Crossover Frequency and DB level

[barun]

Hello Everybody,

I am a complete newbee to the forum and to the world of Audiophiles. I am trying to set up the speakers and the subwoofer to the right level but not succeding. There is something amiss. For eg if my volume is set at -20 which is kind of high (volume range is -80db to 0 db) it does not seem to be loud at all.

I give all the details that I thought will help you decide the right configuration for my speakers, subwoofers, crossover frequency and LFE.

These are the current settings and details that may be required.
Denon AVR – 2106
Speakers – Onkyo SKS-HT240
The ultra-stylish and slim Onkyo SKS-HT240 speaker package is a complete 6.1-channel home theater speaker package, including a 150 watt powered subwoofer. The powerful, full sound of this system is complemented by the unique modern design of the speaker cabinets -- sure to look good in any room, without taking it over.

100 Watt Power Handling (Front, Center and Surround Speakers)

Impedance: 8 ohm

Front Speakers: 3 1/8" Cone Woofer x 3, 1" Balanced Dome Tweeter

Center Speaker: 3 1/8" Cone Woofer x 2, 1" Balanced Dome Tweeter

Surround Speakers: 3 1/8" Cone Woofer x 1, 1" Balanced Dome Tweeter

Powered Subwoofer: 150 Watt Amplifier, 8" Cone Woofer, Auto Standby Function

Magnetic Shielding: (Front, Center and Surround Speakers)

Frequency Response: 27 Hz - 150 Hz (Subwoofer)

Frequency Response: 55 Hz - 35 kHz (Front Speakers)

Frequency Response: 65 Hz - 35 kHz (Center and Surround Speakers)

5.5 lbs. (Front Speakers)

5 1/8" x 19 11/16" x 3 9/16" (Front Speakers)

3.5 lbs. (Surround Speakers)

5 1/8" x 13 3/8" x 3 9/16" (Surround Speakers)

5.1 lbs. (Center Speaker)

17 5/16" x 5 1/8" x 3 9/16" (Center Speaker)

30.9 lbs. (Subwoofer)

10 13/16" x 20 3/8" x 16 3/16" (Subwoofer)

Room Size– 25ft – L, 15 ft – W, 10ft – H.

Date:May7th,2006

Speaker Level check
Front Left - -0.5db
Fron right - 0.0 db
Center - -0.5db
Surround Left - -0.5db
Surround Right - +0.5db
Surround Back - 1.5db
Subwoofer - -10.0db

May 8th,2006

Speaker Level check
Front Left - +0.0db
Fron right - 0.5 db
Center - -0.0db
Surround Left - -1.5db
Surround Right - +0.0db
Surround Back - +0.5db
Subwoofer - -10.5db

Delay
Front Left - 16ft
Fron right - 16ft
Center - 16ft
Surround Left - 4ft
Surround Right - 6ft
Surround Back - 8ft
Subwoofer - 19ft - The actual distance is 17 ft.

Speaker config check
Front Left - small
Center - small
Surround - small
Surround Back - small
Surround Back - 1sp
Subwoofer - Yes

Crossover frequency - 120 Hz

I will be grateful if you let me know what should be the ideal config or close to ideal. Please do not ask me to buy a SPL meter,audio CD's and do all the measurements. Right now it is beyond me - I have crossed the budget and also the amount of time I have spent on these things. I also note that my set of speakers are not the best and is 6.1 instead of 7.1 - budget restraint.

Will await eagerly for the comments and the config.

Thanks,

Arun

[Sonnie]

Hello Arun and welcome to the Shack!

I have a Denon 3806 and my volume really doesn't get loud until I reach about -10db. I can't imagine anything being wrong with having to turn it up to -10db or even 0db to get it loud as you want.

However... you can take your speaker levels and adjust them all upwards by say 5db... in other words your levels from May 8th would look like this:

Speaker Level check
Front Left: +5.0db
Fron right: +5.5 db
Center: +5.0db
Surround Left: +3.5db
Surround Right: +5.0db
Surround Back: +5.5db
Subwoofer: -5.5db


This will give you more range (and loudness) prior to reaching -20db.

[barun]

Sonnie,

Thank you very much. When I do a manual adjustment how do I save the settings? Also, if I switch off the AV receiver will the settings get lost.

Thanks, once again.

Arun

[barun]

Sonnie,

I more question. What should be the crossover frequency for the above settings? Do I need to tweak the LFE settings?

Thanks,

Arun

[Sonnie]

Well... it's hard to say with those smaller woofers in your mains and center, but they are rated down to 55 and 65hz respectively. Generally I'd say a minimum of one octave above the rated low end of the frequency, which in you case would be 110hz for the mains and 130hz for the center.

Why not change it from 120hz down to about 90hz and try it. See how it sounds and make sure at louder volumes your mains and center can handle it. If the mains and/or center seem to not be able to handle it or you notice any distortion, move it up to 100hz and then if need be back to 120hz.

[barun]

Hi Sonnie,

Thanks for the reply. But you missed replying to these questions - "Thank you very much. When I do a manual adjustment how do I save the settings? Also, if I switch off the AV receiver will the settings get lost."

I also wanted to ask you why you want the crossover frequency to be at the most 100 Mhz and not say 120 Mhz.
I did change the settings as suggested by you and overall there has been quite a bit of improvement but the bass has not improved at all. How can I improve the bass?
Also, you mentioned about small speakers - does it mean they are not good.What really is the difference between big speakers and the small ones except for the bass extension ?

Thanks,

Arun

[gsmollin]

Hia barun, and welcome to the forum.

I don't own a Denon, but if its similar to the Pioneer, settings are automatically saved, and are not lost when you shut off the AV receiver.

The crossover is rarely above 100 Hz, because the subwoofers rarely have any output above 100 Hz.

I imagine you want more bass... There should be a menu where you can adjust the levels of each speaker. There should also be a speaker setup menu, where you have test tones, or band-limted pink noise, and can adjust the levels of each speaker. I can add that AV receivers are one of those things that require a lot of study. Curl up with the manual and your remote, read, and then start trying out the menus.

The difference between big speakers and small speakers IS the bass extension. Some home theater front, center, and/or surround speakers have no response below 200 Hz. These types are usually about 4 inches or less across, and contain only a tweeter. Even small bookshelf speakers can be treated as large, if they are designed to handle a full range signal. One of the tricks of the HT speaker setup is to harmonize the fronts and subwoofer channels so that are adding to each other. At the crossover between fronts and subs, a phase notch can occur, where the two waves are out of phase and cancel each other. The result is a hole in the frequency response, and coloration of the sound.

So your choice for large or small is dictated by the results you get in the sound. Frequently, even large front speakers are set to small, to prevent a phase notch at the crossover frequency. However, with careful placement, and adjustment of the distance delays and/or phase control on the sub, you can get a smooth response.

Keep working on it, and you will get it right. it does take some time.

[barun]

Hello Gsmollin,

Thank you very much. I am happy to have joined the forum. It will help me improve my weak knowledge in this area.

Yes, I want to improve the bass.There is a menu where I can change the speaker config,delay, crossover frequency etc.
But what level do I set, what should be the comparative level between speakers or the subwoofer as a ball park which I can tweak a littile bit. You are absolutely right when you say that
"At the crossover between fronts and subs, a phase notch can occur, where the two waves are out of phase and cancel each other. The result is a hole in the frequency response, and coloration of the sound." That is exactly what is happening - causing me not hear the bass.
I do have the manual which is not very informative or helpful for the manual adjsutment. Any pointers might just help. I am totally new to this. I am just trying to learn from you guys and the forum.

Thanks, once again.

Arun

[Wayne A. Pflughaupt]

Please do not ask me to buy a SPL meter,audio CD's and do all the measurements.

Not to worry, you can get in the ballpark by ear.

I also wanted to ask you why you want the crossover frequency to be at the most 100 Mhz and not say 120 Mhz.

I agree with gsmollin, with speakers that have little woofers like yours have, you’ll want the crossover set high, since they probably don’t go much lower than 200 Hz. Set the crossover as high as possible. This usually isn’t optimal, as it lets you localize the subwoofer, but IMO that’s better than having a hole in the bass!

I did change the settings as suggested by you and overall there has been quite a bit of improvement but the bass has not improved at all. How can I improve the bass?

Going by the speaker settings you posted, you have the sub as the same level as the other speakers. That’s going to give you weak-sounding bass. People typically run the sub 10 dB or so louder than the main speakers. If the sub has a volume control on it, you can turn it up. Or, use the receiver’s sub level, if it can go higher.

Regards,
Wayne

[barun]

Hello Wayne,

Thanks. Yes, the speakers are rather small but I do get the higher frequencies. The frequency range for the speakers are as note below:
Frequency Response: 27 Hz - 150 Hz (Subwoofer)
Frequency Response: 55 Hz - 35 kHz (Front Speakers)
Frequency Response: 65 Hz - 35 kHz (Center and Surround Speakers). I do not know how they compare overall but certainly they are no where near the best.

I do have a volume control in the subwoofer but do not have a phase control switch. When you say the subwoofer should be 10db louder than the main speaker does it mean that if the main speaker is set at 0.0 db the subwoofer should be +10db.

Earlier I had set the crossover frequency at 120 Mhz but brought it down to 100 Mhz as suggested Gsmollin. I think at 120 Mhz the bass was better. Is 120 Mhz level not good for the main speakers or the subwoofer for a louder listening?


Regards,

Arun

[Sonnie]

Okay... sorry if I wasn't clear on that before Arun. These frequencies are actually in hertz (hz) not megahertz (mhz)... just to clear that up.

3" speakers are not going to produce deep bass at loud volumes... but you do have three in each main speaker and two in the center so this will help some... but they still ain't gonna produce loud and deep bass.

What I actually suggested was trying a lower crossover setting and see how it sounded. If you lost bass at 100hz then go back to 120hz or even higher if the bass gets better. What that means is your mains are not producing much below 120hz really... which may be about right for those small speakers.

Try this:

Speaker Level check
Front Left: +5.0db
Front Right: +5.5 db
Center: +5.0db
Surround Left: +3.5db
Surround Right: +5.0db
Surround Back: +5.5db
Subwoofer: -0.5db

Increase sub until you get enough bass to satisfy yourself. If -0.5db is not enough then move it on up to +5.5db. That would be 10db higher than what you originally had it. In the Denon... yes... once you set these and exit they are saved and you will not lose them.

You may have experiment with the sub setting until you get the right amout of bass you want.

[Danny]

Okay some of these may have already been answered but anyway. With speakers for low frequency's you want a large driver to move a lot of air and give you a really nice bass response. For high freq speakers they need to be small because of the rate at which they need to move to produce the HF sounds (eg 10000Hz = 10000 vibrations a second). Just using your ears without any fancy equipment you can normally get within 1-3 Db of a system calibration that was done with pro equipment, just listen carefully. If you have an Eq when setting it try to make the amount of cut and boost equal or very close to it, otherwise the louder sound will sound better to your ears. Crossovers in subs are used to eliminate the higher
'muddy' bass frequency's.

D.

[barun]

Hello Sonnie,

Thank you very much.I will let you know the results. I want to know whether increasing the crossover frequency means more lower frequency's are transferred to the subwoofer and in increasing beyond 120 Mhz whether it would affect the speakers or the subwoofer or not?

Regards,

Arun

[Sonnie]

Well... yes and no. Increasing the crossover means higher frequencies in the lower range are going to be directed to the sub. It may increase your sub response by enabling the sub to be able to play some of those lower frequencies that your mains can't play as well... but it does not extend the lowest regions of the sub bass. You got what you got there already. Increasing past 120hz may or may not help... you'll just have to experiment with it.

[Exocer]

I agree with everything mentioned above. But think about it this way. Your speakers have relatively small drivers. Automatically they're nature is to perform optimally in the higher frequencies. By sending these speakers as little bass as possible you improve their ability to shine at what they're good at doing, playing in a higher frequency range. Your main amp will have more power to provide to your smaller speakers when crossing over high. This is because bass takes power to produce. The power you send to those little speakers to produce frequencies that they're incapable of properly producing is nothing but a waste of useful headroom.

[jbarcelona4]

Hi,
I ran a test today using only my front paradigm 100 speakers, without sub. The reading showed that at 30 hz. I was reading 87 db. with a RS meter, the older one. The thing I don't understand about this is that my crossover is set at 80 in the pre amp. It seems to me between 20 and 70, the reading should be very low. Any suggestions as to what I am doing wrong.
Thanks,
Joe

[Otto]

Hi there,

Is it possible that your main speakers are set to "LARGE" in the "speaker size" setup on your receiver or pre/pro? My processor will not apply a high-pass crossover to any speaker set to "LARGE", although it will continue to apply low-pass crossover to the sub.

That'd be my first guess.

-- Otto

[jbarcelona4]

Thanks Otto,
That is the 1st thing I checked. I have all 5 presets in the Preamp set to small, for all speakers and the crossover is set at 80 from the preamp. The sub. is set to out. Thanks for the reply.
Joe

[Otto]

Hmmm. Could you perhaps be in some sort of "bypass" mode that ignores your bass management settings? Can you change "modes" (e.g., "stereo" to "dolby pro logic" to "5-channel stereo" or something like that)? Do these give the same results?

Also, how are you exciting the 30 Hz signal? With REW? A signal generator?

If your high pass filter is set at 80 Hz, there is still a roll off value. So it'll take some distance (in frequency) to drop the amplitude. Still, I think that 87 dB at 30 Hz is really high. What is your SPL measurement using the same setup at 60, 80 and 100 Hz?

-- Otto

[jbarcelona4]

Otto,
I tried the different crossovers, but at 30 Hz it didn't make a difference. I'm really lost on this one. I know there is a rolloff, but there must be something remiss in my preamp. I am still fooling with it and if I find a solution, I'll reply.
Thanks again,
Joe

[jbarcelona4]

I called Nad; I was told that in Stereo Mode the T163 Preamp would not have a crossover function. I would be the same as having the speakers set to large. As test did show, both speakers were playing full range. I later found that I could set the HSU Subwoofer to the IN position and the sub would not play after the crossover. Dr. Hsu recommended a high pass filter for the mains.
Joe