you mention is that you won´t be able to drive it with your Sansui because, on the one hand your amp doesn´t have a variable levell pre-amp output, and, on the other hand the sub only accepts this kind of driving and not speaker levell driving.

Do not, at any rate, try to drive the line input in the Pinnacle sub with the signal from the speaker posts at the back of your amp, which have a much higher output voltage, resulting not only in unbearable distortion, but very likely a blown sub-woofer amplifier / driver too.

You really do need either a sub that takes speaker level signals or an amplifier with a pre-out set of jacks.

Hope you´re just a little less confused.

Don´t worry about asking questions untill you got them all answered and everything is cristal clear in your mind, that´s what we´re here for.:thmbsp:

Let us know what you decide.

Jorge

 

[Robisme]

The AU-555 does have preamp out.:yes:

Rob

 

[hifi_nut]

The AU-555 does have preamp out.:yes:

Rob

Thanks robisme.:thmbsp:

In that case the Pinnacle sub can be driven by the Sansui pre-amp section. All it takes is a "Y" splitter at the pre-outs and one pair of interconnects driving the sub, another going to the power-in of the 555.

 

[Aage]

Well, there you go: connect the Y-jacks (2-male RCA to 1-female RCA, one per channel) output to give the line-level signal to the sub, put the other male jack back into the MAIN IN of the AU-555, then play it all as usual.

I notice the article mentions that there is a level control (volume) for the subs, so one can adjust the overall balance of loudness between the sub and regular speakers.

Should be real nice, the writ-up on the sub got me interested too.

Please post your results once you have it all going?

 

[NeilT]

Hi again Bluemando,

I seem to recall that in your original posting the problem was that your AU-555 was distorting ("clipping" you said) at the sort of levels you wanted to be occasionally listening to and that you wanted a Sub to take over some of the work.

The only way you'll get that to happen is if you get the AU-555 main amp to handle a filtered output. You can use either an Active Crossover or the type of Sub which will feed a filtered output back to the AU-555 main-amp.

With using Y plugs you'll just be duplicating the output and leaving the AU-555 to still have to handle the full frequency range i.e more clipping and distortion.

- Neil.

 

[ferninando]

subs don't necessarily eliminate clipping. the amp is still driving a set of spkrs and clipping in the process. a sub MAY only add to the problem. the amp may be underpowered for your listening tastes..

PS: the au555 is only 25 watts rms power. a weakling. get a bigger amp. eliminate clipping with no sub.

 

[bluemando]

Bluemando, Don´t worry about your being confused <snip> At the back of your Sansui you will find both inputs ( to accept the signals from your sources like a turntable, a tuner, a CD player, a cassette player, etc.) and outputs ( speaker posts that send the signal to your speakers, and a fixed line levell tape output that routes signals from your sources to your tape recorder to do just that, record those signals.

Now, in some cases, amplifiers will have pre-amplifier outputs to allow the pre-amp section to drive a different power amplifier, or to drive more than one amplifier at the same time.

The difference between a tape out and a pre-out is that the former has a fixed levell ( not affected by your volume control knob ) whereas the former has a variable levell output controled by the volume pot <snip> You really do need either a sub that takes speaker level signals or an amplifier with a pre-out set of jacks. Hope you´re just a little less confused.

Don´t worry about asking questions untill you got them all answered and everything is cristal clear in your mind, that´s what we´re here for.:thmbsp:
Let us know what you decide. Jorge

Jorge, your post helped get me to get a little bit better handle on this stuff. It's an ongoing process for me. A few weeks ago people posted advice to and usually I han't a clue what they were talking about. Mostly I didn't understand the terminolgy. I spent precious time Googling the terms but, all too often, the terms were used by those who already new the lingo, so their was no explaining.

I surmise that a subwoofer that has connections at "speaker level," are those that have connectors for speaker wire.

To connect a subwoofer to an integrated amp or receiver "at line level" one needs 1) a cable with RCA plugs at the ends of it, 2) an amp that has "plug-in-connectors" (would "inputs" be the correct term for that?) 3) A subwoofer that has "sub-in" connectors (again would "inputs" be the term to use here?) The two units would be "patched" together via the subwoofer preout or, as in the case of my Sansui AU-555, a preamp out. As Rob noted, my Sansui does have a preamp-out. Bottom line is that the Pinnacle would work with my Sansui becase both sub and amp are speaker and line level capable. However it's all moot at this point because, as Neil pointed out, said connection-methods would result in draining the power of my already low powered amp. See my message to Neil. And
Thank you!

NOTE To Aage: I suspect that I won't be getting the Pinnacle sub; so, I won't be reporting back about it. I would have been happy to do that though, had I bought the sub. See my message to Neil.

blue

 

[bluemando]

Neil, you saved me some agravation

Hi again Bluemando,
I seem to recall that in your original posting the problem was that your AU-555 was distorting ("clipping" you said) at the sort of levels you wanted to be occasionally listening to and that you wanted a Sub to take over some of the work.

Right you are Neil! And I confess I had forgotten about that. After reading your post and some others (back then) I had given up on the idea of using a sub and so I started looking at full range speakers. I auditioned a used pair of B&W 603s and a Vandersteen 1c. Both speakers sound pretty good, considering a pretty bad auditioning area. Given the low price of the Vandy came out a winner. Problem is that it's not an easy speaker to drive (initially, I didn't know that) so I ruled it out. Latter, I re-thought my situation again, taking into consideration how good my KEF speakers usually sound; how they are quite attractive-looking on their silver stands; and, that they leave a small footprint in my small living room. So, I came full circle to considering a subwoofer... again. Only I forgot why I had reject the idea in the first place. Yeh... I'm getting old, darn it.

The only way you'll get that to happen is if you get the AU-555 main amp to handle a filtered output. You can use either an Active Crossover...

I don't want a filter out put cluttering up the area. As for "Active Crossover," I don't want to deal with having someone do that for me... nor would I attempt to do it myself via an electronic one w/ a the crossover that's suitable ( thanks for that bit of info oldhiguy)

or the type of Sub which will feed a filtered output back to the AU-555 main-amp.

That would be an expensive-type sub, right?

With using Y plugs you'll just be duplicating the output and leaving the AU-555 to still have to handle the full frequency range i.e more clipping and distortion. - Neil.

Thanks for reminding me about that Neil. I really appreciate that you stopped me from making a mistake.

blue

 

[bluemando]

Argh!!

subs don't necessarily eliminate clipping. the amp is still driving a set of spkrs and clipping in the process. a sub MAY only add to the problem. the amp may be underpowered for your listening tastes..

PS: the au555 is only 25 watts rms power. a weakling. get a bigger amp. eliminate clipping with no sub.

It's amazing anyone ever bothers with getting a subwoofer. You either have to be lucky in your choice or an electrical engineer that knows all the positives & negatives. Well, I suppose I'm exagerating, but you know what I mean.

Thanks
blue

 

[ferninando]

luck and being a EE has nothing to do with it. Experience and understanding of the underlying electronics principles governing how these audio thingys work goes a long way toward making wise choices when purchasing good audio equipment that you'll be happy with. Trial and error, listening before buying, learning about the thing you're interested in will help alot. Time was you could go into a respectable stereo store and you could pik the sales peoples brains as what was good and not so good. those days are gone. Weither it's new or vintage, we audio enthusiasts are pretty much on our own when it comes to choosing what to buy. thank god I'm an "old hifi guy" and can make up my own mind.

 

[bluemando]

Well on one account I have to disagree with you. People do get lucky, whether it be in hi-fi choices or whatever. Everything else you say seems correct to me.... The thing that I don't understand is that if a subwoofer has its own amplifier (active sub???) and my Sansui works well with the KEF speakers, except for bass notes under 50 hertz (then) why should adding a *powered* sub burdon the (low powered) integrated amp?

Thanks
blue

 

[NeilT]

why should adding a *powered* sub burdon the (low powered) integrated amp?

Thanks
blue

It won't burden the amp any more than it already is being burdened - you say it doesn't do low frequencies well at high volumes - well that won't change with Y plugs - it'll just send the same frequencies to both the Sub and your Sansui's main amp. To stop the distortion you need to stop sending those lower frequencies out of your Sansui's Pre-amp to the Main amp. You can only do that with an Active crossover or a Sub which has a High-pass Filter outlet.

- Neil

 

[Stene]

Matching Active Crossover to AU-555. Not for bass frequencies.
200Hz, 340Hz, 560Hz, 900Hz, 2way-High, 2way-Low,
2.5kHz、3.6kHz、5kHz、7kHz 2.5kHz, 3.6kHz, 5kHz, 7kHz

 

[NeilT]

Wow Stene!

You can certainly pull them out of the hat!!

I've never seen anything like that from Sansui before.

- Neil.

 

[Stene]

Wow Stene!

You can certainly pull them out of the hat!!

I've never seen anything like that from Sansui before.

- Neil.

Hi Neil. CD5 don't have low frequency output.
This filter is a little bit better
F1: 60、75、95、120、150、190、 60,75,95,120,150,190,
240、300、380、480、600Hz 240,300,380,480,600 Hz

F2： F2: 300、380、480、600、750、950、 300,380,480,600,750,950,
1.2k、1.5k、1.9k、2.4k、3kHz 1.2k, 1.5k, 1.9k, 2.4k, 3kHz

F3： F3: 1.5k、1.9k、2.4k、3k、3.8k、4.8k、 1.5k, 1.9k, 2.4k, 3k, 3.8k, 4.8k,
6k、7.5k、9.5k、12k、15kHz 6k, 7.5k, 9.5k, 12k, 15kHz