Technical question, regarding running Sierra Towers at full range

[HEPD85]

Hi guys, I'm pretty new to the forums and will be a new owner of a set of Towers as soon as they are in stock again. I'm not new to the hobby per se, I'm no expert either, cut my teeth into audio after my first deployment in the Marines (used a big chunk of my deployment bonus on it :)) been at it ever since, look forward to my stay here.

My question pertains to what actually happens in a given speaker (in this case, the Towers) when they are fed a full signal (20 - 20k). As I understand it, most speakers actually don't reach down to 20 hz, so what happens if someone were to run them full range without the support of a sub for whatever reason, by this I mean would the speakers try to play it anyways at the expense of their own longevity or will the hardware simply ignore signals outside of their own capabilities?

I know some of you will ask for this so here goes: my set up includes an Emotiva UMC-200 as a pre-amp, and Emotiva XPA-3 running the speakers with 200 wpc at 8 ohm, and 300 wpc at 4ohms.

Thanks everyone

[curtis]

The hardware will try to play everything that is thrown at it.

You would have to be playing at pretty loud levels, or raise the EQ in the lower frequencies (below the speaker's specifications) to worry about abuse.

[HEPD85]

So if I don't mess with the EQ, I wouldn't have anything to worry about stay within a normal volume (below reference) correct? Are there any serious downsides of driving something like the Sierra Towers full range even for movie/music/gaming purposes?

In addition, will this affect the other frequencies also performed by the hardware?

[FirstReflect]

Sometimes, I think it's more helpful to look at things in a slightly different way:

The Sierra Towers can play very accurately, linearly, and powerfully down to 40Hz or so. Below that, they naturally are rolling off. And being a ported design, it's a fairly steep roll-off below that port tuning.

So, to me, the better way to look at it is that below 40Hz, the Towers are not going to be playing as loud as the signal is asking them to play if it's a true, full range signal.

To my mind, that means, "why worry about it?" Why attempt to eek out any significant output below the tuning frequency of the speaker? Why run the risk of setting them to "Large" or "Full Range" and then using an AutoEQ program (like Audyssey or MCACC or YPAO, or what-have-you), which might attempt to boost that lowest octave from 20Hz-40Hz?

To my thinking, it makes MUCH more sense to simply always set the Towers to "small", even if you do not have a subwoofer physically connected. If you are running them with no subwoofer physically attached, I'd set them to "small" with a 40Hz crossover, and never ever have to worry for a moment about bottoming out the woofers, or driving them into distortion by attempting to force out that lowest, single octave of bass.

I can tell you, I've been THRILLED with the quality of the bass produced by my set of 3 custom Sierra Horizon speakers. The quality of the bass that they produce is so good that I am seriously considering crossing them over as low as 40Hz, even though I have a pair of SVSound PC13-Ultra subwoofers!

But for that last octave from 20Hz-40Hz, there's no good reason to try and force the Sierra Towers or Horizon to play that low.

I know there's a thought that if you set them to "small" that you'll somehow be "missing" something. Well, the only thing you'd be "missing" is that last octave below 40Hz, where the speakers are steeply rolling off, and not really able to maintain the same output levels anyway. So why push them? Why potentially abuse them? The vast majority of what we hear and consider to be "bass" is above 40Hz anyway. All of the really fun "hit you in the chest" tactile bass is in the 40-50Hz region, which the Sierra Towers can handle just fine! All you're "missing" is the "blur your vision, rattle your teeth" ultra deep bass. And that's what a great subwoofer (or two, or four ;) ) is for!

So, rather than asking, "can I safely play the Sierra Towers Full Range?", I think the better question is, "Is there any good reason to NOT run them as "small" with a 40Hz crossover?"

Set to "small" with a 40Hz crossover, the speakers will be happy and safe, and you'll be blown away by the quality of the bass that they produce down to 40Hz! That is definitely the way to go, IMO. Naturally, once you own a pair, you can experiment, and try setting them to "Full Range" for yourself to hear if there's really anything worth while below that 40Hz mark that you'd consider it worth even the slightest chance of damage from an over-aggressive EQ. But, for my money, I'd always just set them to "small"; with subwoofers in use, I'd probably use a 60Hz crossover. But, like I said, the bass is so darn good from the Sierra Horizon speakers that I might even set them to 40Hz, even with subwoofers playing along side them! With no physical subwoofers playing, though, I'd definitely set them to 40Hz, and enjoy them worry-free :)

[HEPD85]

you, my friend are a genius, what you described was perfect for what I had in mind, thank you very much :)

[DevL]

you, my friend are a genius, what you described was perfect for what I had in mind, thank you very much :)

Keep in mind that ANY speaker will produce output at 20 Hz... its just reduced due to driver limitations. Also keep in mind that ANY cross over does not cut out all the 20-40 hz material. All it does is decrease the output, just like the speaker naturally does. A crossover only cuts say 12db per octave for 2nd order. So you can have the speaker naturally cut off a X number of db per octave on its own or X number + your cross over order.

The question is what exactly are you accomplishing by using a 40 Hz cross over? I would submit nothing is accomplished other than a reduction in sound you would like to hear. Audessy (at least how it is implemented in my XT 32 version) does not boost the frequencies below the cut off it predetermines during set up.That is just a myth perpetuated by people guessing at possible issues with no data to back it up.

Run your speaker full range and don't worry about it. The 40-16 Hz material will still be there, just not loud.

[RicardoJoa]

There is a difference between movie and music. With music, i dont think there is much to worry as there isnt a whole lot down low and it is not supposed to have boost in CDs recording in the low frequencies. As with movie, i think there is a boost added to the low frequencies. What is important is not frequencies below 40 hz, but below the port tunning frequency. Below tunning frequecies the bass driver will act like in a free air and it will move abrutly which may caused damaged to the driver.

[GirgleMirt]

I have a pro power amp an it does come with a low fr filter, either 40 or 30hz, can't remember. I have it off, always running fullrange. My logic is that even if there's not a lot of low bass output, if you're running fullrange, might as well get what you can in terms of bass extension. By cutting down the low fr, you are limiting the speakers, and worse, the filter will often affect upper fr, as say 45 or 50hz might get affected by say one or two db...

Anyhow, with a speaker like sierra towers, you're not really hurting the speaker by running fullrange. I'd say the same for sierra monitor, but, depending on volume, the single woofer might strain producing bass + mids. But either way, it's a compromise, sacrifice bass extension for marginal mid improvement? Certainly more an issue than the towers, as the dedicated mid and twin woofers are entirely different beasts. So i'd say don't bother with the towers! Just running fullrange is fine. Just be careful not to have auto-eq boosting low fr. Just how loud are you running anyway? IF you ever end up pushing the speakers fullrange, beyond it's capabilities, you'll hear it.

It also depends how you use the speakers though... The pro amp is most usually used in pro settings with pro monitors, which are often quite large and efficient and have very high power handling; are made to play really really loud. In that setting, the filter makes a lot more sense than in my house, where I don't play the speakers as loud, and so the risk and effect of the filter is rather different...

[davef]

Audessy (at least how it is implemented in my XT 32 version) does not boost the frequencies below the cut off it predetermines during set up.That is just a myth perpetuated by people guessing at possible issues with no data to back it up.

The problem is that Audyssey often gets that cut off point wrong. For example, it often sets the Sierra-1 as large (full range) depending on the room and in this case, it does boost low frequencies.. Manually setting the high pass -3dB point, based on the speaker manufacturer's suggestion (not what Audyssey measures in the room) is key...

That stated, running the towers full range is certainly not an issue. We run them full range in our demo room nearly all day, every day.. But we do not use any EQ.... The real issue with EQ boosting low frequencies is the demand it then puts on the amplifier section. Let's say, for example, you have a 100 watt receiver. If the EQ adds +3dB gain at say 35 Hz, while you "think" you have the potential to supply 100 watts of power to the speaker, your amplifier has now become limited. If you are hitting 100 watt peaks in the midrange, with the +3dB boost, you are now demanding 200 watts from your receiver in the 35Hz range. Your receiver can not do it, it will send out a large amount of distortion and cause problems, often damaging woofers.... Imagine if the EQ uses a +6dB boost?

The rule of thumb for any speaker is simple, if you hear mechanical distress, just turn the volume down and with regard to EQ, just make sure there is little to no boost below the port tuning frequency.

[Kisakuku]

The problem is that Audyssey often gets that cut off point wrong. For example, it often sets the Sierra-1 as large (full range) depending on the room and in this case, it does boost low frequencies.. Manually setting the high pass -3dB point, based on the speaker manufacturer's suggestion (not what Audyssey measures in the room) is key...

While it is of little consolation to the end user, there's a somewhat logical explanation for this. Audyssey actually does not set crossover values; it simply takes frequency response measurements and reports them to the AVR. Only the AVR manufacturer has control over how the crossover value is set. Many of them set the speakers to LARGE as long as there is some response below 80 Hz. The bottom line is, regardless of the suggested settings, always change speaker settings to SMALL and the crossover value to an appropriate frequency above the suggested crossover value.

[HEPD85]

Thanks everyone, i really appreciate all the responses, it's been very educational so far :)

[sourbeef]

jonathan teller, I like the way you think.

[Peabody]

I know this thread is a couple of months old, but maybe someone is still following and can answer an additional question. I'm very new to the audio hobby, and I'm learning a lot from discussions like these.

I believe I understand the point when the Towers are run in a HT setup with an AVR with speaker size and crossover set. I'm curious though, if the Towers are in a 2 channel setup with an integrated amp and no settings for speaker size or crossover, then what happens with frequency information below what the speakers are capable of? I think this kind of goes back to the OP's original question. Is that frequency info ignored or will the speakers try to play, say a loud deep organ note below 30 Hz? Will this damage the woofers?

I plan to use my Towers in a 5.1 setup with an AVR, but I might also like to try them in my small dedicated stereo room with an integrated amp.

Sorry if this is clear to others, but I'm still learning. Thanks!

[petmotel]

I know this thread is a couple of months old, but maybe someone is still following and can answer an additional question. I'm very new to the audio hobby, and I'm learning a lot from discussions like these.

I believe I understand the point when the Towers are run in a HT setup with an AVR with speaker size and crossover set. I'm curious though, if the Towers are in a 2 channel setup with an integrated amp and no settings for speaker size or crossover, then what happens with frequency information below what the speakers are capable of? I think this kind of goes back to the OP's original question. Is that frequency info ignored or will the speakers try to play, say a loud deep organ note below 30 Hz? Will this damage the woofers?

I plan to use my Towers in a 5.1 setup with an AVR, but I might also like to try them in my small dedicated stereo room with an integrated amp.

Sorry if this is clear to others, but I'm still learning. Thanks!

Yes the speakers will play the lower frequencies, just not in a linear response. Below the port tuning frequency, the sound pressure level will roll off naturally as frequency decreases. Towers have a typical in-room response of -3dB at 34 Hz, so they are capable of going pretty darn low, not a lot of bass they can not reproduce.

Stereo systems without low/high pass filters, or digital sound processing have been around for much longer than the more modern Home Theater surround systems which employ digital bass management, and room correction capabilities. So in the past, running speakers full range was the rule, rather than the exception.

Usually, if a speaker system is driven by an amp without enough power to drive them to the desired volume level, and the amp starts to send a "clipped" signal to the speakers, it's usually the tweeters that suffer the consequences, not the woofers. Probably, too little power is more of a danger to a speaker than too much. The Towers present an easy load for an amplifier, however, and will do well without a ton of power.

Main point to remember is: don't drive the system above the level at which distortion becomes audible, and you, and your speakers will be fine.

Towers are rated for 300 watts (continuous), I have them powered with an amp rated at 225 watts/channel, and they go well louder than I care to listen. Both systems have a sub, but I sometimes play the stereo system full range without the sub. I play them pretty loud sometimes, and I definitely love good, strong, low bass!

Jay

[Peabody]

Jay, thanks for the further explanation. Very clear, and I get it now. I particularly liked the the key point in layman's terms:


Main point to remember is: don't drive the system above the level at which distortion becomes audible, and you, and your speakers will be fine.

My stereo integrated amp is rated at 80 watts/channel, and in the small space (10 x 11), I don't need to play it very loud to be completely satisfied. So I probably have nothing to worry about, but I will be careful to avoid any clipping.

Mike

[mapmn006]

OK so I want to listen to the difference between full range and having my speakers set to “small” with 40hz as the crossover...

Does it make sense that after I run Audyssey XT on Denon 3313ci it sets the speakers (just 2 towers) to “large.” Than when I manually change the setting to “small” with the crossover at 40hz it changes the Audyseey setting to “off” and only allows either “off” or “Graphic EQ”. The other two options are “Audyssey” and “Audyssey Flat” when in “large” setting. So I have two setting options in “small” and all four when in “large” The way I'm taking this is you can only use Audyssey room correction when speakers are set to “large?”

The four (two) settings are all under the audio>Audyssey>MultEQ XT heading.