Large vs Small, Reference Level on Sub (1 Viewer)

[David Sailor]

Here's my first post, I considered adding it to Edward's fine thread re: pb2 but decided to start a new one since the only relation to that thread is I will also be the owner of this fine sub, ordered on 7/18 and the wait begins.

My questions: Regarding large vs small, at what size do you decide to set to small, I have seen references that all speakers are set to small when a quality sub is used. On the other hand, my main speakers are Paradigm studio monitors, should they qualify for small? The surrounds are the Titans and I would expect them to be set small, same for the cc 350 center channel. What's to gain by setting the monitors to small?

Secondly, research seems to indicate that if all speakers are set to small, then the sub is expected to play to 121 db, I think, to make up for the lack of bass in the other speakers. What adjustments are made to the sub in this case? Is it set higher so that it's several decibels "hotter" than the other speakers? Sorry for what may be basic questions and the length of the post but am getting anxious to establish good settings when the pb2 arrives. BTW, the electronics are all Adcom, 200 wpc to all speakers. Thanks, David

 

[Robb Roy]

David,

A PB2+ is going to play lower and louder, with less distortion, than your Paradigms (That's not a knock on your Paradigms -- not a whole lot of stereo speakers are going to keep up with an SVS in the bass department). You also reduce the risk of cancellation of deep bass, and let your Paradigms work in frequencies where they are less likely to have distortion. That said, you can try it both ways and keep it the way you like best (you're listening to it, not me).

When calibrating, most people tend to calibrate hot for two reasons: 1) by accident -- a lot of people don't realize their SPL meter reads bass a tad low, and our ears are even worse, and 2) because we like it -- since we really don't like to listen at reference levels, but still like the deep bass (that our ears are less sensitive to) and the corresponding tactile information, we play it a bit hot. Like the previous answer, it depends on what you like. If you had the fine sense to get a PB2+, I'd guess you like bass.

-Robb

 

[David Sailor]

Good point, set them all to small or experiment with the studios at large, see how it goes. I take it that the studios set to small will play cleaner since no effort is wasted trying to reproduce frequencies it's not capable of.

When setting all speakers to small, the pre/pro then directs the low frequencies that were normally to go the the surrounds/l/r/and center to the sub. Does that in itself cause the sub to play louder? That is, to compensate for the extra db required for reference level? Like most, I won't be playing at that level, wife and 3 kids not likely to consent, just want to understand and shoot for a proper setup.

Robb, thanks for the reply and, like you said, I can listen at my own preferences. I'm aiming at getting a proper baseline then going from there to adjust for room considerations, preferences, etc. Thanks, David

 

[Edward J M]

When setting all speakers to small, the pre/pro then directs the low frequencies that were normally to go the the surrounds/l/r/and center to the sub. Does that in itself cause the sub to play louder? That is, to compensate for the extra db required for reference level?

That is correct. Dolby Labs defines reference level as 105 dB bass peaks in any surround channel, and 115 dB bass peaks in the LFE channel.

If you had truly full range speakers in every surround channel, you could run them all on large and the sub would just handle the LFE channel.

The vast majority of enthusiasts do not have true full range speakers all around, so they high pass them and let the sub handle both low passed bass and the LFE channel.

The 121 dB number is derived from the supposition that there is a simultaneous bass peak in the LFE channel and in the surround channels. The combined sound pressures from the surround channels (105 peaks) and the LFE channel (115 peaks) could in theory require the subwoofer alone to produce upwards of a 120+ dB bass peak if all the speakers are set to small. Then factor in someone who runs the sub a few dB hot at the outset and now you are talking 122-123 dB bass peaks.

I have found that the mastering level of DVDs is so all over the board that it is virtually impossible to have one Master Volume setting that produces "reference level" playback volumes. The reason we all calibrate to a baseline benchmark like Avia or VE is so we can compare playback levels for a given DVD.

Regardless, unless your mains can extend clean down to 20 Hz at high volumes, you are better off high passing all your speaks at 80 Hz and letting a world class subwoofer handle the bass chores.

This article IMO is one of the best on this subject; give it a read and see what you think.

http://www.hometheaterhifi.com/volum...rs-9-2002.html

Regards,

Ed

 

[David Sailor]

Ed,

That indeed is a good article. After reading it a few times, I'm still digesting it but the gist is what you said, i.e. set all to small and let the sub do the work. I think my initial reaction is "I have full range speakers, why waste the lower frequencies, or Why did I buy full range speakers in the first place?" That was before I had a sub, actually I don't have a sub now, waiting on the pb2 plus order. The article indicates that the mains should play cleaner with out being burdened by the lower frequencies. The last time I tested them with the Avia disc, they played down to the high 20's so it makes sense to bypass them. Thanks again, David

 

[Edward J M]

I don't have a sub now, waiting on the pb2 plus order. The article indicates that the mains should play cleaner with out being burdened by the lower frequencies.

That is correct. The amps don't work nearly as hard, nor do the speaks, particularly the woofs (obviously). The improvement in dynamic range and midrange clarity, and the reduction in harmonic and intermodulation distortion are often quite noticeable.

With a PB2-Plus in the loop, you have the makings of an OUTSTANDING system for both HT and music. I continue to be floored by the excellence of the PB2-Plus for music.

Regards,

Ed

 

[Steve_Wingman]

David,
Trust your ears also, if it sounds good to you go with it.
This goes against the rules but...

My setup:
Yamaha RXV 496
Paradgim Monitor 9 main, set to large
CC370 set to small
PDR8 sub, xover rolled off to about 1/2 (no numbers)
(LFE set to both main+sub)
Titans rear, set to small

Before I bought the 9's I had the Titans up front set to small with the sub xover maxed, the midrange all ways sounded flat.
I tried the 9's as small but liked the large setting & blend with the sub better. Maybe with a bigger sub this would change but for music (85% of my listening) this works for me. Not earth shaking in movies but acceptable.
-Steve

 

[David Sailor]

I'm anxious to get the sub and start experimenting. My hope is to get enough information in order to have a working reference point. That way, if I make too many adjustments and don't like it, I can always default back to the beginning. I guess my truck is sort of the same way; after the install of the speakers, amp and subs, we set crossovers at normal levels and then went from there for personal adjustment. I guess that there is a good argument for smaller mains if a good sub is used, allowing the mains to produce the frequencies they are best at and allow the sub to reproduce the low signals. David

Steve- There are surprising similarities to our speakers, thanks for the input.

 

[Mike Sloan]

David, when you set your Paradigms to small...you are not "wasting" there full range ability. They still output freq. below 80hz due to the nature and slope of the receivers crossover. A full range speaker sounds fuller than a sattelite (ie M&K150) when set to small! There are many people running the B&W802's in small....because it sounds better!

 

[David Sailor]

Mike,

Thanks for your response. I think you have hit an underlying issue I have, i.e. did I make the right choice to have large studio monitors for the l/r? I can't help but feel that setting them to small is such a waste, but everyone's responses indicate otherwise. The technical report linked above by Edward is very compelling. Thanks all, David

 

[Mark Seaton]

A few points-

First, it should be remembered that the numbers being thrown around such as 105dB for the mains, 115dB from the LFE, and potential of >121dB for re-directed bass+LFE is that these numbers are at the seats! To achieve these levels at the seats you mains will likely be required to produce at minmium 110-115dB @ 1m. A smaller room can help the sub quite a bit, but it still needs to produce a LOT to achieve such levels.

So far as reference levels, the concept is to enable us to hear what level the soundtrack was mixed/engineered at. Reference level does not mean you will hit full scale on the DVD, but rather that at reference, full scale would produce 105dB at the seats from the mains, and 115dB at the seats in the LFE.

With respect to setting main speakers to small, the first requirement is that your subwoofer can produce cleaner/louder bass than your mains. If so, with any speaker containing dual 8" drivers or less, a 60-80Hz crossover can still make full use of your main speakers if you want clean dynamic levels. Most underestimate how much "woofage" is required for even 80Hz. A pair of sealed 6.5" woofers might barely meet the needs in most rooms. As a simple test, pop in a soundtrack like LOTR and watch the woofers in your center channel and mains. You might be suprised at how hard you can get them working even with an 80Hz XO.

Regards,

 

[David Sailor]

Mark,

This next post is up your alley, then.

Keeping in mind what you just said, here are some specifics: I have Paradigm's Studio Monitors. The pre/pro coming in (on order) is an Adcom 860. I just checked and here are the bass mngt settings for this unit: Either all large, all small or large to the main l/r, small to the center/surrounds. The crossovr point is 100 hertz, non-adjustable. I'm inclined to set them all to small given all of the above posts. So's here's my concern: I'm I wasting the studio monitors by only sending them signals above 100 hertz? I'm less concerned now but am interested in input. Secondly, will the pb2+ have any issues w/a 100 hertz crossover? I called Erik at SVS today and he was comfortable with that crossover point. He was confident in his assessment and I have no reason to doubt him. In fact, without even having an SVS yet, I can wholeheartedly recc'd them on support alone! The link that Edward posted above indicates that at 100 Hz, the crossover may not be as seamless at it would say, at 80 Hz.

I'm not trying to beat a dead horse here, I have learned a lot from these discussions and very much appreciate the input. Also, at this point, this is still very much academic to me, I'm currently running my system without the 860 or the pb2+. Once here and installed, I'm sure I'll have a different outlook and questions. David

 

[Lewis Besze]

David,
since the crossoverpoint is not adjustable you have only those 2 options you mentioned,unless you add other hardwares like the Outlaw ICBM.

Ask your self these question,the answers might help you decide yourself.

Do you listen at near reference levels?
Which speaker do you think handles bass better below 100hz?
Which amplifier would have more headroom to handle large bass transient peaks?
Could redundant bass info from both the mains and sub interfere with each other[cancellation of certain frequencies]?

I'm I wasting the studio monitors by only sending them signals above 100 hertz?

You're definitely sending signals below 100hz,however it depends on the crossover slopes as how loud.The typical 2nd order[12db/oct] they use on high-pass signals,the output will be down by 12db at 50hz[provided there are no room modes to interfere],so you mains are still "covering" a substantial area of mid to upper bass frequencies.

 

[Steve_L_B]

Okay, now I have a question. If one sets the mains, center and surrounds to small and high passes them at 80Hz and also sets the sub low pass cutoff to 80Hz, isn't a notch created at 80Hz? I'm assuming that 80Hz is the -3dB point of each of the filters.

It seems that one should have a slight overlap between the filter cut-offs to achieve a flat response.

Is this the case? If so, how much overlap?

Regards,
Steve

 

[Robb Roy]

Steve,

If you set the crossover on your receiver, you want to disable the crossover on your sub. If that is not possible, set it as high as possible.

-Robb

 

[David Sailor]

Lewis,

Good questions, no on the reference level listening. From time to time, not regularly. Your other questions would lead me to think that the sub is better suited for that work. I'm at a point where I may not get the Adcom 860 and look at something else (fodder for another post) but there's no way I'll give up the pb2+. Maybe I'm holding out for another processor that has better bass mngt for nothing but I had my doubts on that particular unit anyways. David

 

[Lewis Besze]

David,
I've had the Outlaw 950 since it's introduction,and I don't have any itch to upgrade to one of those multi kilobuck pre/pros out there. It's performance and features[including variable HP/LP points] are still satisfy me,and it's current price is really a bargain IMO.
Good luck with your search!

It seems that one should have a slight overlap between the filter cut-offs to achieve a flat response.

It's usually done with different slopes.The LP[sub] normally has twice the value of the HP[mains]filters.

 

[Arthur Vino]

thanks, good to know.. Does PB2+ allow u to disable the crossover?


>If you set the crossover on your receiver, you want to disable the crossover on your sub. If that is not >possible, set it as high as possible.

>-Robb

 

[Robb Roy]

The PB2+'s crossover has a bypass setting.

-Robb

 

[Edward J M]

Lewis is right on. The LP filter is steep to prevent the sub from playing much above the selected crossover point and being easily localized.

Some people have all sorts of trouble getting a 2nd order HP and a 4th order LP to transition well. Personally, I have never had a problem, as long as the phase control is dialed in and the sub and the mains aren't competing at the crossover point.

With the phase dialed in, my FR curves always keep a tight 1-2 dB variation at the crossover point. Reverse the phase, though, and it can become a 8 dB hole very quickly.

You are correct about the Adcom being a fixed 100 Hz crossover on small. The best pre/pros out there can not only alter the crossover points, but they have separate crossover point selection for each channel, and also can adjust the slopes of the HP and LP filters.

IMO, Adcom pre/pro's are not that strong for HT. I would at least look at alternatives that have better BM and also from looking at the Owner's Manual, it is unclear to me whether it can even decode DD-EX, DTS-ES, and DTS-ES 6.1 Discrete, instead relying on a home-grown DSP mode for the rear surrounds, similar to h/k's Logic 7. I would definitely check on this issue with a reliable source.

Also, unless your pre-pro has separate crossover points for each channel, you don't want to go any lower than 80 Hz for HT, because you will lop off the top of the LFE channel if you are using a subwoofer and all your speaks are set to small. The LFE channel can go up to 120 Hz in theory, but typically has no content above 80 Hz. But if you set your crossover over to say 50 Hz for HT, the content in the LFE channel from 50-80 Hz is filtered out and not redirected anywhere - it's just lost.

Arthur, the PB2+ does have a filter disable switch and you definitely want the switch in Disable mode if you are using the AVR or pre/pro for bass management.

Regards,

Ed