PSB Stratus Golds & NAD Problems

[Newfiestang50]

Hello Forum, I would like some help on my 2 channel setup which consists of PSB Stratus Gold i's driven by the new NAD C372 and C272 in bridge mode. As you guys are aware this combination of amps are producing 300 or 400 watts into each gold (depending on which part of the manual you read) which should be more than enough power to drive these speakers. My problem is not a matter of the system not being loud enough because it can play very loud, but the base, something that the Stratus Golds are supposed to do very well and is talked about alot in the review section of this site is the most unsatisfied part of my existing sound. Having said this I did recently purchase the B&W ASW675 subwoofer which does do a good job of making up for what the golds are not doing but I would still like to know if there is something not right with my setup excluding the sub. Just to be clear, I am pleased with the sound when I am using the sub but everywhere I read about the golds other owners are talking about the well definded powerful base and the ability to play very low, some even quote that you will not need a sub with this speaker, maybe my ear for base is somewhat different than everyone elses but I doubt that, I think I have a problem either with room acoustics or maybe even a speaker defect. My room is about 17ft by 19ft with a 9ft cieling, and just to cover all the little things that some of you guys may come up with, the amps are hooked up correctly ie phasing (had all my connections checked by an audio tech), the jumper strip is installed on the back of the speakers since I do not have them connected in a bi-wire configuration (tryied that also but resulted in even more lose of low end oomph since power was then reduced to 150 watts per channel). Also just to let you know, my speaker placement is probably noy ideal for acheiving max base, they are about 2 feet from the side walls and about 6 inches out from the back wall. All my connections are made with Ultralink cables and speaker wire (12 gauge). If any of you guys have these speakers or a similar problem please drop me a line to this tread with you 2 cents worth, thanks.

[Florian]

Some people also believe that there is not much info below 40Hz

powerful base and the ability to play very low

Frequency response: 36Hz-20kHz ±1dB

There is your problem, these will not play very low. Considering that you are in a normal room under normal conditions (they dont measure them in a real enviroment) you wont get that deeep bass. The speaker is not designed for that. :-)

[3db]

Hello Forum, I would like some help on my 2 channel setup which consists of PSB Stratus Gold i's driven by the new NAD C372 and C272 in bridge mode. As you guys are aware this combination of amps are producing 300 or 400 watts into each gold (depending on which part of the manual you read) which should be more than enough power to drive these speakers. My problem is not a matter of the system not being loud enough because it can play very loud, but the base, something that the Stratus Golds are supposed to do very well and is talked about alot in the review section of this site is the most unsatisfied part of my existing sound. Having said this I did recently purchase the B&W ASW675 subwoofer which does do a good job of making up for what the golds are not doing but I would still like to know if there is something not right with my setup excluding the sub. Just to be clear, I am pleased with the sound when I am using the sub but everywhere I read about the golds other owners are talking about the well definded powerful base and the ability to play very low, some even quote that you will not need a sub with this speaker, maybe my ear for base is somewhat different than everyone elses but I doubt that, I think I have a problem either with room acoustics or maybe even a speaker defect. My room is about 17ft by 19ft with a 9ft cieling, and just to cover all the little things that some of you guys may come up with, the amps are hooked up correctly ie phasing (had all my connections checked by an audio tech), the jumper strip is installed on the back of the speakers since I do not have them connected in a bi-wire configuration (tryied that also but resulted in even more lose of low end oomph since power was then reduced to 150 watts per channel). Also just to let you know, my speaker placement is probably noy ideal for acheiving max base, they are about 2 feet from the side walls and about 6 inches out from the back wall. All my connections are made with Ultralink cables and speaker wire (12 gauge). If any of you guys have these speakers or a similar problem please drop me a line to this tread with you 2 cents worth, thanks.

For music, these speakers should do very well from the specs listed;
Frequency Range

On Axis @ 0° ±1.5dB 36-20,000 Hz
On Axis @ 0° ±3dB 31-21,000 Hz
Off Axis @ 30° ±1.5dB 36-10,000 Hz
Lf Cutoff -10dB 25 Hz

Because they can go so low, maybe its a placement issue more than anything else. Sort of like trying to find a sweet spot for a subwoofer

[anamorphic96]

I would say placement.

Or try passively bi-amping your speakers instead. This should help tighten things up nicely. Especially the bass, and probably bring about a more refined sound overall.

[Newfiestang50]

What do you mean by passively bi-amp my speakers, is that the same as bridging them, that is the way they are configured as we speak.

[anamorphic96]

Use the C372 to drive the mids and highs and use the C272 to drive the lows only.

The C372 and C272 are designed to do this together. NAD or your owners manual should have some info on it.

[Pat D]

Some people also believe that there is not much info below 40Hz


Frequency response: 36Hz-20kHz ±1dB

There is your problem, these will not play very low. Considering that you are in a normal room under normal conditions (they dont measure them in a real enviroment) you wont get that deeep bass. The speaker is not designed for that. :-)

I think you had better learn more about the PSB Stratus Gold-i before making such statements. D. B. Keele reviewed it for Audio magazine some years ago (I have this at home) and found it had a very high output capability in the deep bass even down to 20 Hz. If you want to denigrate the bass response, you have truly chosen the wrong speaker!

John Atkinson measured the Stratus Gold-i's performance for Stereophile and it includes a "real world". measurement in his room--no lack of bass there even down to 20 Hz.
He does not measureme maximum output levels as Keele did.

This speaker does have a minimum impedance below 3 ohms around 100 Hz which might be an issue with a bridged NAD amp.

His room is almost square so this may cause a hefty room around 30 Hz, but below that he would get room gain. Above that, the bass response would have a number ioof peaks and dips and he probably could get a better subjective response by experimenting with speaker placement and listener position.

[Glen B]

What kind of music are you listening to ? I have owned Stratus Goldi s for a number of years. Although the Golds aren't the last word in bass extension, I listen to pipe organ recordings and find them quite adequate to the task. I also listen to other genres (pop, smooth jazz, R&B, new age, hip-hop) and the Golds perform very well with these types of music. As suggested, try experimenting with speaker placement.

[anamorphic96]

Wow I didnt know the PSB's dropped that low.

I woud definitley put the NAD's in a bi-amp mode then. Besause if im not mistaken bridge mode at 4 ohms is a no no with most amps. The other benefit of running the NAD's in a bi-amp mode would be the amps could then dip to 2 ohms and be fine.

[Newfiestang50]

Like I said in my orginal post, I do have these bridged now with no problems and I have played them very loud for long periods of time with no problems from the NADS but getting back to my orignal problem, these speakers just dont put out strong deep base like everyone has said. I have tried them with the C272 on the woofers and the C372 on the mids and tweets, the sound itself seemed exactly the same with maybe even less base than bridged since these speakers require alot of power to sound good and without bridging them with these NADS I just dont think the power is there. I have also tried an old Adcom GFA 555II on these which is supposed to be monsterious amp in its day capable of driving very hard loads, but I was very dissappointed and only kept this amp fro 2 weeks before selling it. After rethinking, I will say that it seems like these speakers once reaching a volume in my room where its starting to get loud, not over bearing but fairly loud, the mids and tweets overpower the woofer which causes you to not go higher because the sound at this point seems to be getting harsh. I know that what i am about to say is not normally done but it almost seems like i need a much more powerful amp on the woofers than i have on the highs, can this be done?

[Florian]

I am not picking on a speaker, but i would recommend this. Set them up in a non square room using a Krell or Mark Levinson or some powerfull solid state amp and run a 20 and 30Hz test tone on it and report back. I am betting that it wont do it audible. Not that that is bad, but give it a try. Worst thing that happens is that i am proven wrong. Its like someone posting that his speaker does 20Hz but is 10db down Even SpankingVanillas speakers do 20Hz, but will you feel it on a normal level?

PS: 3ohms is not a bad load and this is EXACTLY what i posted many times about the impedance swings and why Apogees are much easier on the amp than some others. But typically noone listend, but this is exactly why i dont buy noormal commercial amps rated highly in reviews.

[Florian]

The next thing is that he will use two amps with different gain and has to adjust again. Might as well drive them actively and junk the internal crossover or use passive volume controls to set the gain and match them. But then you get a complex setup and will loose signal clarity along the way and have to rebuild the speakers. And a square room is unfortuante which is why you might want to get some room acoustics. My tip, junk the NAD's and buy a new power SS amp used on audiogon and spend the rest on room acoustics.

-Flo

PS: Acording to my info the NAD is internally bridged just like the $9K ampzilla monos i have here and they dont drive a 4ohm load correctly either. When your speaker drops to 3ohms the amp sees a 1.5ohm load internally and clips.

[anamorphic96]

Actually Florian the NAD amps are gain matched. NAD has set these up to work together being they use identical amp sections.

[Florian]

Actually Florian the NAD amps are gain matched. NAD has set these up to work together being they use identical amp sections.

That is very good then, use them in the biamping configuration or try a powerfull SS from Krell or Mark Levinson. The older stuff tough.

[3db]

I am not picking on a speaker, but i would recommend this. Set them up in a non square room using a Krell or Mark Levinson or some powerfull solid state amp and run a 20 and 30Hz test tone on it and report back. I am betting that it wont do it audible. Not that that is bad, but give it a try. Worst thing that happens is that i am proven wrong. Its like someone posting that his speaker does 20Hz but is 10db down Even SpankingVanillas speakers do 20Hz, but will you feel it on a normal level?

PS: 3ohms is not a bad load and this is EXACTLY what i posted many times about the impedance swings and why Apogees are much easier on the amp than some others. But typically noone listend, but this is exactly why i dont buy noormal commercial amps rated highly in reviews.

this with dual 5 1/2" woofers,. I used my rat shack meter and a computer generated sinewave with a frequwncy of 30 Hz so I'm not surpised at all that the Goldi will hit 20Hz.

[Florian]

Now come on you know that doesnt count for nothing. Lets do this,

1. Buy a microphone
2. Install the free software from AudioNet
3. Use the RatShack meter and set the system to 75db at 4m distance off axis
4. Run a 15Hz to 30Hz sweep at unchanged volume
5. Publish the measurements



PS: Then we do the same at 85db and then 90db

[3db]

Now come on you know that doesnt count for nothing. Lets do this,

1. Buy a microphone
2. Install the free software from AudioNet
3. Use the RatShack meter and set the system to 75db at 4m distance off axis
4. Run a 15Hz to 30Hz sweep at unchanged volume
5. Publish the measurements

My speakers in room bass response

[Florian]

My speakers in room bass response

I am talking about a real measurment. Some thing like this.. Its quite easy..

The drop off at the 5khz is normal on the laptop soundcards and the bass raise is partially from the unabsorbed backwave of the dipol bass radiation pattern and the rest is room gain. These were taken at 85db

[3db]

I am talking about a real measurment. Some thing like this.. Its quite easy..

The drop off at the 5khz is normal on the laptop soundcards and the bass raise is partially from the unabsorbed backwave of the dipol bass radiation pattern and the rest is room gain. These were taken at 85db

The Rat Shack meter are real measurements,. If anything, its insensitive to the lower frequencies so I have to add about 3 to 4 db at around 30 Hz. Still don't see what I'm doing wrong.

[Florian]

Well in case you change your mind go and buy a microphone and download the software and see what it really does. Will be interesting :-)

[Newfiestang50]

Well guys no need to buy any new software or anything else. I took your other advice and started playing around with placement, all I can say is that now i understand what all the reviews said about the golds. Basically i moved some furnture around in the room and got each speaker alot closer to each of the adjacent corners, placed in one of my favorite tunes and finally heard the Golds for the first time and managed to listen to them for two hours with no sub turned on and just smileing. The speakers are now about 18ft apart, angled slightly in to my listing chair and the soundstage is enormous, these things do play alot lower than i ever thought possible with just a 10 inch base driver. Now i just have to find a new place in the room for my sub retune it for a lower cutoff freq and things should be good. Thanks alot guys I never thought placement of a speaker could make such a positive change in my setup. Thanks again.

[Pat D]

I am not picking on a speaker, but i would recommend this. Set them up in a non square room using a Krell or Mark Levinson or some powerfull solid state amp and run a 20 and 30Hz test tone on it and report back. I am betting that it wont do it audible. Not that that is bad, but give it a try. Worst thing that happens is that i am proven wrong. Its like someone posting that his speaker does 20Hz but is 10db down Even SpankingVanillas speakers do 20Hz, but will you feel it on a normal level?

PS: 3ohms is not a bad load and this is EXACTLY what i posted many times about the impedance swings and why Apogees are much easier on the amp than some others. But typically noone listend, but this is exactly why i dont buy noormal commercial amps rated highly in reviews.

Bass response in an anechoic environment is not the same as response in a room. Below the fundamental resonance of the room, there is the phenomenon of room gain at about 12 dB per octave. You read the specs but you don't understand what they mean.

Besides, you didn't bother to look up the measurements John Atkinson did in Stereophile.

http://stereophile.com/floorloudspea...04/index8.html

In John Atkinson's room, you can see the bass is down very little at 20 Hz. Atkinson does not attempt to measure the maximum output from speaker but D. B. Keele does, and his review in Audio magazine showed that the Stratus Gold-i is capable of quite substantial output even at 20 Hz . I have that review at home.

[Pat D]

The Rat Shack meter are real measurements,. If anything, its insensitive to the lower frequencies so I have to add about 3 to 4 db at around 30 Hz. Still don't see what I'm doing wrong.

You're not!

[Pat D]

Well guys no need to buy any new software or anything else. I took your other advice and started playing around with placement, all I can say is that now i understand what all the reviews said about the golds. Basically i moved some furnture around in the room and got each speaker alot closer to each of the adjacent corners, placed in one of my favorite tunes and finally heard the Golds for the first time and managed to listen to them for two hours with no sub turned on and just smileing. The speakers are now about 18ft apart, angled slightly in to my listing chair and the soundstage is enormous, these things do play alot lower than i ever thought possible with just a 10 inch base driver. Now i just have to find a new place in the room for my sub retune it for a lower cutoff freq and things should be good. Thanks alot guys I never thought placement of a speaker could make such a positive change in my setup. Thanks again.

LOL. That's one of the things you find out quickly when you get speakers which can reproduce the deep bass! Join the club. The Stratus Gold-i is a very fine speaker. Enjoy.

The 10" bass driver is also augmented by the port, whose influence can be seen in Fig. 3 of John Atkinson's measurements.

http://stereophile.com/floorloudspea...04/index8.html

[Glen B]

Well guys no need to buy any new software or anything else. I took your other advice and started playing around with placement, all I can say is that now i understand what all the reviews said about the golds. Basically i moved some furnture around in the room and got each speaker alot closer to each of the adjacent corners, placed in one of my favorite tunes and finally heard the Golds for the first time and managed to listen to them for two hours with no sub turned on and just smileing. The speakers are now about 18ft apart, angled slightly in to my listing chair and the soundstage is enormous, these things do play alot lower than i ever thought possible with just a 10 inch base driver. Now i just have to find a new place in the room for my sub retune it for a lower cutoff freq and things should be good. Thanks alot guys I never thought placement of a speaker could make such a positive change in my setup. Thanks again.

Good for you. Enjoy.