Why have full range speakers? Everybody just sets the crossover to 80hz anyways! (1 Viewer)

[Lee-M]

Phillboy,

No offense taken... if I was buying an all-new system on a budget, satellites would definitely receive serious consideration.

I would hate to think of the cost of replacing my Forte's... a modern equivalent would very likely cost in excess of 2-grand, a sum the Mrs. would most certainly be unwilling to part with in this leaner economy.

If money were no object, I would go with full-range all around, and dual subs... ah, to dream...

 

[Kevin C Brown]

Ain't nothing wrong with the Radio Shack meter as long as you remember to use the ubiquitously available calibration numbers, or at least keep in mind that it isn't as sensitive at reading low freqs as high.

And remember, for what most of us use it for: *comparing* different levels, it doesn't have to be *accurate*, it just has to be *precise*, which it actually is.

 

[Lewis Besze]

David,
Is that for home or cinema application?
Can you give a direct link?
In any case Dolby is the one who standardized the current bass managment system,but they weren't requiering it like THX does however.DTS on the other hand is very much pushing the equidstant full rasnge+sub scenario like the music industry.So in essence I wasn'r wrong since I never said Dolby won't recommend fullrange,I just said DTS is "bigger" proponent.

 

[David Judah]

Lewis,

What, you don't believe me? Go to #15 here.

I don't think we disagree. Like I said, although they say it's ideal, it's not very practical. Most everyone except maybe Widescreen Review uses bass management. It does make me wonder though. There are some folks who have mentioned that bass management is inconsistent in most decoders.

DJ

 

[Lewis Besze]

There are some folks who have mentioned that bass management is inconsistent in most decoders.

Yes I've heard those "charges",but I wonder what they actually mean by it.

 

[Kevin C Brown]

Yes, there is a certain infamous article over at Secrets that puts forth that most receivers and pre/pros with *multiple* crossovers do it wrong, but, a) they do not name a one of them, b) I know of at least 3 manufacturers that do it correctly, and, c) I only know of one that doesn't, but most people who have the unit also know that it doesn't because it's explained in the manual (or with the software upgrades) exactly how it works...

 

[RobD]

Im no where near as knowledgeable as you guys on crossovers and was hoping you could help me with a few sub woofer questions.

Im using Mordaunt 50X THX select speakers in 5.1 (Bi-amped fronts) with a Pioneer VSA-AX10I (Like the 49TXI in USA).

How do I make sure the two integrated powered subs are in phase?

The website list the mains as 32-22Khz and the others as 80-22Khz, is this figure of 80hz correct for the crossover setting? Or does it need to be set an octve higher as described above (Dont understand all of it).

The THX setting on the subs seems to work well although disables all volume and crossover controls on the subs themselves. What I dont understand is the bass peak manager in the amp menu, is it necessary for THX subs?

 

[Lewis Besze]

How do I make sure the two integrated powered subs are in phase?

Are these stand alone subs or built in to your mains?

 

[Lewis Besze]

Yes, there is a certain infamous article over at Secrets that puts forth that most receivers and pre/pros with *multiple* crossovers do it wrong, but, a) they do not name a one of them, b) I know of at least 3 manufacturers that do it correctly, and, c) I only know of one that doesn't, but most people who have the unit also know that it doesn't because it's explained in the manual (or with the software upgrades) exactly how it works..

Besides Lexicon, Meridian,and maybe Outlaw,I don't kow for sure what other manufacturer wouldn't fall into Brian's article's category.As he mentiones even THX don't mandate full LFE reproduction,independent of other channel's LP filters.
And certainly most manuals don't even try to explain this.

 

[RobD]

Are these stand alone subs or built in to your mains?

They are built in to the towers but are fed from the LFE out on the amp. These are them:
http://www.mordauntshort.com/products/502.html

Would Dolby reference be 0Db on the volume control? I dont tend to go past that unless the recording is too quiet. Melted a tweeter on one of the towers and had to have it fixed, have since avoided going past 0Db; especially after beverages.

 

[Mark Seaton]

Kevin wrote:

Ain't nothing wrong with the Radio Shack meter as long as you remember to use the ubiquitously available calibration numbers, or at least keep in mind that it isn't as sensitive at reading low freqs as high.

And remember, for what most of us use it for: *comparing* different levels, it doesn't have to be *accurate*, it just has to be *precise*, which it actually is.

I will agree that it works just fine for matching the levels of different channels. That said, the meter has been measured in the prosound community and while it is relatively close to it's spec for pink noise and broadband inputs, the frequency response does vary a good bit unit to unit, particularly at the frequency extremes.

Put it this way. While some have correction curves posted, I would bet that if we measured 10 different meters, the correction curves would differ for most of them. The weighting curves will be very close to the same within the tolerances of the electronic circuits, but the mic capsule does have some variation unit to unit. So, when looking at frequency response, I would say it not to be out of the question to see a +/- 2dB variance between units, which could be up to a 4dB swing.

So, I would not say that you shouldn't use it and attempt to get things in the ballpark, but realize that "flat" readings will not be quite flat, and some flexibility should be considered. Most significantly you should be making sure levels are relatively close near the top end/crossover point of the subwoofer, and make sure any large peaks are attenuated. My suggestion would be to not quite flatten them out, but cut them to only a few dB above the rest of the range- after using the correction factors.

In measuring more systems lately, I'm clearly seeing the benefit of a high resolution RTA or other swept signal measurement of suitably high resolution. The real response of the mains is quite valueable to see, and some unexpected settings can result in much improved response both measured and subjectively. One interesting option I have been looking into is a SuperLux measurement mic which I believe can be had for

 

[Lewis Besze]

Would Dolby reference be 0Db on the volume control? I dont tend to go past that unless the recording is too quiet. Melted a tweeter on one of the towers and had to have it fixed, have since avoided going past 0Db; especially after beverages.

First you need to calibrate your speakers with test discs like the Avia or Video Essentials,and need the affore mentioned Radio Shack Sound Pressure Level Meter,or something similar.I'm not sure if they sell those in the UK maybe they do under different brand name?
You need those 2 items first once you have it then pop in the disc which ever you bought and follow the information on the screen.
I believe there is a calibration FAQ on this board as well,and countless threads as well,search around.

 

[RobD]

Thanks Lewis,

I will try to borrow a sound meter to set to the dolby level. Can MCACC do this for me though?

Also Iam really confused about which speakers are large and which are small in my set. The spec says:
Fronts 32-22Khz
Centre 80-22Khz
Rears 80-22Khz

I rang the MS distributor who whilst very helpful told me the rears were large, which must be wrong and hence I dont really trust them. Im confused about if the fronts spec includes the subs or not. The speakers all use the same mid cones and tweeters and this is what makes me think maybe the front spec includes the subs in its frequency range. What do you think?

 

[Lewis Besze]

Also Iam really confused about which speakers are large and which are small in my set. The spec says:Fronts 32-22Khz
Centre 80-22Khz
Rears 80-22Khz

I would set the center and surround to small with the 100hz crossover option if the receiver has that.
For the mains however,I would rewire it,by removing the line level LFE connection,and use the speaker level inputs instead,so the speaker will act as one fullrange, not like sat/sub system.
In the speaker set up, set the mains to large and set the sub to "no" or "off".
In this case you simplify the connections and eliminate the chance to create sonic holes with missmathed crossovers slections.The reason for this, beacuse following the link you gave me for MS speakers,they don't disclose the built in sub's low pass filter value,they just say it's "defeatable".
So there you have it,good luck,let me know if this works out.

 

[RobD]

Thanks again Lewis,

I founs out today that the range for the L/R speakers includes the sub. These speakers are hence officially all THX general spec, all small and 80hz crossover.

Knowing this doesnt make the config you have suggested wrong though and hence I'm currently experimenting with both. There are three configs i will test with:

1) F:Small, C:Small, S:Small, Sub:Yes, C-Over: 80Hz, Switch:THX

2) F:Large, C:Small, S:Small, Sub:No, C-Over: 80Hz, Switch:Int

3) As 2 but C-Over: 100Hz

 

[Luke M]

To me, the ideal is to run all speakers full-range and use the subwoofer for the LFE signal only. This is, after all, how 5.1 was originally meant to be used.

 

[Lewis Besze]

To me, the ideal is to run all speakers full-range and use the subwoofer for the LFE signal only. This is, after all, how 5.1 was originally meant to be used.

Unfortunatelly most of us don't have the "ideal" speaker set up,with an "ideal" room to boot.

 

[Lewis Besze]

I founs out today that the range for the L/R speakers includes the sub. These speakers are hence officially all THX general spec, all small and 80hz crossover.

Yes I gathered as much too[regarding the front],that's why I recommended the large and no sub setting.If youe receiver properly reroutes the LFE info to the mains,then it should perform identically to the "small" and "yes" for sub set up.[80hz]If the rest of the speakers are THX certified then the 80hz should work,but it's smart to experiment like you said you will.

 

[Christopher_Ham]

Do you guys know if the Lexicon Dc-1 THX, dd , dts version 2.1 reroutes the LFE properly if set to "NO SUB"?
Thanks.

 

[Lewis Besze]

All Dolby decoders should reroute LFE to the mains per Dolby's mandate.There is a 10db boost on the LFE channel while it's being decoded,that sometimes gets' "lost" when rerouted to the mains.Years ago a buddy of mine and I conducted this test using a computer soundcard and a RTA program to determine on 2 receivers at that time.Sony 777 ES Denon AVR-3600,both dropped some of this "boost" when we rerouted the LFE channel to the mains,so the overall bass level dropped,though not by the full 10db,but nevertheless,some loudness were lost but not the content though.
You can experiment with this on your own gear,by using a RS meter.