340s with/without subwoofer

[mv1612]

Hi,

I have a question regarding the 340s. Let’s say you have three setups. First, you have them connected as “Large” to a receiver, with a subwoofer. Second, same as above but the monitors set as “Small” with a crossover suitably chosen. Third, have them connected to a stereo amplifier with no subwoofer.

I know that the first setup is obviously wrong. To quote David, “running the 340s full range will distress the entire bandwidth of the woofer section, up until about 3Khz”, and “for optimum (always recommended) performance, the speakers MUST be run with a minimum of a 65hz high pass filter (“small”)”. But then what about listening them without a subwoofer, the third option? Should I understand that their performance without a sub is to a certain point degraded because they’re trying to reproduce the full range? To what extent?

Virgil

[Lou-the-dog]

I run my 340's both ways... with a sub and without. Sometimes I have them hooked up to a Denon 3803 and run the sub with this configuration. Sometimes I have them hooked up to an integrated tube amp which I run sans sub. My tin ear can't pick up any degradation. I suspect a sophisticated measuring rig would be needed to reveal the difference. I do prefer the extra bass the sub provides however so I'll be looking for a way to integrate the sub with the tube amp.

Randy

[Quinn]

I have 340s in a two channel music only rig without a sub and they sound great. There is a post somewhere from davef that he runs his 340s w/o a sub at times.

EDIT- I found the link. This post. http://forum.ascendacoustics.com/sho...1&postcount=13

In this thread- http://forum.ascendacoustics.com/sho...8&page=1&pp=10

[davef]

Hi mv1612,

Welcome to our forum!

Running the 340 mains full range is not necessarily wrong. It all depends on how large your room is and how much output you demand. The more bass below 50Hz that the speaker is being asked to reproduce (dependant upon output level), the greater the chance of hurting the performance of the delicate midrange frequencies. In a large room and at loud volumes, full range is not recommended if you want the best performance of the mids... However, in a smaller room or at moderate volumes, full range will not be a problem.

What are your room dimensions?

[mv1612]

Thanks to Dave and all of you for the replies. I'm relieved, it seems that the efect, if any, is kind of "subtle", not at all obvious. My room dimensions are 16/14/9, so not a big room.

[mv1612]

And Quinn, thanks for the link!

[NewBuyer]

...The more bass below 50Hz that the speaker is being asked to reproduce (dependant upon output level), the greater the chance of hurting the performance of the delicate midrange frequencies...

So when you said earlier that "running the 340s full range will distress the entire bandwidth of the woofer section, up until about 3Khz", you meant only at louder volumes, yes?

[mv1612]

I think I should say where I took those quotings from. They're part of Dave's observations toward an unfortunate reviewer from hometheaterforum, who took a blind test between the 340s with subwoofer and the Rocket 550 but chose to let the 340s as "Large". From what I understand, in this situation you not only stress them to reproduce the whole spectrum, but you end up with a bunch of interferences with the sub, having two sources reproducing the same frequencies. Maybe Dave wants to share something about this moment, maybe not... these are not very pleasant memories, thinking at the controversy that followed.

So anyway, I'm sure that when there's no sub, there isn't anything bad to be noticed.

Virgil.

[davef]

Hi Virgil,

The review you were referring to wasn't so much as a review, but more so an A/B comparison between a bookshelf speaker used with a subwoofer (CMT-340 + STF1) and a well regarded full range floor standing speaker.

Many, many things were questionable about that comparison, including the fact that the 340 mains were set to large thereby receiving a full bandwidth signal, even though they were being used with a subwoofer...

For ANY woofer being used in a ported enclosure, the woofer will exhibit extreme excursion below the tuning point of the enclosure. The lower the frequency and the higher the output, the more excursion. This excess non-controlled movement will have an adverse effect on the delicate midrange frequencies that it is trying to reproduce at the same time. This is one of the reasons that quality speakers have specialized drivers for specific frequency ranges.

The CMT-340s having a tuning point of 55Hz. In the comparison you referred to, they were played at very high levels, with full range signals, in what I believe was at least an 8000 cubic foot room. I was quite impressed that the speaker even handled the deep bass output demands in a room this large. If the speaker was set to small (as it should have been for this type of usage) thereby rolling off the low frequencies and allowing the sub to properly integrate with the speaker, maximum output levels would have increased, distortion would have dramatically decreased and the detail and clarity of the midrange would have been much improved. Would the difference have been audible? Very much so…

Also of important note, a woofer that is capable of deep bass must have increased mass, be extremely stiff and will usually exhibit poor damping. This is almost the exact opposite of a woofer that is designed for accurate mids and fast transients. This type of woofer must have very low mass and superb damping. Generally speaking, the lower the mass of the cone, the more accurate the transient response is (faster) and the better ability for the cone to resolve detail. Here is a good way to imagine this.. Picture a rock dropped in a pool of water.. how quickly do the waves travel and then disappear? How many waves are produced? Now drop the rock in a liquid of much heavier density, (something like honey or molasses comes to my mind)….. Visualizing the difference between the two is easy… and this visualization can be thought of as “detail”.. Now, take a bucket full of each and splash it at someone.. which one is going to have more impact? This visualization could be thought of as bass capability…

The woofers used in our CBM-170 and CMT-340 are very low mass, with excellent damping. They are specifically designed for fast transients, low distortion and impressive levels of details. They are simply not designed for deep bass.

In your room size (about 2000 cubic feet), you can certainly run the 340 mains full range and they will deliver tight bass into the 50Hz region. However, if your intentions are to avoid a subwoofer, have exquisite mids, deep bass, and be able to maintain this performance at very loud levels, I would recommend a much larger loudspeaker (more cabinet volume) with a woofer dedicated to bass, a dedicated midrange driver and of course an excellent tweeter...

Or... you could simply and affordably, high pass the 340 mains and add a subwoofer

hope this helps!

[mv1612]

Great post Dave! Thanks, this certainly clearifies things. I'll almost surely buy a pair of 340s, just that I still have to wait. I'm a "fresh" canadian, coming from Romania, and I can't afford them, not yet. If all goes well, I'll be able, maybe in a year, to order a B-stock pair... hopefully.

Cheers, Virgil.