AMP or upgrade my SUB?

fgr41

I currently have a Sony STR-DE985 powering a Sony SA-WM40 sub, 2 RT800i Polk fronts, 2 RT600i rears, and a CS400i center. I am running the speakers directly off the receiver and have bi-wired the fronts and center. I am very happy with the set up but...

I was watching U-517 last night, durring the depth charge scene I was extreemly disapointed. I had heard that is the movie to really test out your sub, well mine fell WAY short. In fact I didn't find the scene exciting at all, it seemed like my sub was sleeping.

I was demo'ing the system for a buddy the other day and put on Eric Clapton unplugged. Everything was good till I wanted to really crank it up. I got around 50 something on a 75 volume scale and it happened. I first thought the speakers were being pushed too hard then I looked at the receiver. All the lights on the receiver were dimming with the music. It simply could not put out enough power.

My question is this...

Should I get an amp to help give the speakers the power they need? I dont usually push my equipment too loud but having that option is nice and I wonder if an amp would clean up the sound some.

Should I dump the receiver and go for another? If I changed to a new receiver would I have the same issues?

Would sticking with the receiver and just updating the sub be better since I don't usually have the volume up that high.

The $ is a BIG issue as I am back in school (thanks to getting laid off), and I have a baby on the way. I am thinking my budget will be around 2-400, the lower the better.

Fastmerc

Im not super familiar with Sony subs...but if the one you have is not powered I would suggest getting a seperate amp to power it or go ahead and get a internally power sub. Im sure your budget would allow for a fairly decent powered sub especially if you look for a clean used unit. If you did that you would certainly take some heat off your reciever plus the sub can go with you to your next system as you may want to upgrade in the future.

I would say for the money you would be hard pressed to find a great reciever as oppossed to the sub. As far as purchasing a seperate amp you may want to take your sub(if possible) and audition some amps to see how the sub performs, you may find you dont like it even with the boost in power.

Just my thoughts, Im sure others could chime in and direct you to a good sub in that price range as the topic comes up often here.

Good luck,
Brett

fgr41

The SA-WM40 is powered 12" subwoofer with 120 watt amplifier. The receiver should not be pushing much to it as im running it on the Pre-out of the receiver.

Fastmerc

Well that may change the solution then...lol...however if the bass is what you think is lacking 120w sub may not be enough power for your room size.

You might want to try playing around with the placement of the sub. If you take the sub out of the picture are the mains and surrounds doin for ya?

You may also want to check the AC line you are using. Try finding out how many items are on the circuit. If you own your residence you might want to think about a dedicated line and a power conditioner.

Dr. Spec

What are your speaker size settings for your digital bass management in the Sony receiver?

They should all be set to small and the sub should be set to yes. Use a crossover of 80 Hz if it is adjustable in the Sony.

Make sure all your bass and treble controls are set to flat, especially the bass controls.

All your speaker levels should be adjusted to 75 dB at the seat with the internal test tones of the receiver.

The sub level control should be set to around -3 or -5 in the Sony receiver, and the sub level should be adjusted with the sub amp volume knob to 78 dB at the seat on the sub test tone.

If you don't have an SPL meter, then get one at Radio Shack for about $35 (on sale for $25 right now on line but might be out of stock due to a run on them). Use C-Weighted Slow for all your monitoring and calibration.

Finally, the WM40 rolls off sharply around 35 Hz and will never do the U-571 depth charges complete justice. Only the best subs can.

You will get FAR more bang for the buck replacing your sub than your receiver, especially if you run all your speaks on small. Your budget is too low for a decent sub, though. Save your money and wait until you have about $600.

Doc

Dr. Spec

Originally posted by fgr41
I was watching U-517 last night, during the depth charge scene I was extremely disappointed. I had heard that is the movie to really test out your sub, well mine fell WAY short. In fact I didn't find the scene exciting at all, it seemed like my sub was sleeping.

Try 115-116 dB (C-Weighted) peaks on that scene. That's about 120 dB unweighted (true).

Enough to turn your guts to Jell-O. That's a great scene on the right sub. Most of the depth charges are in the 25-30 Hz region, but there is a bunch of infrasonic information extending down to about 10 Hz.

Doc

Dr. Spec

Also, if you are using the line level inputs, make sure you are using the unfiltered input for LFE.

If the WM40 doesn't have one, set the sub filter all the way to its highest setting to avoid double filtering with the Sony receiver.

Doc

fgr41

Originally posted by Dr. Spec
What are your speaker size settings for your digital bass management in the Sony receiver?

They should all be set to small and the sub should be set to yes. Use a crossover of 80 Hz if it is adjustable in the Sony.
Done
Make sure all your bass and treble controls are set to flat, especially the bass controls.
FLAT? That does not bring out the color in the speakers that I think does them justice. The receiver has a built in EQ and I have tweaked the settings for the speakers a bit. Can you tell me why they should be set to FLAT?

Finally, the WM40 rolls off sharply around 35 Hz and will never do the U-571 depth charges complete justice. Only the best subs can.

You will get FAR more bang for the buck replacing your sub than your receiver, especially if you run all your speaks on small. Your budget is too low for a decent sub, though. Save your money and wait until you have about $600.

$600 is going to be a long wait. $3-400 is going to take a while, I was hoping to find something at CC that would perform better than the WM40 and upgrade it w/in a year with the CC upgrade plan.

Thanks for the info

Dr. Spec

The only reason I suggested flat for the tone controls was that upping the bass draws a great deal of power from the amplifier. And you said the receiver was running out of steam.

I suppose if you are now low passing everything to the sub at 80 Hz, it shouldn't matter much since you will be using the sub's amp to handle any boost in the bass curve.

Does it sound any better or does the receiver have any more perceived volume or power with all the speaks set to small?

Doc

polkatese

Doc,
If in most cases, 80 hz is the proper crossover setting (and it's also THX spec.), I am curious what advantage would be achieved in setting the X/O at say 60 hz or even 40 hz? I am curious, assuming that the front speakers are set large (full-range capable, well, almost), everything else are small? thanks..

faster100

Originally posted by fgr41

Originally posted by Dr. Spec


$600 is going to be a long wait. $3-400 is going to take a while, I was hoping to find something at CC that would perform better than the WM40 and upgrade it w/in a year with the CC upgrade plan.

Thanks for the info

Buy my few month old polk psw404 for $295.00 + shipping in box with papers,

fgr41

It does throw more bass if the speakers are set to small and the crossover is at 80. The sound is by far better.

I tried moving the EQ on the speakers to flat and it was just that, flat. I loose too much quality and reset the speakers with the EQ on, much better.

FASTER100, not a bad price but it's going to be about 4-6 months before I will have $ for a new sub. Till then I think I am going to have to tweak my sub position and play with the EQ and X-over.

mantis

I say go for the psw450 polk sub.It's nice powerful and quick.Great affordable sub.
Then upgrade the receiver to someting else like a Denon avr3803.

Polkatese,
setting the crossover lower,not running large my friend allows the speakers in small to have alittle more bottom end.Most polk speakers go down in the 50 hz range,there you can use this.It's not nessary as a good quality sub will perform well here.But it's fun to play around with.
In your setup I suggest setting your LFE or crossover internal in the B&K to 60hz.Allow the Lsi series to play what they can play.ALl LSi speakers can play 60hz and above.The center will sound a bit more fuller......go for it.All speakers set to small excapt the Lsi15's run them in large.They have usuable bass down to 32hz.After that they start to fall off quickly.

Dr. Spec

If your AVR routes the LFE channel through the BM circuit (and most do) setting the crossover to the sub lower than 80 Hz can lop off the top of the LFE channel and you can actually lose bass.

That would be one reason against experimenting with 60 or 40, etc.

The high pass filter rate is usually 12 dB/octave, and the speaks will therefore play far lower than the selected crossover point.

Doc

mantis

I never had any problems with bass management is well in the higher quality AVR's.

Most that are adjustable are higher quality and I never experienced bass loss.Good point you bring up and I'll let you know if I ever run into problems with setting the crossover lower then 80hz.Alot of your budget avr's lock out at 100 or 90 hz.Yamaha was this way for years and years.

polkatese

Thanks Dan and Ed for your insights on xover! I had just changed my xover to 80 hz today, from 60 hz, and I noticed immediately that the low details is more profound. Quite a revelation to the new found details. I had always set them up at 60 hz since I got it, so I will continue play with them some more. Thanks again..

fgr41

Thanks to everyone for thier responces. I think there is some good info for all in what has been said here.

I tweaked thing a little more tonight and things are getting better little by little. I am sure that a sub is in my future, just a matter of what and when.

Once that is done on to the receiver, then... ( it will never end )

mantis

polkatese,
thats because you own a REL.......LOL.whatever you send to it it's going to enhance your experience,now if only they would make full range speakers........hmmmmm

Playing with crossover setting is fun and a good learning experience.

Dr. Spec

http://www.hometheaterhifi.com/volume_9_3/feature-article-multiple-crossovers-9-2002.html

This IMO is the seminal article on subwoofer crossover frequency. I suggest reading and bookmarking for future reference.

The problem with the LFE channel is that it can only go the mains or the sub. The LFE channel usually has strong content up to about 80 Hz, even though theoretically by design is can go up to 120 Hz with a brick wall filter. So setting the crossover to 50 or 40 will often lop off the top of the LFE channel when playing DD and DTS DVDs.

The THX crossover of 80 Hz wasn't pulled out of thin air - is the best frequency for capturing all of the LFE channel and also allowing larger surround channel speakers to produce strong bass down to about 50 Hz.

If your AVR or pre/pro can adjust the crossover of the LFE channel independently from the surround bass, then you could indeed keep the LFE channel at 80 and drop the others to 60. But that would be sort of defeating the purpose, I suppose.

Some people think that using 80 is too high because they can localize the subwoofer. But keeping the sub near the mains and center and allowing the gentle slope of the high pass filter rate help mask the location of the sub certainly helps.

Also, the best subs have such low THD that they will not produce audible harmonics at the higher frequencies (above 100 Hz) that can be more easily localized.

If you can close your eyes and easily point your finger at your sub with an 80 Hz crossover, it is probably producing audible harmonic distortion above 100 Hz.

Regardless, for 2 channel music only (no LFE channel), you could certainly try a 60 Hz or 40 Hz setting without losing the LFE channel. But as you have discovered, the best subs can do 40-80 Hz better than most "full range" mains.

My RT800i's on full range cannot even do low E (around 40 Hz) justice on a bass guitar. They start to roll-off around 45 Hz and are probably 5 dB down at 40 Hz.

Doc

polkatese

Dan, it's definitely fun tweaking exercise, I am going to leave it at 80 for a while and see what it brings..

Ed, thanks for the article link, I will keep it for reference.

TonyPTX

Originally posted by fgr41
$600 is going to be a long wait. $3-400 is going to take a while, I was hoping to find something at CC that would perform better than the WM40 and upgrade it w/in a year with the CC upgrade plan.

Thanks for the info

If you're stuck in the CC upgrade hole, you might also want to consider the Velodyne subs available at CC. If I remember right, they carry the 12CHT series.

Anthony

fgr41

I am most impressed with this forum and the great responce I got from this post. I was thinking initially that all I would hear is "get rid of that sony receiver and get something with some real power". Instead I got a more honest and detailed answer on how to make the best using the guidelines that I initially listed.

Thanks to all for the info on X-over and sub settings which helped me understand what it all means. This place is such a good source for info, I only wish I would have found it sooner.

You all ROCK!