EQ Settings on Denon 4400 and narrowing down subs

[ryanosaur]

So leave the ports open, lower extension, lower tuning. Close the ports up, higher tuning. My reading that right?

And a sealed sub only has one variation of tuning to it versus ported and its different variable combinations?

And now you are getting into the complexities.
I don't have the experience with different subs to answer very well. I will use my subs as an example. Please understand, I do not expect all subs will operate on the same basic parameters as this, but my hope is this will give you a basic idea of how the EQ and ports work together on this particular model.
First, see here, page 8, for Outlaws description of the port and EQ settings. And here for Shady's measurements (and if you haven't, you should read the whole review, too!)
You have 3 port options, and 2 EQ options. EQ1 boosts the lower end, and EQ2 does not. That is my understanding, at least. Regarding the ports, you can see in Shady's graphs the tradeoffs in output vs extension, as well as the effect the EQ has on the response.
Hope that helps.

 

[shadyJ]

So leave the ports open, lower extension, lower tuning. Close the ports up, higher tuning. My reading that right?

It the opposite. In a multi-ported sub, if you close a port, that deepens the tuning frequency.

Subwoofer ports are 'Helmholtz resonators.' Helmholtz resonance is the resonance of air vibration in some cavity. It is the same effect that works to make a clean note when you blow over the top of an open bottle or jug. The driver is basically doing the same thing over the port in a ported subwoofer. It is very precisely vibrating the air inside that port, and that air's vibration is producing sound.

Ports interact with the air volume of the cabinet, and, like ryanosaur said, the larger the cabinet and port, the lower the tuning frequency. What makes a difference here is the ratio of the ports width by its length; a long, narrow port will have a much deeper resonant frequency than a short, wide port. So what happens when you have multiple ports in a speaker or subwoofer? They combine to act like one large port, but since the depth remains the same, they only act to 'widen' the port, thereby raising its resonant frequency. If you seal one of the ports, than you have effectively reduced the diameter of the port without reducing the length, so that lowers its resonant frequency.

Now what is the trade-off here? The resonant frequency is where the ports can generate the most output with the least amount of effort by the driver. So if the subwoofer has a port tuning of 25 Hz, it will be most efficient there and the surrounding frequencies. But ported subs have a very sharp drop-off of output below the port resonant frequency, so you can't count on much output below that point. So let's say you have a variable-tuned sub that has a 30 Hz tuning with 2 ports open and 20 Hz tuning with 1 port open. With 2 ports open, it will be able to play 30 Hz and above more powerfully than with it can with 1 port open, but with 1 port open it can play deeper.

 

[shadyJ]

Can you explain what you mean by “higher tuning” and “lower tuning”? Also, why does such a small decibel increase elicit such a steep increase in power output?

Ryanosaur answered this pretty well, but one thing I would add is that the needed power increase isn't necessarily to play deeper. Deeper frequencies don't need all that much amplification to hit the driver's maximum excursion. The trade-off here is that the subwoofers that aim for deep frequencies need to have drivers with a low resonant frequency to play deep stuff well. Well, a major way to make drivers have a low resonant frequency is to add weight to their moving mass, which is the cone, former, and voice coil. The problem with that is it becomes much less sensitive at higher frequencies, so it needs a lot more amplification to reach the same SPL as a lighter driver in midbass and upper bass frequencies.

 

[KEW]

Well, that's okay. I think either use DEQ or the AVR's Parametric EQ to boost the 20-80Hz for the Sub a few dBs and he'll be set.

One thing I will say (just like I said all those million times about DEQ) - Parametric EQ Bass Boost can be pretty awesome for music.

I had to decrease the subwoofer trim levels when I did the EQ Bass boost. Also used Q = 0.5, instead of 1.0 But man, the bass sound is great.

Oh, yeah, I don't mess with the treble EQ. Just the bass EQ.

1) How are you adjusting Q? Do the RBH subs have this option or is it somewhere else?

2) I just wanted to highlight the main difference between what Dynamic EQ does and what the AVR's parametric EQ does. The "dynamic" aspect of DEQ is that it changes in response to the volume level whereas the setting in the PEQ is fixed.
Note: I am going to be sloppy with specifics, but the general principals are sound - for example there is not a real reference level for music - it is not calibrated the way movies are, but just go with it.
So, you decide to listen to music this evening. Let us say that at reference level (-0dB) the balance of bass, mid, and treble is perfect w/o EQ (in theory, it should be close). However, you generally listen at -20dB. We know that at -20dB the bass will be weak and the treble weak (to a lesser extent). So you adjust the PEQ to get the optimal EQ for -20dB. Great, all is well and good! However, it is getting late and your child's bedtime, so you drop the volume to -40 dB so as not to run afoul of "she who must be obeyed". Now, if you are using PEQ, you either readjust or live with the EQ not being as good as it could. If you are using DEQ, the system will automatically readjust the EQ for the new level.
Generally, I would consider this a significant advantage for DEQ over PEQ.
Of course, I know ADTG has a large home and if his HT room is on the other end of the house from the kid(s) room(s), he may be able continue watching the movie without needing to lower the volume (or lower it only 5dB which will not cause the EQ to get too far off of target). If you always listen at the same level, there is no significant advantage to DEQ over PEQ!

General discussion of how to interpret the Equal Loudness Curve (for those who have not had the chance to spend time thinking about it yet):

Lets say we are listening to a String Quartet. Lets say the musician played at 90dB for the performance that was recorded (obviously no musician records at one SPL, but go with it). We generally assume the musicians are going to provide a good presentation, so they will automatically be adjusting the levels to maintain what we perceive as balanced levels across the frequencies.
Thus, for example, the String Bass will be plucking a 40Hz note much harder than an 80Hz note as a matter of routine so as to make them sound the same volume to the human ear (by the curve, they need to play 9dB louder at 40Hz vs 80Hz. So, while the 90dB curve is not very flat, the musicians are automatically matching the perceived sound levels at different frequencies by ear. The musicians are generally oblivious to this aspect of their performance, but have optimized the EQ for us for the level (SPL) of their performance!
If we take this recording and play it on our system at 90dB, we will get the correct EQ for the entire performance (and the sections where they drop to 40dB will also be fine because they EQ'ed everything by ear and we are reproducing it at the same level they played/EQ'ed it by ear)!
When we adjust the volume from 90dB to 70dB, we are attenuating the volume by 20dB across the entire frequency range, but if we look at the chart, if we attenuate 1000Hz by 20dB, for the sound level to match at 40Hz, it should only be attenuated by 16dB (instead of the 20dB it was lowered, meaning an EQ of +4dB is needed at 40Hz) and at 20Hz (generally not a big deal since music doesn't usually go this low) it should only be attenuated by 14dB (instead of 20dB,meaning an EQ of +6dB is needed at 20Hz).
You can see how the slopes increase (in the bass region) as the volume is lowered indicating more and more additional EQ is needed as the volume drops.

Side note:
In response to information such as presented by the chart above, in the 70's, Loudness buttons were a thing, but they were generally flawed because they were just a fixed EQ. This was a crapshoot from the get-go because without knowing the efficiency of the speakers that were to be used, they had no idea what the SPL would be! Furthermore, sales were generally better for the receiver that exaggerated the loudness and added ridiculous amounts of bass (which was impressive in the showroom), so manufacturers were rewarded for doing this wrong and it wasn't until the buyer got home and matured his awareness of a high fidelity system that he realized the loudness control was BS (smart in theory, but the execution had become crap)! Because of this, loudness controls generally fell out of favor and disappeared. Only Yamaha and a few others attempted implementations which varied the EQ as volume level changed!

 

[William Lemmerhirt]

@KEW, thought you might enjoy this chart. It’s what you already know in your mind but just graphed out. It’s how Deq is applied vs different volume levels.

 

[Steelers252006]

Ryanosaur answered this pretty well, but one thing I would add is that the needed power increase isn't necessarily to play deeper. Deeper frequencies don't need all that much amplification to hit the driver's maximum excursion. The trade-off here is that the subwoofers that aim for deep frequencies need to have drivers with a low resonant frequency to play deep stuff well. Well, a major way to make drivers have a low resonant frequency is to add weight to their moving mass, which is the cone, former, and voice coil. The problem with that is it becomes much less sensitive at higher frequencies, so it needs a lot more amplification to reach the same SPL as a lighter driver in midbass and upper bass frequencies.

Are there subs that do both well?

 

[AcuDefTechGuy]

1) How are you adjusting Q?
2) If you always listen at the same level, there is no significant advantage to DEQ over PEQ!

1. On the Yamaha PEQ, you set the Frequency, Q Level, and dB.
2. I always listen to the same volume level - back then with Denon's DEQ and now with Yamaha's PEQ.

 

[AcuDefTechGuy]

It’s how Deq is applied vs different volume levels.

I knew that DEQ boosted the bass, but I don't recall this graph.

I always set my speaker channel levels (Trim levels) so that my Master Volume was usually -30dB. So looks like the 30-40Hz got boosted 10dB+. No wonder the bass was great. Haha.

 

[ryanosaur]

Are there subs that do both well?

Hsu has good extension and strong mid-bass presence. You likely won't even be using your sub above 120 Hz for LFE effects, and probably above 60-80Hz in music listening. And as has been said before, most of the subs you've had recommended to you are all good subs. It almost comes down to personal preference of looks and design. (Not to minimize the minutiae of the performance specs!)

 

[shadyJ]

Are there subs that do both well?

The balance between deep bass performance and higher frequency performance is up to the designer. I would say that any sub that can hold a flat response from deep frequenies and above out to high output levels is one that has a good balance between deep bass and mid-bass. Many of the subs discussed in this thread have that quality. If you want to be sure, look at reviews with measurements of particular subs.

 

[Steelers252006]

The balance between deep bass performance and higher frequency performance is up to the designer. I would say that any sub that can hold a flat response from deep frequenies and above out to high output levels is one that has a good balance between deep bass and mid-bass. Many of the subs discussed in this thread have that quality. If you want to be sure, look at reviews with measurements of particular subs.

Tell me one more time why you think dual SVS PB2000s wouldn’t got the bill.

 

[shadyJ]

Tell me one more time why you think dual SVS PB2000s wouldn’t got the bill.

They might work for you. It depends on how loud you intend to listen. If you are not going to rock the house, they will do the trick. Personally, I would go for the PC-2000s over the PB-2000s, but that is me. Same performance, but lighter weight and smaller footprint.

 

[snakeeyes]

Are there subs that do both well?

HSU VTF15 is one

 

[Steelers252006]

They might work for you. It depends on how loud you intend to listen. If you are not going to rock the house, they will do the trick. Personally, I would go for the PC-2000s over the PB-2000s, but that is me. Same performance, but lighter weight and smaller footprint.

Yeah, I'm not worried as much about the weight, can handle that myself and got a few buddies to assist if not. I'm worried about the performance. Why do you think I could do better again? You say the Ultra Towers bass offering is on par with the dual SVS 2000s essentially?

 

[Steelers252006]

HSU VTF15 is one

My ONLY hesitation on that sub, and it may sound silly, is the fact that it is indeed priced so far below all the rest of the comparable type subs...makes me worry.

 

[snakeeyes]

My ONLY hesitation on that sub, and it may sound silly, is the fact that it is indeed priced so far below all the rest of the comparable type subs...makes me worry.

I don’t think you can go wrong either way but HSU is a great choice.

 

[William Lemmerhirt]

Yeah, I'm not worried as much about the weight, can handle that myself and got a few buddies to assist if not. I'm worried about the performance. Why do you think I could do better again? You say the Ultra Towers bass offering is on par with the dual SVS 2000s essentially?

I think he meant musically they might be on par.(but I don’t necessarily think that’s true)Those towers are pretty good to around 30hz iirc, but they are NO match for a subwoofer for HT.

 

[shadyJ]

Yeah, I'm not worried as much about the weight, can handle that myself and got a few buddies to assist if not. I'm worried about the performance. Why do you think I could do better again? You say the Ultra Towers bass offering is on par with the dual SVS 2000s essentially?

I would guess that, with proper amplification, your towers could probably match the PB-2000's mid-bass output, or at least come close. So it may be that getting some SVS 2000 subs, you are really only supplementing maybe 30 or 40 Hz and below. So you would be buying subs for a single low-frequency octave only. But I think that many of the other heavy duty subs mentioned in this thread could outperform the SVS Ultra towers in mid-bass frequencies as well as deep bass and so have a better value proposition when paired with that speaker, since they carry a very significant headroom advantage throughout their entire range. But, that is all just a guess. If it were me, I would be looking at subs with very powerful midbass if I had SVS Ultra towers. The SVS Ultra towers look to already have very good bass performance, so whatever sub you pair with them needs to have significantly better bass performance.

 

[shadyJ]

My ONLY hesitation on that sub, and it may sound silly, is the fact that it is indeed priced so far below all the rest of the comparable type subs...makes me worry.

The Hsu VTF15h sub isn't really that cheap. It's on sale right now for $859, but there is an additional $173 shipping fee. And you can also buy an extended warranty on the amp for an additional $70. So that adds up to $1100. and if you want the real wood Rosenut finish, that's an extra $200. It's still a bargain from a performance standpoint, but all of those additional costs are built in the price of other manufacture direct sub companies. You might be able to criticize them for not putting all of their costs upfront, but their subs are the real deal.

 

[Trell]

1) How are you adjusting Q? Do the RBH subs have this option or is it somewhere else?

Having a subwoofer with a wireless connection to adjust parameters is great. At first I thought that the Bluetooth was a bit of a gimmick, until I got two SVS SB-300 subwoofers and was calibrating.

First I calibrate using Audyssey XT32, and then use RoomEQ Wizard for further tuning using the three PEQ a SB-3000 has available. Without the SVS app the fine tuning would have been much more time consuming and inconvenient as repeatable moving two subs to get access to the controls located at the back is no fun.

2) I just wanted to highlight the main difference between what Dynamic EQ does and what the AVR's parametric EQ does. The "dynamic" aspect of DEQ is that it changes in response to the volume level whereas the setting in the PEQ is fixed.

For me DEQ is great and I would not buy a room correction that does not has a similar functionality, as I usually listen at volume at lower than -20 dB.

I only wish there was a way to reduce the level change DEQ applies to the surround speakers, mostly for use when listening to multi channel SACD where the increase in the level can cause the front stage to collapse (in the worst case).