improving SRS Bass

Schurkey

inspiredsports wrote: »

You've spent hours writing a book here, and I'm not quite sure why.

You are preaching to the choir as 99.9% of the folks who frequent CP get it.

Now, as we are trying to help turbo' in Peoria, has he checked back in yet ??

Just one of the many services I offer...

I see the issue over and over. People assume that high power means better sound quality.

F1nut wrote: »

Perhaps you missed it....I'm sure you did.....the OP is using a different amp on the SRS's than he is on the 1C's.

Yup. I still don't see where he says it's a different amp...

F1nut wrote: »

What's up with the vrooom3440 quotes? DK happens to be a highly respected, well liked and very knowledgeable forum member who's thoughts on this matter are spot on. I cannot say the same for yours.

I'm no longer able to edit my previous post; my apologies for the incorrect author attributed to the quotes. I do not know how that happened, but it's obviously my fault. I have nothing against either (or any) forum member; and if you don't like my advice...Ok.

F1nut

Schurkey wrote: »

Yup. I still don't see where he says it's a different amp...

"2CH: SDA SRS (new caps) with NAD 541I, NAD 917 and modded Phase 400 (soon to be NAD 208)

HT: SDA 1C (new caps, SL2500s, bass mod) with NAD T763 and Monitor 4 as surround"

I'm still waiting to hear what the bass mod is.

DarqueKnight

Schurkey wrote: »

I would have said that high QUALITY has VERY LITTLE to do with high POWER; providing that the amp has "enough" power to achieve the volume desired.

Actually, I and most people who regularly post on this forum, thoroughly understand this concept. You must have overlooked or misunderstood this:

DarqueKnight wrote: »

Many people simply don't understand that the reason for high quality, high power amps is not for playing LOUD, it is for playing with more ACCURACY.

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Schurkey wrote: »

I would have said that high QUALITY has VERY LITTLE to do with high POWER; providing that the amp has "enough" power to achieve the volume desired.

I see that you have reading comprehension problems. I never said that high power=high quality. I understand that just as I understand that high horsepower does not equate to a quality automobile engine. I was talking about high quality amps with high power.

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DarqueKnight wrote: »

Music is full of transients that often require very brief huge increases in power to reproduce accurately. If these transients are clipped, a corresponding amount of realism is subtracted from the music. High power amps have huge RESERVES of power and are more capable of accommodating transient power demands.

Schurkey wrote: »

What you're describing was once--and perhaps still is--considered "dynamic" power; which may or may not be related to the FTC-rated power of the amp. Seems to me the amps with "loose" power supplies tended to have better "dynamic" power in relation to the "FTC rated" power; and the amps with "stiff" power supplies tended to have conservative dynamic power in relation to the rated power--but I won't swear to that.

No. You just don't get it. I wasn't referring to dynamic power at all, which is "short" term power. Dynamic power represents a strain on an amp. I was referring to RESERVE POWER WHICH CAN BE DELIVERED CONTINUOUSLY AND COMFORTABLY BY AN AMPLIFIER.

Look at it this way: Consider two automobiles, car #1 with a top speed of 80 mph and car #2 with a top speed of 200 mph. Both cars can cruise comfortably at 40 mph. However if both cars were suddenly called upon to run at 80 mph, car #1 could do it, but it wouldn't be able to do it too long nor do it too often. A speed of 80 mph represents the dynamic, or peak speed of car #1. The 200 mph car can cruise at 80 mph all day long (CONTINUOUSLY) because this 80 mph is well within its performance "comfort zone".

===================================

DarqueKnight wrote: »

As I have gone up in amplifier power, I did not increase my sound levels for listening. Although my sound levels did not increase, my sound stage size, image weight, detail, bass power and realism did increase.

Schurkey wrote: »

I suggest that it was a coincidence: As you went up in power, you coincidentally went up in QUALITY/ACCURACY. You're hearing the "quality" improvement, but attributing it to the increased power.

In short: I'm trying to get you to understand that quality of output power and quantity of output power are not the same;

I never said that it was. You wrote a whole dissertation about something that I never said or even remotely implied. Furthermore, I would never say something so ridiculous as "high power=high quality". Thanks anyway for the "lesson". I look forward to hearing from you in the future when you actually know what you are spouting off at the keyboard about.

Schurkey wrote: »

But what the hell do I know?

Very little...apparently...about audio in general and audio electronics in particular. Stick around. There's lots of knowledgeable, friendly folks around for you to learn from.;)

DarqueKnight

turbopantera wrote: »

Has anyone noticed a lack of low frequency bass in the SRS has anyone made any improvements.

No. Quite the opposite.

I currently own SRS's and I have owned two pairs of 1C's. I assure you that, in an appropriately sized room, the 1C's bass is no match for the SRS's. In smaller rooms, the 1C will be a better match.

turbopantera wrote: »

The floor is carpet and using the flat feet. Perhps the spikes would help, but the 1Cs dont have any spikes and they sit on carpet also. Now dont get me wrong, the SRSs have really good tight bass right down to about 28 hz. But the 1Cs go even lower to 20hz and below. I notice this because I have several pieces of music that have passages where you FEEL the bass more than you hear it. It is played on the 1Cs and not on the SRSs. Perhaps I just have an abnormal set if 1Cs. I have made a slight wiring change to the drivers in the 1C and that might of increased their bass beyond what was original.

The larger SDA's produce more low frequency energy and have a greater need for bracing and a solid footing than the smaller SDA's. In addition to this, the SRS's larger passive radiator and greater number of drivers push more air. If the SRS's are not braced properly, some of the force exerted by the drivers will be against the speaker cabinets, rather than the air in front of the cabinets. This will negatively impact the SRS's bass response. I think that your SRS's may be "wobbling" due to the instability of the carpet under them. Try spiking them.

The lower 3 dB limit of the 1C is 35 Hz, so getting significant response out of them at 20 Hz is unlikely unless there is some room excitation and/or cabinet resonance going on.

DarqueKnight

F1nut wrote: »

I'm still waiting to hear what the bass mod is.

I'm hoping it was not replacing the passive radiator with an active driver.:)

Conradicles

turbopantera wrote: »

I have made a slight wiring change to the drivers in the 1C

Please tell. That is interesting.

turbopantera

Gee, what did I start?

I must let everyone know that I do understand the basic principles of hifi. I am an electrical engineer and have experimented with audio and electronics for 30 years. I have even designed some of my own stuff. I can tell you that any amp I am using is a Quality piece. I have amps with good sound from 50 watt to 270 watts. I have done a lot of experimenting and collecting over the years. The 1Cs are in the HT room where primary amp is an NAD T763 but some times connected to a Sansui G9000. The SRSs are connected to a modded Phase 400. I added bigger filter caps, reworked the circuit board with better signal caps and replaced the outputs with 2SD555. It has enough power to easily bottom out the voice coils of the 1Cs against the magnets with a loud pop and can even "PoP" the SRS before it goes into clipping with a good bass drum hit. And before you say something, Yes, I know this can damage the drivers, but it only happens on accident when I am in a loud mood. Hey, some songs you just have to turn up. Under normal play, the meters on the Phase barely move. I have also had the G9000 connected to the SRSs with the same results. Next week I will be taking delivery of an NAD 208THX amp that is rated to a 2 ohm load. I am sure it wont have any problems even if the Phase does.

The two rooms are similar size as one is directly above the other. The only real difference is the 2 ch room has a cathedral ceiling and the HT room has a flat ceiling and concrete floor that is carpeted. But I have had the 1Cs in other rooms and the musical result is the same. I never seem to notice any cancelation spots in the room or even th rest of the house, but I do notice some room increases in areas like the top of the stairway and the wine cellar.

I have tested both speakers and systems using a sinewave signal generator. With the SG, I can select any frequency I want and measure/listen to results. As I said, both systems have good bass at low and high volume. It is just that the 1Cs go lower. I am suprised to see the -3db point of each speaker, and dont believe it. They both seem to go much lower. I really need a good sound pressure meter to test with. I played a 20 hz note through the 1Cs and the lights on the ceiling fan started to rattle so I know the sound wave was coupling within the room.

The one song I really notice the lack of bass in is Dire Straits Iron Hand. It is the 8th song on the On Every Street album. The bass note in particular is at 1:57. This is a great song, in fact the whole album is a masterpiece. A couple other favorites for bass are David Arkenstone - In the Wake of the Wind, and Lincoln Mayorga - Missing Link

As for the mod of the 1Cs, as I mentioned earlier, I was bottoming out the voice coils of the drivers. Hey, Skynard just has to be loud. To resolve this, I changed the dimentional drivers from a parallel connection to series. As a side benefit, the bass got deeper. Anyone else care to try the same mod and validate my results?

I know all of my drivers are good and I know there is no bad coil connection, been there, done that.

I really enjoy the overall sound of the SRSs better than the 1Cs, I just want the same deep bass. If you are in the Peoria area, you are welcome to experience this first hand.

Face

Your ears should start to bleed before those drivers bottom out. I'm not familiar with your particular PL, but others I've seen were only rated for 8ohm operation.

DarqueKnight

I'm outta here. Good luck.

turbopantera

The PL 400 was one of the original designs of Bob Carver before he started a company under his own company. It is a 200 wpc amp. 6 outputs per side. It might of had an 8 ohm rating at one time, but not now. With proper mods, it can hit 900w into 2 ohms. (http://synthetizer-sche.chez-alice.fr/power%20ampli/phase%20linear/repair.htm) It hits pretty hard. It may not be a new high dollar amp, but hey, the SDAs are pretty old their selves and some of the latae 70s and early 80s equipment was pretty good.

F1nut

It has enough power to easily bottom out the voice coils of the 1Cs against the magnets with a loud pop and can even "PoP" the SRS before it goes into clipping with a good bass drum hit.

That's not power, that's a total lack of driver control.

I changed the dimentional drivers from a parallel connection to series. As a side benefit, the bass got deeper. Anyone else care to try the same mod and validate my results?

Wow and absolutely not.



As stated, good luck.

heiney9

Agree with F1, you have a lack of power or current if you are bottoming/popping the drivers. When Stereo Review first tested the SRS's they used the most powerful amp available at that time and the SRS's absorbed over 1000 wpc before the amp gave up................they never popped the drivers or bottomed them out or heard/measured and stress or break-up with the drivers. They said the SRS's could have taken more except that was the most powerful amp available at the time.

What you did to the 1C's really no longer makes them SDA's.

Good luck with your semi-Franken Polk.

H9

TroyD

I love Bob Carver and all that...but the Flame Linear 400 is/was/always will be a **** amp.

BDT

vmaxer

F1nut wrote: »

That's not power, that's a total lack of driver control.



Wow and absolutely not.



As stated, good luck.

F1, I am using a Sunfire 405 X 5 to run my 1.2 TL's. When I push too hard my drivers will pop.:o When you state driver control I'm not sure what you mean. Can you explain?? I am not disagreeing, just not very experienced and don't understand. What would be a better amp that won't break the bank. I have also used an Adcom GFA 555 with the same results.

Thanks a lot!!

concealer404

Would this possibly be someone else that is in need of the Dreadnaught?



Actually, the more i think about this, the more interesting it is to me. I know nothing about the amp in question, so i don't know if it's common ground or not or all that jazz, but it seems that it should be a lot stronger than my Oinker, right?

When Nik had my amp on his 1.2TLs, there was never any popping, it just got louder and louder and still sounded decent until the amp finally went into protection mode. No popping, no audible weirdness at all. The point where the amp went into protection mode was so loud that you'd have to be halfway insane to want to even listen to ANYTHING at that volume.

ASSUMING that the amp is useable with the SRS without the A1-1, either someone is trying to play entirely too loud, or i think something is broken.

Or the amp could just be that bad. Like i said, i have NO knowledge on this amp at all, it just seems like it should be way stronger than what i'm using.

heiney9

vmaxer wrote: »

F1, I am using a Sunfire 405 X 5 to run my 1.2 TL's. When I push too hard my drivers will pop.:o When you state driver control I'm not sure what you mean. Can you explain?? I am not disagreeing, just not very experienced and don't understand. What would be a better amp that won't break the bank. I have also used an Adcom GFA 555 with the same results.

Thanks a lot!!

You have a 5 channel amp basically drawing power from a single transformer......not really ideal.

Bottom line is almost every amp runs out of current or power (regardless of the manufacturer rating) so every amp if you push it hard enough will clip and pop drivers, until you use an uber-ultra high end amp.


I run a 30wpc amp and it plays cleaner, louder and has more control than my previous 125wpc amp. Ultimately it won't win an SPL contest but it plays louder than my ears can take, a solid 92-95db, so I don't care it's only rated at 30wpc. It's all in the design, parts and the fact it's an outstandingly musical amp.

H9

vmaxer

F1nut wrote: »

That's not power, that's a total lack of driver control.



Wow and absolutely not.



As stated, good luck.

heiney9 wrote: »

You have a 5 channel amp basically drawing power from a single transformer......not really ideal.

Bottom line is almost every amp runs out of current or power (regardless of the manufacturer rating) so every amp if you push it hard enough will clip and pop drivers, until you use an uber-ultra high end amp.


I run a 30wpc amp and it plays cleaner, louder and has more control than my previous 125wpc amp. Ultimately it won't win an SPL contest but it plays louder than my ears can take, a solid 92-95db, so I don't care it's only rated at 30wpc. It's all in the design, parts and the fact it's an outstandingly musical amp.

H9

Thanks for the reply, but F1 said it wasn't lack of power but was lack of driver control... This is a bit confusing to me. I do push the speakers at times and they are in a room that is open to the rest of the house and the ceiling is 18 feet (open to upstairs)

turbopantera

It is possible the pop is caused by the amp as it nears clipping. But it only happens on specific songs and on specific kick drum hits. I understand that many people dont like the PL. I have heard it all before in other places so go ahead and complain. It has been very reilable and has a very open sound at medium volume levevls. And yes, I know how the PL got its nick name. They burnt up when many bands used them as PA amps. The origional outputs were weak. Thus the reason for the mods I did. In fact, it was toasted when I bought it back in college. However, it must of not sounded too bad, as many studios used them. Either way, next week the "Flame"Linear will be replaced by an NAD 208 FET amp so I will have to play the same music and find out. Though I must say, I have never burnt out a tweeter or driver coil, so the signal must not be too dirty.

Heiney9, I disagre that the change I made no longer makes the 1Cs an SDA nor does it make them a franken polk (though the SL2500s might). The entire SDA array is still hooked up and functioning and it asctually seemed to enhance the effect of the array. All what was done was a change of the way each driver was connected. It was simply a similar change to what polk did to the main drivers as they went from the 1B to 1C. In the 1B both the main drivers and dimentional array, both drivers were wired in parallel. In the 1C, the Bass drivers were wired in series, and the dimentional array in Parallel. I simply made the Dimentional drivers match. It slightly raised the speaker impedence and slightly altered the speakers overall Qts number. Changes in any Thiel small parameters can effect the lower system 3db point. I wish I know all the Thiel smalls for the drivers and passive radiator. Then I could model the system in Bass Box Pro and be able to analyze the specific effect. In fact, if I had the Theil smalls for the SRS componets, I could model it and verify for sure the bass response and do theoretical changes including different model drivers and different wiring configurations. I do have a woofer testing device that will read the theil smalls of the drivers if I remove them, but I have no way of getting the PR specs. Like I said, I am an engineer, I love to tinker. My tinkering with woofer configuration is no different than someone "Rolling" tubes to get a different sound.

As for my Bass response, I am betting on two things. One, the cabinet might need a little better sealing, and two, I belive the room is too small. I have the speakers on the long wall of a rectangular room with a cathedral ceiling. I need to move them to the garage which is bigger and open just for a test, however the garage is a very "live" room. I just want them to play that note in Dire Straits - Iron Hand. I need to put that song on the oscilloscope and measure the actual frequency of it.

snow

vmaxer wrote: »

F1, I am using a Sunfire 405 X 5 to run my 1.2 TL's. When I push too hard my drivers will pop.:o When you state driver control I'm not sure what you mean. Can you explain?? I am not disagreeing, just not very experienced and don't understand. What would be a better amp that won't break the bank. I have also used an Adcom GFA 555 with the same results.

Thanks a lot!!

Hmmm..... considering that your 1.2TL's are an easy load to drive compared to the original SRS 8 ohms vs 4 ohms unless the caps in the amp are getting tired or some other problem with the amp is occuring your ears should give out before the amp does unless your living in a gymnasium. You should be well over 115 DB before the amp starts to clip which for most sane humans is more than loud enough.

If you were driving the original SRS I would suggest the Sunfire 300 X 2 it is capable of driving very low impedance loads far easier than any of the other Sunfire amps 405 x 5 or 7 or the 600 x 2.





REGARDS SNOW

OldmanSRS

Turbopantera,
IMO you should have introduced your post with the detailed information on your background and all the testing you did up to now. It would have narrowed the scope of the discussion.

The fact that it sounds better to you now is more interesting to me than the lack of bass issue.

Thanks for posting.

vmaxer

snow wrote: »

Hmmm..... considering that your 1.2TL's are an easy load to drive compared to the original SRS 8 ohms vs 4 ohms unless the caps in the amp are getting tired or some other problem with the amp is occuring your ears should give out before the amp does unless your living in a gymnasium. You should be well over 115 DB before the amp starts to clip which for most sane humans is more than loud enough.

If you were driving the original SRS I would suggest the Sunfire 300 X 2 it is capable of driving very low impedance loads far easier than any of the other Sunfire amps 405 x 5 or 7 or the 600 x 2.





REGARDS SNOW

I rebuilt the crossovers a few months back per the suggestions here on the forum. All Sonicaps and mills. I removed the polyswitches also.

I would guess that the open area is in the neighborhood of 7,000 cubic feet. They aren't in a room that can have the doors closed. My living room is open to most of the rest of the house, including the upstairs. They are also about 18" from the wall behind them due to them having to be 2" in front of anything beside them.


I don't have the pooping on all songs either. If I play Millage Gilbert, Let's Straighten It Out, the drum hits will pop them at high volumes.

Don't take this wrong, I love the speakers and the sound from them. The bass is a bit weak and I do get the "popping" when playing too loud.

I am very curious about the driver control statement.

heiney9

Anytime a driver "pops" or bottoms out it's from underpowering which can result in loss of driver control.

I also agree with SNOW, I had an Adcom 545 for a long time and even when I very occasionally ran it to it's limit (clipping lights faintly flashing) I never popped or bottomed a driver in my 1C's.

Good luck Turbo and let us know how the NAD works out. DO check the seals and make sure the SRS's are decoupled from the floor and rock solid with spikes, etc. And yes, your room could have a lot to do with the lack of proper bass response too. Probably a combo of all these things as well as amplification.

H9

heiney9

vmaxer wrote: »

I rebuilt the crossovers a few months back per the suggestions here on the forum. All Sonicaps and mills. I removed the polyswitches also.

I would guess that the open area is in the neighborhood of 7,000 cubic feet. They aren't in a room that can have the doors closed. My living room is open to most of the rest of the house, including the upstairs. They are also about 18" from the wall behind them due to them having to be 2" in front of anything beside them.


I don't have the pooping (I think you meant popping -lol) on all songs either. If I play Millage Gilbert, Let's Straighten It Out, the drum hits will pop them at high volumes.

Don't take this wrong, I love the speakers and the sound from them. The bass is a bit weak and I do get the "popping" when playing too loud.

I am very curious about the driver control statement.

Very large, open rooms with high vaulted ceilings are very, very hard to pressurize. This is the rare instance where I would recommend a sub to fill in the low end so you don;t have to push your amp so hard into clipping to get the sound level or impact you desire.

Or get soemthing like a Pass Labs X300 for amplification. You will not have the same problem with that amp. Of course maybe like me you don't have $6K to spend

H9

turbopantera

Thanks for all the suggestions, I will post a follow up when I get everything checked out. I am new to this forum and perhaps I should of done an introduction first. As an engineer, I tend to ramble on and sometimes assume that others "just understand". Bad habit. Any way, if anything is happening in the Illinois area, I would like to meet some other SDA fans, experience other systems and discover new music. I have always wondered what tubes sound like on the SDAs.

heiney9

Turbo, you're welcome to attend. We have several impromtu, casual meetings at various members homes. We call ourselves RAS (Rockford Audio Society). Most of us live in or near the Rockford area. There are about 6-8 hard core members and we mostly shoot the ****, talk about music, drink, eat and sometimes listen to gear - lol. We just had a GTG a couple weeks ago so it'll probably be after the Holidays.

Either ask again in the future or if I remember I'll send you a PM as we sort of keep in contact off the board.

McLoki (Michael) is in your area as well.

H9

snow

vmaxer wrote: »

I rebuilt the crossovers a few months back per the suggestions here on the forum. All Sonicaps and mills. I removed the polyswitches also.

I would guess that the open area is in the neighborhood of 7,000 cubic feet. They aren't in a room that can have the doors closed. My living room is open to most of the rest of the house, including the upstairs. They are also about 18" from the wall behind them due to them having to be 2" in front of anything beside them.


I don't have the pooping on all songs either. If I play Millage Gilbert, Let's Straighten It Out, the drum hits will pop them at high volumes.

Don't take this wrong, I love the speakers and the sound from them. The bass is a bit weak and I do get the "popping" when playing too loud.

I am very curious about the driver control statement.

Part of the problem with weak bass in your case is the speakers are too far from the rear wall try putting them back to within 10" -12' as far as the driver control issue goes your amp needs to be able to handle the transients that occur during heavy bass, if you have it turned way up in a large room and it is using let's say 300 wpc average it may well hit 1200 -1400 wpc or more during these heavy bass passages I think this is whats happening in your case and with turbo also. You are requiring the amp to be almost maxed out to obtain the volume wanted then playing a heavy bass laden album is causing it to distort hence the popping.

Here are a couple reviews/reports on the Sunfire 300 X 2 and you can see it is very capable of playing very low impedance loads.

http://www.sdinfo.com/volume_2_1/productr.html



REGARDS SNOW

heiney9

Here's the link to the original 1985 Stereo Review magazine review. They had glowing things to say and the bass response and bass distortion were impressive.

http://www.polksda.com/srsreview.shtml

Pay close attention to the tha lab tests side bar, esepcially the top of the 2nd column.

Also the very last paragraph of the article.....talking about what you need to really drive the SRS's

heiney9

The other thing people don't realize is because the speakers are "coupled" togehter with the chord for the dimensional drivers this puts extra stress on the negative rails of any amplifier so add to that low impedance which varies widely based on content and volume and you see why most amps regardless of rating have issues.

H9

snow

Just to clear things up a little for those who may find it hard to understand why I said with low impedance loads you are better off with the Sunfire 300 X 2 versus the 600 X 2 or 400 X 7 etc is that even though you initally have more wpc with these other amps you actually have more headroom at lower ohm loads with the 300 X 2 then the others, they are basically the same amps except you give up a little capability to play lower ohm loads with ease for higher wpc ratings on the others and with 768 wpc into 4 ohms and 1460 wpc into 2 ohms according to the test results on the second review I dont think your losing out much.



REGARDS SNOW

inspiredsports

I would be interesting to get Matt's weigh-in on the 1C tweeter mod. I personally would opt to put it back the way it was designed. Good luck. Gotta run.