Seaton Sound SubMersive1 - Page 265

Quote:

Originally Posted by cdnbum88 

The Denon has XT32 and the Marantz does not, but I thought the AS-EQ1 is giving me the equivalent to XT32?

The AS-EQ1 gives you the equivalent of XT32 for the bass frequencies only. If you use an AS-EQ1 with XT, you will effectively have XT32 for the bass and XT for the rest of the frequency spectrum. The bass is where EQ is needed the most. But bear in mind that Audyssey made changes to the way XT32 EQs the upper frequencies. In fact, they EQ them a little less - XT was apparently 'trying too hard' with the upper frequencies and could sometimes do more harm than good. So an AS-EQ1 is a very good addition to an XT system, but it is still not as good as XT32.

Quote:

Originally Posted by cdnbum88 

Thanks for input. This is more of a feeler thought as I am very happy on what the AS-EQ1 did for my overall HT experience, but to consolidate to ONE unit or maybe AVR + AMP would free up some room in cabinet.

I should know this, but would the AS-EQ1 work if I indeed get another HP into the mix or would I then be better off or need a unit like the 4311 with dual sub outs?

The EQ1 will EQ 2 subs in exactly the same way as XT32 (IOW it has Sub EQ built in), so in that sense it is neutral to your decision. IMO you would be best off if you had XT32 rather than XT + EQ-1 - I went exactly that route myself so I am very familiar with what XT32 gives you over and above XT + EQ1. But there is a cost involved to move up to XT32 and only you can decide if it is worth it. Taking money out of the equation, the answer is 'yes'. Factoring money in, the answer is 'maybe'. 

Hi guys,

I have just bought a Behringer DSP1124P to use its Parametric EQ abilities to see if I can 'ice the cake' on my dual F2s in-room response and also to perfect the splice. I am using REW to create the filters.

Question: do you think it is better to run Audyssey first and then use the Behringer to put the finishing touches to what Audyssey has done, or to do it the other way around and do the PEQ filters first and then run Audyssey?

This is my first venture into PEQ and I am not sure I can improve on what I already have, but as the 1214P was a very cheap purchase (bought it used) it's worth a shot. If I can’t improve things any, I will just re-sell the 1214P and stay with my current setup as determined by XT32 and Audyssey Pro. 

Any advice gratefully received.  Thanks.

Quote:

Originally Posted by craig john 

Quote:

Originally Posted by kbarnes701 

Hi guys,

I have just bought a Behringer DSP1124P to use its Parametric EQ abilities to see if I can 'ice the cake' on my dual F2s in-room response and also to perfect the splice. I am using REW to create the filters.

Question: do you think it is better to run Audyssey first and then use the Behringer to put the finishing touches to what Audyssey has done, or to do it the other way around and do the PEQ filters first and then run Audyssey?

This is my first venture into PEQ and I am not sure I can improve on what I already have, but as the 1214P was a very cheap purchase (bought it used) it's worth a shot. If I can’t improve things any, I will just re-sell the 1214P and stay with my current setup as determined by XT32 and Audyssey Pro. 

Any advice gratefully received.  Thanks.

Hi Keith,

I haven't used the Behringer device, but I have used the Velodyne SMS-1, (which is also an external PEQ), in conjunction with Audyssey. My experience in my own system was that running the PEQ post-Audyssey yielded the best results. (In fact, you have referenced that result in your FAQ.) That result was based on pretty decent pre-Audyssey FR, with no huge peaks or dips that Audyssey had to deal with. The SMS-1 was only used to tweak the final FR a few dB after running Audyssey. For that purpose, it worked extremely well.

However, in another system, I found that using the SMS-1 pre-Audyssey to reduce a huge 25+ dB peak was a significant benefit to the final Audyssey result, Without the huge cut implemented by the SMS-1, Audyssey was expending all it's resources to remove that peak and was therefore less effective at other frequencies. Audyssey has, (IIRC), about 9 dB of cut capability at any one frequency. If that is not close to enough cut for a huge 25+ peak, an external PEQ can be used effectively before running Audyssey to improve the response Audyssey "sees" prior to it's filters. The better the FR Audyssey is given, the better the final result.

In addition, and more importantly, the "Volume Normalization" process was negatively affected by this huge peak and lead to the well-documented ULF boosting. Reducing the peak with an external PEQ reduced the need for Audyssey to increase the overall level, which reduced the ULF boosting seen with the Volume Normalization process.

Bottom line, I think the best answer depends on the pre-Audyssey FR. If your system is pretty good to start with, Audyssey by itself can be highly effective, and the external PEQ can be used post-Audyssey to "tweak" the final result to good effect. However, if your pre-Audyssey FR has a single huge peak that dominates the response, the external PEQ can be used pre-Audyssey to great advantage to reduce that peak.

Craig

Craig - thanks for that I was hoping you might respond. That all makes sense and is very useful. In my system then I think the most benefit will be gained by running Audyssey first and then using PEQ as the icing on the cake afterwards. Audyssey does a pretty good job here and the room is well treated so it shouldn’t have to work too hard anyway. This is just an experiment which has come out of my continuing endeavours with REW (over at the 'REW Simplified' thread). If I cannot improve things I will re-sell the Behringer (bought for 70 bucks off ebay) and stick with Audyssey alone. My main endeavour ATM is to try to perfect the splice, which is the only thing that is not quite how I want it right now. I have much to learn about parametric EQing and HTS threads have been very helpful to me so far, as well as AVS of course. Deeper and deeper into the rabbit hole went Alice....

Quote:

Originally Posted by craig john 

Quote:

Originally Posted by kbarnes701 

Craig - thanks for that I was hoping you might respond. That all makes sense and is very useful. In my system then I think the most benefit will be gained by running Audyssey first and then using PEQ as the icing on the cake afterwards. Audyssey does a pretty good job here and the room is well treated so it shouldn’t have to work too hard anyway. This is just an experiment which has come out of my continuing endeavours with REW (over at the 'REW Simplified' thread). If I cannot improve things I will re-sell the Behringer (bought for 70 bucks off ebay) and stick with Audyssey alone. My main endeavour ATM is to try to perfect the splice, which is the only thing that is not quite how I want it right now. I have much to learn about parametric EQing and HTS threads have been very helpful to me so far, as well as AVS of course. Deeper and deeper into the rabbit hole went Alice....

Hi Keith,

If you are trying to improve the splice between the speakers ans sub(s), that presents a unique set of issues, and a parametric EQ may, (or may not) be the best tool. It depends on where the problem(s) are. If the problem(s) are in the time domain, then time aligning the speakers and sub(s) is the best approach for correcting those issues. I know you're already aware of the Subwoofer Distance adjustment technique to optimally time align the speakers and sub(s), and that is the first place you should start. However, if the issue(s) are in the frequency domain, (i.e., peaks and nulls in the FR from C & D interference), then the PEQ may be able to help... but only on the subwoofer channel. Remember that the PEQ is only applied to the subwoofer channel; it has no effect on the main channels. Therefore, if the problem(s) reside *above* the crossover, the PEQ will have little to no effect on them, (even if you set filters on the subwoofer channel that are above the crossover.) This may seem obvious, but it took me a while to recognize it with my SMS-1.

Nonetheless, if you are having trouble *above* the crossover, the first thing to try is a higher crossover. Re-routing that bass to the sub will change how it is "seen" by the room and how it is reinforced or cancelled by the room. It may be all you need to do. If that doesn't correct things, (or if it introduces localization problems), then the next thing to do is to find the offending speaker(s) and adjust their position(s) to alleviate the problems. Measure each speaker in isolation, with the crossover set, but without any subs. Then measure them again in pairs, (L + C, L + R, C + R), and then combined, (L + C + R). Look at the different roll-off points and the effects of the room on each speaker and each combination of speakers. Comparing those measurements may ferret out the problem cancellations. Once you have this info, you can use it to adjust the speaker placements to improve things as much as possible. However, if speaker placement adjustments are not possible, and the problems remain in the speaker channels, the PEQ won't help you, at least not much. (Re-running Audyssey using different mic placements *might* help as it will set different filter taps on the mains and subs.)

The only time the PEQ would be useful to fix things around the crossover splice is if the problems remain *below* the crossover. Then you can use the PEQ to adjust the subwoofer channel to try to improve things. Still, that's only one side of the splice and the PEQ can't do anything to the speakers, so you have limited adjustability there also. Bottom line, a PEQ is generally not the best tool for adjusting the splice between the speakers and sub(s), and should probably only be used a the "tool of last resort", when all else has been tried and failed.

Good luck.

Craig

Hi Craig - thanks for all that. The problem is below the XO. I have raised the XO already to 100Hz and am reluctant to go any higher, even if that would be a solution (if the problem was above the XO region). 

I have already done as much as I can with sub distance changes but it is not enough. WRT to speaker placement, there is so little opportunity for me there due to the very small size of the room. I realise PEQ might not be the answer, but for less than 100 dollars in total it seems like a worthwhile thing to try. I will keep the thread informed of my progress, or lack of it. I have a fairly steep learning curve to climb with the PEQ and REW's EQ section, but I am gradually, I think/hope, getting there.

Quote:

Originally Posted by craig john 

Quote:

Originally Posted by kbarnes701 

I have a fairly steep learning curve to climb with the PEQ and REW's EQ section, but I am gradually, I think/hope, getting there.

You're a fast climber, so I'm betting on you!

Craig

:)  Don't bet too much. And make it each way :)

Quote:

Originally Posted by Mark Seaton 

Quote:

Originally Posted by kbarnes701 


Hi Craig - thanks for all that. The problem is below the XO. I have raised the XO already to 100Hz and am reluctant to go any higher, even if that would be a solution (if the problem was above the XO region). 

I have already done as much as I can with sub distance changes but it is not enough. WRT to speaker placement, there is so little opportunity for me there due to the very small size of the room. I realise PEQ might not be the answer, but for less than 100 dollars in total it seems like a worthwhile thing to try. I will keep the thread informed of my progress, or lack of it. I have a fairly steep learning curve to climb with the PEQ and REW's EQ section, but I am gradually, I think/hope, getting there.

As Craig noted, the best tool and fix depends on the problem. If you post some measurements of the sub in isolation before Audyssey, post Audyssey, the center individually and the splice of the two that would be a great start. If you can add the results of distance adjustments, that would be even better. From your description it sounds like your issue might be dips that aren't quite filled in with Audyssey. This might be a case where PEQ before running could help a bit, especially with the headroom of the SubMersive above 40Hz.

Hi Mark, 

Thanks - I will post the measurement graphs you ask for later today. I think you have summed it up well - dips that aren't filled in by Audyssey is what I believe the problem is. Unfortunately, the dip is over a crucial frequency range - about 50Hz to 150Hz. I am going to re-run Audyssey Pro this morning to get a 'clean' Audyssey calibration and I will be able to give you measurements of the Audyssey-set sub distances and also my tweaked distances to try to improve the splice. 

I'll get back to you later. Thanks for taking a personal interest in this. Much appreciated.

Keith

Mark - here are, I think, the graphs you want to see. If I have missed anything vital please let me know and I will find them or make new ones.

It has taken some time. I re-ran Audyssey Pro today, using my 'previous best' set of mic positions - mainly clustered around the one and only important seat but with a couple on the other seat too. I use 9 positions in all. I am confident I am using Audyssey properly and that that is not the problem.

Audyssey set my sub distances to 10.6ft and 9.6ft. All references to pre-tweak distances are these. I experimented for a long time with different distances but without a lot of success. The best alternative I could manage with my centre channel + subs was 15.0 and 14.0 feet (all references to post-tweak are these). This gave a marked measured improvement for the C + Subs but was very detrimental to the R+L+Subs measurement. The best compromise seemed to be to go back to 10.6ft and 9.6ft (subs 1 and 2 respectively).  See if you can make anything of my graphs - my head is spinning. :) All full range graphs are 1/6th smoothed and all LF graphs are unsmoothed (except for one which is easier to understand with 1/6th, but is covered elsewhere unsmoothed too (I hope).. I really don't know where to go next or what to do next. I am hoping that the Behringer PEQ will allow me to smooth the subs out and then that that will help everything, including Audyssey. All the graphs have a description in them at the top.

Here goes:

I did a good listening test after finishing the graphs (using the pre-tweak settings) and it sounds terrific. I hope I haven't caught Graphitis Nervosa ;)  But I am sure there is room for improvement. Thanks for your help with this - it is much appreciated.