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View Full Version : should I set my 340s "large" or "small?"



Eddie
04-02-2005, 08:45 PM
Which setting do you all use?

The 340s are supposed to go down only to 55Hz, so what happens if the receiver sends it frequencies under its 55Hz floor? Is there something in the speaker which will automatically block out those under-55Hz frequencies, or will they just cause distortion?

Right now I have my front 340s (L/C/R) set on "small" with the receiver's crossover at 80Hz (its lowest setting), and the subwoofer set in "LFE" mode which if I understand correctly means that its internal crossover is not used, it simply reproduces whatever the receiver feeds it.

According to this article, if you have anything other than tiny satellites, having your speakers on "large" will make the subwoofer blend in more:

http://www.polkaudio.com/home/faqad/advice.php?article=bassmanage

What's everyone's experience been with these kinds of settings?

jimsiff
04-02-2005, 11:31 PM
I have my 340s set to small, crossed over at 80 hz. My sub blends with the 340s just fine. From what I understand, all Ascend speakers are designed to be used as small when a subwoofer is in use. That said, the 340s have enough output below 55 hz that they can do a fine job running full range without a sub.

The 340s won't block those frequencies lower that 55 hz. They just won't be reproduced at the same level as 55hz-20khz. The frequency response of the 340s rolls off below 55 hz, so lower frequencies won't be reproduced as loudly.

If you set your speakers to large, your receiver's amplifier has to work harder. Bass frequencies take more power to reproduce cleanly, so you lose amplifier headroom. You won't be able to play your system as loud before distortion and clipping become a factor.

gman8691
04-03-2005, 06:19 AM
I have the 56txi. The auto eq always sets all my speakers to large so I have been switching them back to small x'ed over at 80. Last nite I tried the fronts (340's) set to large and the rears (170's) set to small with the sub set to plus and was not happy with the sound I got while watching "54". This movie has a disco soundtrack and it seemed to be missing so much bass I had to crank up the sub all the way. For my money I think small all the way around sounds and blends the best.

bikeman
04-03-2005, 06:55 AM
According to Dave F., when using a sub, set the 340's to small and crossover between 65 and 80hz. I've experimented extensively with small, large and normal (whatever that is) and small is the way to go. No question.

David

Lou-the-dog
04-03-2005, 10:45 AM
Here is a quote from DaveF addressing this. The quote came from another forum as Dave addressed the outcome of a poorly set up user review of the 340's where the 340's were set to large AND used with a subwoofer.


"...but running the 340s full range will distress the entire bandwidth of the woofer section, up until about 3Khz. At which point the woofers are about 18dB down in response. For optimum (always recommended) performance, the speakers MUST be run with a minimum of a 65hz high pass filter (“small”). As Curtis mentioned previously, it will make an audible difference and the larger the room and more demanding the source material, an even larger audible difference…

Our CMT-340 are tuned to 55hz, and frequencies below 55hz will cause excessive woofer movement, increasing dramatically as frequency decreases (this is the nature of a ported enclosure). These woofers were specifically designed and optimized for a detailed midrange response and extremely fast transients, not deep bass. In fact, the mass of the cone (or for those with a bit more technical knowledge, MMS) is just under 10 grams. I strongly doubt you will find a 6.5” woofer with an MMS less than this anywhere, one of the reasons we chose “Aerogel” as the material. This woofer, while it might handle the excessive movement caused by extreme low frequencies, is simply not designed for this type of use. If the woofer is being asked to reproduce (for example) an 800 Hz signal (vocal band) while it is also attempting to reproduce a signal below 55 Hz (drums, bass guitar, organs etc.), the reproduction of the vocal band will be GREATLY compromised, as the woofer cone and suspension system are trying to deal with the low frequencies. The cone itself will not only be warping and bending, but it might be forced outward 3-4mm, forcing the large majority of the voice coil windings to be, as we like to term, “out of the gap”. The gap is the small space created by the center pole piece and surrounding magnet, which creates the EMF (electro magnetic fields) which drive the woofer. In simpler terms, the less windings that are located in the gap and subject to the intense magnetic field, the greater the decrease in performance. At a 35hz signal at 90dB @1 meter in a small room, the coil will be completely out of the gap, any additional frequencies the woofer must reproduce at this exact point in time will not even be reproduced! Ultimately, the ideal woofer has all of its windings within the gap at all times (underhung design) but these woofers have their disadvantages as well (very limited excursion). As also stated above, the more a woofer cone bends and warps, the lesser the performance on the subtler areas of the response such as midrange reproduction. Everything suffers by running the 340s full range, especially in such a large room; soundstaging, vocal reproduction, power handling… the list goes on…

Another real problem with driving the 340s full range (or any loudspeaker for that matter) while using a subwoofer is integration. The subwoofer and loudspeaker will be reproducing the same frequencies, which is far from ideal. Because these duplicated sound waves are being reproduced in different locations of the room, some of the frequencies will be in phase, some out of phase, thus causing comb filtering. Some frequencies will be bumped up; others will have a hole…"



Makes sense and I hope this helps.

Randy

Lee Bailey
04-03-2005, 02:20 PM
I use 80Hz crossed over in the receiver on my 340's. The Polk guide to me makes an error when saying you can hook the sub up in parallel with your mains, this is especially true if were using smaller speakers that were not meant to be driven the full frequency range. It may also cause a problem with the resulting impedance presented to the amplifier, since running speakers in parallel lowers the impedance.

If I wanted to use the speaker level jacks on my sub, I would first find out what the crossover is set to, as the speaker level jacks normally have their own crossover, and do not use the crossover control on the back of the sub. I found this to be true on my SVS sub, after asking SVS about it.

There was an interesting thread over on AVS about how Definitive Technology recommends using BOTH the sub input jack AND the speaker level inputs at the same time. In that situation, the idea is to only route LFE through the sub-out jack on the receiver, then set the fronts to large, and feed the amp into the sub's speaker level inputs, and feed your front speakers through the sub's speaker level output jacks.

Eddie Horton
04-03-2005, 02:49 PM
Lee, in regards to the Def Tech setup method.....if you use the LFE in on the sub, and also hook your mains up to the sub using the speaker level inputs and outputs, wouldn't you just be trading the receiver's crossover for the sub's? To the original poster: Set them as small with a crossover somewhere between 60 and 80Hz. They are not meant to be run full range.

Lee Bailey
04-03-2005, 07:19 PM
The idea was that it would sound better with all material, and the LFE is added only when watching DVDs that use the LFE track, so only the sub would be sent the signal at that time. Some people don't think that their receiver's crossover settings will deliver the best sound.

The receiver's crossover in the Def Tech setup would only redirect the remaining SMALL speakers to the front speakers, which now includes the subwoofer, so you would want to be careful what crossover point you want. The receiver's internal crossover should do nothing to the LFE signal. It should all be sent to the sub, with its highest frequency around 120Hz. I'd have to look up the Dolby spec to be sure of that though.

You would need to know just how your receiver handles bass management before trying this setup. They are NOT all the same.

Eddie
04-07-2005, 08:09 PM
Thanks for the feedback you guys, I'm relieved since I've always had my 340s set on "small."

The suggestion to use pre-outs with receiver set to "no subwoofer" and fronts to "large" came from a poster at the ecoustics.com forum who swears that he gets much "cleaner bass." I think he has Paradigm Monitor 5s, a speaker that I had found to be somewhat similar to the 340s so it was an intriguing thought!

Now how about bi-amping? I've been licking my chops at these used NAD 2200 amps they have going for around $200 on eBay recently... :D