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07-01-2005 Post does not mapped to Knowledge Tree
skushino
Seattle, WA
Posts 93
Joined on 07-07-2004

Post #: 1
Post ID: 1125
Reply to: 1125
Sub-woofer integration with mains
In the past month I have been playing around with a sub-woofer.  This is my first experience with a sub.  Prior to this, I held a bias that subs generally cause more problems than they solve.  I am using a sub now because the main horns roll-off around 80Hz, and therefore bass reinforcement is necessary if striving for full-range performance. 

The sub arrived before the main speakers, so I practiced integration with my existing speakers.  They are rated full range to 20Hz, so I expected little change in performance.  Instead, what I noticed with the addition of the sub was two things:  1) better sense of acoustic space and 2) better HF playback.  The added bass was mostly noticed only when level (crossover and/or gain) was set too high.  The portrayal of acoustic space is very beneficial in my smallish 15' x 18' listening room.

Now, I'm working on integrating with the horn main speakers.  This is more difficult due to the higher crossover freq.  Question: Can anyone share a disciplined process to optimize the sub?  Placement, level, crossover, bass boost, phase, etc.  Without a disciplined approach, the combinations of variables is infinite.  How do tools like RTA figure into the process, vs using your ears?  I have done some experiements with placement, but size and weight deter me from endlessly moving the thing around the room. 

So how are you guys getting the most performance from your subs?

Thanks,
scott
07-01-2005 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,495
Joined on 05-28-2004

Post #: 2
Post ID: 1129
Reply to: 1125
Re: Sub-woofer integration...

 skushino wrote:
The sub arrived before the main speakers, so I practiced integration with my existing speakers.  They are rated full range to 20Hz, so I expected little change in performance.  Instead, what I noticed with the addition of the sub was two things:  1) better sense of acoustic space and 2) better HF playback.  The added bass was mostly noticed only when level (crossover and/or gain) was set too high.  The portrayal of acoustic space is very beneficial in my smallish 15' x 18' listening room.

Scott, I do not see anything extraordinary. What you mentioned are some of the very normal benefits of using a LF dedicated channel (I tend do no use work subwoofer)

 skushino wrote:
Now, I'm working on integrating with the horn main speakers.  This is more difficult due to the higher crossover freq.  Question: Can anyone share a disciplined process to optimize the sub?  Placement, level, crossover, bass boost, phase, etc.  Without a disciplined approach, the combinations of variables is infinite.  How do tools like RTA figure into the process, vs using your ears?  I have done some experiements with placement, but size and weight deter me from endlessly moving the thing around the room. 

As far as I understand you are using the Edgar’s Seismic Sub. It is OK unit (not without some cruel compromised). I do not know how are you planning to use it as you have just one of them and I am a firm believer that one LF source MUST NOT be used under any circumstances… and particularly at 80Hz. Get another unit and then you will be able to get a result worth something. Anyhow, to set up it properly, and particularly if you have no experience with it, there is no other ways then to use a 1/12dB RTA. I would have difficulties to comment on phasing and some other issues on this sub as this sub is time-wise completely screwed, as most of that type bass horns are. As I can recall Edgar used some kind of very high order filter in there with very heavy EQing the bottom response… So, only God know what is going on in there phase-wise and I would not worry about it. Besides, in the 15' x 18' listening room you have no leverage to manage it anyhow…. So, buy, borrow or steal an analyzer and then everything will be juts started….

Rgs,
The caT


 


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
07-01-2005 Post does not mapped to Knowledge Tree
skushino
Seattle, WA
Posts 93
Joined on 07-07-2004

Post #: 3
Post ID: 1130
Reply to: 1129
Edgar Seismic Sub
Hi Romy - Yes, the sub is Bruce's seismic.  It is big as a refrigerator, and the idea of having 2 huge boxes in this little room is, well, intriguing....  Being new to subs, isn't there an obvious danger of over loading this little room with too much bass energy?  Or is it more an issue of having 2 distinct sources for balance?  I don't think we're talking about stereo imaging issues at these low frequencies.

Regardless, before diving into the masochistic hell of trying to locate 2 gigantic subs, maybe it's a better idea to figure out how to use 1, properly.  If one sub is challenging, than 2 are more challenging.  My one sounds ok, but it's all over the board.  Sometimes too loud and booming, and sometimes like it isn't there at all.  Varies tremendously by program material.  Practicing integrating with my other speakers was way easier by comparison.  bty, the Seismic has a 4th order crossover ~70Hz, ~5 or 6 dB bass boost at 30Hz, and use a folded horn path. I know your (low) opinion of these tools, but it is what it is....

About RTAs, Bruce and my local guy, both advise that RTA "might" help, but just as likely lead on a wild goose chase.  They advise against the RTA.  But you know me, I'm kind of stubborn and may pick up an RTA anyway...
07-01-2005 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,495
Joined on 05-28-2004

Post #: 4
Post ID: 1131
Reply to: 1130
Edgar Seismic advise.

 skushino wrote:
Being new to subs, isn't there an obvious danger of over loading this little room with too much bass energy?
Where did you get this bogus notion? What does it mean: “loading this little room with too much bass energy”.  Do not repeat somebody else’s foolishness!
 skushino wrote:
Or is it more an issue of having 2 distinct sources for balance?  I don't think we're talking about stereo imaging issues at these low frequencies.
It is very much incorrect. The sources hold stereo information does to sub low frequencies and all stories that at certain frequencies only one LF sources might be used are juts the sick imagination of ignorant audio-reviewers or the mental defecations of audiophile with Audiogon intelligence. In addition, the LF sources MUST not be positioned BETWEEN the HF sources. How one would be able to accomplish it with one unit?
 skushino wrote:
Regardless, before diving into the masochistic hell of trying to locate 2 gigantic subs, maybe it's a better idea to figure out how to use 1, properly.  If one sub is challenging, than 2 are more challenging. 
Why? You ingrate LF module with of MF section. What the differents how many of them?
 skushino wrote:
My one sounds ok, but it's all over the board.  Sometimes too loud and booming, and sometimes like it isn't there at all.  Varies tremendously by program material.  Practicing integrating with my other speakers was way easier by comparison.  bty, the Seismic has a 4th order crossover ~70Hz, ~5 or 6 dB bass boost at 30Hz, and use a folded horn path. I know your (low) opinion of these tools, but it is what it is....
5 or 6 dB bass boost at 30Hz? I remember Bruce told at the Asylum that it had 15dB at 25Hz. I think it starts as 65hz and somewhere in the middle it changes to 35Hz bell. I do not remember. Whatever it is it is not bad and I generally like it, practically for the price.
 skushino wrote:
About RTAs, Bruce and my local guy, both advise that RTA "might" help, but just as likely lead on a wild goose chase.  They advise against the RTA.  But you know me, I'm kind of stubborn and may pick up an RTA anyway...
I do not know what motivated them to “advise against the RTA” as there are no other ways to do it. The only justification thing of their “advise” is that in your room with this LF module you have NO WAYS to do anything if something is incorrect. So, you get is “as is”. All the rest comes with a high resolution RTA. There is another reason why Bruce might advised you “do not go for RTA”: the 95% of Bruce’s customers are unspeakable Morons who do not need nether RTA not anything else. They are that Audiogon-Audioasylum intelligence that I mentioned before. Bruce knows it and he understands very well who his customers are and what result they get in their rooms. Consequently he does not even accustomed to deal with consumers who have bass demands more evolved then “loading room with bass energy”… Anyhow, you might borrow a RTA for a weekend for $100 and it will be a good investment. Then you might begin to educate yourself about bass… my estimate that it will take for you 3-4 month

Rgs
Romy the Cat




"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
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