sda 2b question

superjunior

not too long ago I picked up a pair of 2b's from lightman. they sound excellent but at modestly loud levels the tweeters cut out. after turning the volume all the way down for a few seconds they kick in again. I figured this was probably some sort of protection circutry and contacted Russ. He confirmed it is the polyswitch that causes this? This is quite frustrating as they cut off at fairly modest levels, no where NEAR distortion or clipping. Can the polyswitch be bypassed? if so, am I risking damage elsewhere? I must admit, the kid in me likes music LOUD. am I wasting my time with these little sda's? thanks ahead
Dan

Face

Call Polk, they can send you replacements or you can bypass them if you're using a good amp.

Conradicles

Super, those are actually my old 2B's and they never once did that to me. I do not listen too loud, but I did at times really, really crank them. Like I said, never once did the poly-switch kick out.

What amp are your pushing them with? Are you absolutely sure they are not wired out of phase?

superjunior

Conradicles wrote: »

Super, those are actually my old 2B's and they never once did that to me. I do not listen too loud, but I did at times really, really crank them. Like I said, never once did the poly-switch kick out.

What amp are your pushing them with? Are you absolutely sure they are not wired out of phase?

I'm using my emo xpa-3. in 2 channal its pushing 250w to each speeker. I am using the interconnect cable, not sure what wired out of phase means? I can push my a9's to ear-bleading levels with no issues. am I just expecting too much out of these little guys? they cut out before I would even consider it being too loud

fbm211

Out of phase means you have the pos/neg connections mixed up.

NJPOLKER

Maybe Russ rubbed his little thing on them and degraded the polyswitches.

concealer404

God i hate polyswitches....

superjunior

fbm211 wrote: »

Out of phase means you have the pos/neg connections mixed up.

alright than, this is definatly not the case.

superjunior

NJPOLKER wrote: »

Maybe Russ rubbed his little thing on them and degraded the polyswitches.

lol..:D

F1nut

It's entirely possible that the poly's have degraded from age and/or from being tripped too many times. It's also possible that your amp is clipping, even though you don't think it is and that the poly's are doing their job.

Consider that for every 3dB increase in volume it takes double the power and your 2B's have rated efficiency of 90dB at one watt...

90db - 1 watt
93dB - 2 watts
96dB - 4 watts
99dB - 8 watts
102dB - 16 watts
105dB - 32 watts
108dB - 64 watts
111dB - 132 watts
114dB - 264 watts
117dB - 528 watts
120dB - 1056 watts

Do you have an SPL meter? If so, you can determine at what dB level the poly's are kicking in, which will tell you if it's bad poly's or if your amp has gassed out.

superjunior

F1nut wrote: »

It's entirely possible that the poly's have degraded from age and/or from being tripped too many times. It's also possible that your amp is clipping, even though you don't think it is and that the poly's are doing their job.

Consider that for every 3dB increase in volume it takes double the power and your 2B's have rated efficiency of 90dB at one watt...

90db - 1 watt
93dB - 2 watts
96dB - 4 watts
99dB - 8 watts
102dB - 16 watts
105dB - 32 watts
108dB - 64 watts
111dB - 132 watts
114dB - 264 watts
117dB - 528 watts
120dB - 1056 watts

Do you have an SPL meter? If so, you can determine at what dB level the poly's are kicking in, which will tell you if it's bad poly's or if your amp has gassed out.

thanks Jesse, I'll have to pick up an spl meter.

superjunior

thanks for the comments and suggestions, I guess I have just one question left and any opinions are welcome. I like music loud to mind blowing LOUD AS HELL. Am I wasting my time with the 2b's?

Disc Jockey

superjunior wrote: »

thanks for the comments and suggestions, I guess I have just one question left and any opinions are welcome. I like music loud to mind blowing LOUD AS HELL. Am I wasting my time with the 2b's?

Ha, not in my opinion. Mine get as loud as I could ever want them and still sound clean. I like them very loud at times also, and this is in a fairly large room.

F1nut

superjunior wrote: »

thanks for the comments and suggestions, I guess I have just one question left and any opinions are welcome. I like music loud to mind blowing LOUD AS HELL. Am I wasting my time with the 2b's?

I like it loud at times.....117dB is as loud as I've measured here and it's about the limit of my rig. It's very loud and will cause permanent hearing damage in short order. Therefore, I rarely listen at that level and when I do it's not for very long because I still want to be able to enjoy the music years from now. One also realizes at some point that it's not how loud the music is, it's about how good it sounds, although I have to say my rig still sounds stellar at 117dB.

Anyway, what I'm trying to say is learn to appreicate the quality of the sound rather than the volume level.

If you want rock concert levels of 120+dB, get a 2000wpc pro amp and 105dB efficient speakers. You'll be deaf in no time.

JohnLocke88

NVM... dumb question

superjunior

F1nut wrote: »

I like it loud at times.....117dB is as loud as I've measured here and it's about the limit of my rig. It's very loud and will cause permanent hearing damage in short order. Therefore, I rarely listen at that level and when I do it's not for very long because I still want to be able to enjoy the music years from now. One also realizes at some point that it's not how loud the music is, it's about how good it sounds, although I have to say my rig still sounds stellar at 117dB.

Anyway, what I'm trying to say is learn to appreicate the quality of the sound rather than the volume level.

If you want rock concert levels of 120+dB, get a 2000wpc pro amp and 105dB efficient speakers. You'll be deaf in no time.

thanks again f-1. I hear what your saying. I'm not trying to blow my eardrums, I just like quality sounding music at concert levels. maybe I should start with a much bigger amp...

GTB

superjunior wrote: »

thanks for the comments and suggestions, I guess I have just one question left and any opinions are welcome. I like music loud to mind blowing LOUD AS HELL. Am I wasting my time with the 2b's?

I've had my 2B's since 91....they will rock you! Something's not right.

You are definately NOT wasting your time.

Greg

hoosier21

superjunior wrote: »

thanks for the comments and suggestions, I guess I have just one question left and any opinions are welcome. I like music loud to mind blowing LOUD AS HELL. Am I wasting my time with the 2b's?

I would say yes. Great speakers, but not a mind blowing loud system.

pitdogg2

you know I'm having the same problem with my SDA2B's I run mine with a Carver TFM45 C16pre and Sony ES x33 cd player with 10ga. speaker cable to bananas on each end. My SDA's will both trip the tweeters when my TFM meters bounce between 50 and 90 watts on the TFM45 meters. They sound great but it just drives me nuts because it just seems i can't get the sound i want from them. My Carver amp and pre amp was repaired and serviced 4 yrs ago by Roland at Carver Service I can't see why there would be anything wrong with either. My other speakers Cerwin Vega D7's will pop the fuse when the meters start bouncing past the 180 mark but that to be expected because they are rated at 200wpc.
I want to rebuild the SDA's but my X-overs do not look like the others I've seen on the forum here.

pitdogg2

pitdogg2 wrote: »

you know I'm having the same problem with my SDA2B's I run mine with a Carver TFM45 C16pre and Sony ES x33 cd player with 10ga. speaker cable to bananas on each end. My SDA's will both trip the tweeters when my TFM meters bounce between 50 and 90 watts on the TFM45 meters. They sound great but it just drives me nuts because it just seems i can't get the sound i want from them. My Carver amp and pre amp was repaired and serviced 4 yrs ago by Roland at Carver Service I can't see why there would be anything wrong with either. My other speakers Cerwin Vega D7's will pop the fuse when the meters start bouncing past the 180 mark but that to be expected because they are rated at 200wpc.
I want to rebuild the SDA's but my X-overs do not look like the others I've seen on the forum here.

guess this may help My Xovers are dated july 1987 and there are two parts to it I will post pictures or send them to someone if they would like to see

F1nut

You need to replace the poly switches in your Polk's. Call Polk CS and they will send you new ones for free.

My other speakers Cerwin Vega D7's will pop the fuse when the meters start bouncing past the 180 mark but that to be expected because they are rated at 200wpc.

That's not how it works. What's happening there is that your amp has run out of steam and is clipping.

pitdogg2

F1nut wrote: »

You need to replace the poly switches in your Polk's. Call Polk CS and they will send you new ones for free.



That's not how it works. What's happening there is that your amp has run out of steam and is clipping.

just a little confused? The Carver TFM45 is rated at 375 WPC how at 180 wpc is it running out of steam and clipping? When I had it serviced Roland told me my TFM45 was built just a little different than most as it rated at 425WPC. At the time he told me that this was not that unusual because some of the M series that were rated at 375wpc drove in excess of 475 wpc. Rita who works for Bob Carver and i talked and she also confirmed this, that some of the M and TFM series were over built and pushed more than what was the norm. Rita also just had some of those on Ebay recently and she stated that in her auction. I would really understand the clipping if i was bouncing the needles close and past the 375 mark on the meters. I had a pair carver 9 mono blocks(which got stolen) and the same Cerwin Vega D7's and they would still pop the Xover fuse at 200 on the meter yes i could get them to play longer with a higher than factory fuse but then i would just melt them down.

F1nut

There's a big difference between a bench test rating and real world use. Transients are but one example.

Another thing, those meters aren't exactly telling you the truth.

inspiredsports

superjunior wrote: »

thanks for the comments and suggestions, I guess I have just one question left and any opinions are welcome. I like music loud to mind blowing LOUD AS HELL. Am I wasting my time with the 2b's?

I guess I'm late to the party, but wanted to share that my 2B's will sustain a clean 115 db at the center point of my 24 X 26 X 8 listening area.

I rarely drive them beyond 95db as that is plenty loud, but it's nice to have the headroom. Make sure you periodically check the tightness of the driver screws if you consistently listen at these levels.