Axiom Home Page Forums General Discussion Technical Questions DSP vs EQ

Yes, it certainly has a great thump that the 600 is missing but I was surprised that I got tired of it after a few minutes.

The 350 has thump too but it's not annoying. And my cheap Sony sub has a nice thump too that I really like.

Ever since you 1st mentioned the 'thump' issue, I've been paying close attention. While the EP500 and SMS-1 get fairly close to what I'm looking for, I don't know if I need a second sub, more room treatments, some more attempts at sub placement, or yet MORE experimentation to get what I want. It's a difficult puzzle to solve.

Your bass 'needs' appear to be similar to mine.. I don't however, have as many opportunities/means as you do to explore the possibilities...so I'll be eagerly lurking!

A second sub won't give you more thump unless it's a thumping kind of sub . The best advice I can give you is to get out and listen to more subs so that you can better understand what you may be missing. As for room treatments, I don't know what kind of treatment would absorb frequencies below 100Hz.

The most pleasing thump I've heard so far is from my cheap Sony. I get a lot of listening pleasure from the Sony paired up with the audiobytes. A close second is the EP350. All around, the 350 is a better sub though.

I was hoping by now that Randy would give us some more feedback on his EP600 equipped with the 150Hz filter. I've been waiting anxiously to find out if that leads to a touch more snap in the sound.

I kinda figured that dsp might be less costly. Maybe eq. is a lot more expensive?

Spoiler. I think a lot of us will be interested in how the PB13 performs.

The DSP is used to perform equalization within the sub components. EQ just means equalization, which is usually done using a DSP in your receiver.

I have 2 EP500's and my initial reads using REW confirm a large bump in the 60-70Hz range (+15db!). I think that this bump is causing a "false read" using Denon Audessy because even when I have the subs down to the 6pm position, the receiver still wants to take another 2db off. I just turn the level up on the subs afterwards.

The DSP in the subs can only do so much to adjust for the room. The EQ in the receiver can do a little more, but my receiver only has one adjustable band in the sub range (63Hz). I ordered a Behringer FBQ2496 last week online (new $135 shipped). It should be here this week, so I'll let you all know how a dedicated parametric equalizer helped out my situation. I already ran the REW analysis, and 6 filters in the sub range should get me to the +/- 1.5 db goal from 20-100Hz.

Keep us posted.

I'd like more info on your attempts, if you can spare the time:

1) What are your results when you turn on only one sub at a time? They might be cross-firing a tad too much.
2) Did you play with the sub's phases?
3) Did you try removing your mains from the equation and set their XO at 100Hz?

I was amazed that some of these humps are caused becuase my mains are the same distance from the side and front walls. Adjusting your mains so this is not the case, can help greatly. Also, moving them out from the front wall, and playing with toe in helps as well. It is not always the sub causing the humps.

The DSP cannot adjust for your room as it has no knowledge of its characteristics.

Mojo, you're right of course. What I meant to say was that the DSP can only do so much to produce a flat curve in a perfect room. Without the DSP, a sub's natural peak may be accentuated by your room's dynamics.

I have mys subs next to my mains, toed in. The drivers' centerline are about 2 ft off side wall, and 3 ft off front wall. I've tried moving them around, and it made some, but mot much difference to the response.

I have not tried one sub at a time, but I have tried adjusting phase. With one at 0 and the other at 180, the response was smoother, but much lower. With both at 180, the response again was similar to both at 0.

I've tried XO at 60, 80 and 100. 60 was too low, as there was a big dip between 100 and 60 (natural rolloff of the M80s I guess). Both 80 and 100 showed the peak in the 60-70 range.

After hours and hours of trying, this is how I have the Denon set now for "best" sound and response:

1) Denon Sub set to LFE+main
2) Denon XOs at 80 for all channels (and LFE)
3) Denon EQ in Manual (copied the flat curve over). I had to do this because Audessy insists on setting my M80s as large. Even when you manually switch them back to small, the bass still does not go to the sub. Manual EQ setting however allows it.
4) Subs both at 7pm gain position.
5) Subs set FLAT
6) Subs XO at 150 (bypass)
7) Subs at 0 deg (both)

With these settings, the sound is quite pleasant, but I can tell there is a bump in thr 60-70 range from listening. With the FBQ, I'm hoping to drop the bump down so I can increase the subs' levels to get a bigger gain in the 20-30 Hz range.