Not getting powerful sound out of Tuba HT LP

[Jan-Kees]

...a few posts back I stated that the wooly sound is practically gone when I set the EQ on bypass. I think by the answer I got, that there was too much EQ corrections. And before that, the subs was out of fase with the main speakers, causing a muddy sound. But now it is better!
I still leaves me with the notch at 40hz and some smaller ones, and the question remains, can I correct those with the smallest Table Tuba, the one that rolls off after 38hz?

[Bill Fitzmaurice]

All one can say for sure is maybe. That notch is caused by the listening position. A second sub on the wall behind it may work. So would moving the LP away from that wall, which would shift the notch to a lower frequency. The rule for sub placement is either very close to or far from walls. The same applies to listening position. My sub is tight to the wall behind me, 35cm from my seat.

[Radian]

If I select THX crossover setting in the MC-8 processor, it sets all speakers to 80hz. So all speakers above the 80hz and sub below 80hz, the Lexicon takes care of the crossover transition right? With a overlap, which is normal.

No. Don't do that. It's not applicable because the system is not a THX specific setup.

[Jan-Kees]

If I select THX crossover setting in the MC-8 processor, it sets all speakers to 80hz. So all speakers above the 80hz and sub below 80hz, the Lexicon takes care of the crossover transition right? With a overlap, which is normal.

No. Don't do that. It's not applicable because the system is not a THX specific setup.

Okey! And what is specifiek about a THX setup? I will select the non thx 80hz then in custom setup menu, it has a slope of 24db per octave. (Long ago I had a KEF THX Reference Speaker set though!)_

You were talking about the different crossover points for speakers and sub, but the manual says:
• Select the subwoofer crossover point equal to the lowest crossover point of any of the other speakers

That is quite standard right?

[Radian]

You can research this, but in summary THX is a standardized spec for an entire assemblage of home theater equipment and techniques spanning from recording all the way up to and including the playback environment.

In this instance the speakers and listening space don’t align to the spec, so using any THX “default” settings won’t be ideal.

That is quite standard right?

Theirs is a generic starting point, and the wording is off. FWIW, I’ve got the same setup as you, and have measured nearly every curve and feature of the pairing. Suffice to say, catch-all advice won’t apply to such a high performance system.

[Jan-Kees]

You can research this, but in summary THX is a standardized spec for an entire assemblage of home theater equipment and techniques spanning from recording all the way up to and including the playback environment.

In this instance the speakers and listening space don’t align to the spec, so using any THX “default” settings won’t be ideal.

That is quite standard right?

Theirs is a generic starting point, and the wording is off. FWIW, I’ve got the same setup as you, and have measured nearly every curve and feature of the pairing. Suffice to say, catch-all advice won’t apply to such a high performance system.

Yeah, I know that about THX (all the way to sitting distance from screen...), but I just wanted to know what is different about THX speakers in regard to the crossover etc.

[Bruce Weldy]

You were talking about the different crossover points for speakers and sub, but the manual says:
• Select the subwoofer crossover point equal to the lowest crossover point of any of the other speakers

That is quite standard right?

That's the typical manufacturer advice - however, it doesn't take into account that the crossover isn't a brick wall. The volume decrases by XXdb/octave. If the speakers and the sub use the same crossover point, then there is a buildup on both sides of the crossover point causing a bump at the crossover point. By splitting the crossover frequencies and leaving a gap, the EQ curve is flatter before you have to start fixing it. I have a 7 hz split in my live system. Subs get 118hz and below, tops get 125hz and above. Still have to pull a little around that area typically.....but, it's much better than starting with all of that overlap.

[Old Mike]

I used to have an MC8 then an MC12. Neither will set the distance for a Sub correctly they will default the auto distance setting for the sub to same as the left front main.

Enter the sub distance manually and [you also need to allow for the throat length of the Sub. Start by adding 12 feet to the physical distance to the sub mouth. also as per someone else above use 40 or 50 Hz as the main and sub crossover frequencies. Change the sub distance in 6 inch increments to find the best performance using your built in microphones and processor otherwise known as ears and brain.