how to increase gain on sub? to keep up with LaScalas? insert headphone amp in line?

[tswei]

Howdy all. Been loving my new-to-me vintage LaScalas, but would like to boost the sub 50Hz region with an M&K Sub I had lying around.

Hooked it up to traditional line out of an integrated amp, but the Scalas are so effiecient, I cannot get sub to scale correctly as volume goes up. I've got the sub at max volume and the crossover set at 50 and it's barely audible.

SO what does one do if mains are super efficient and subwoofer is less so?? Maybe boost the signal a bit?

Would it help to but a simple pre-amp in the sub line? Or would that just max out at current level from the integrated. Could I insert a headphone amp??

[Dennie]

Hey Tswei, which integrated amp are you using? Can you turn the "trim" down on the LS's? I'm using a HT/AVR and can turn down each speaker indivually, so I have the sub at +10 and the LS's at -10 and uning the sub's volume control ( SVS 20-39 PC Plus ) I can get it dialed in.

Let us know the gear you're using and we'll try to help.

Dennie

[mustang guy]

You have discovered something. With efficient speakers, and an inefficient sub, no matter what you do when you turn up the volume, the LS's will pull away and you won't even know the sub is working. I had the same problem with my 6 LS's and a Paradigm DSP-3200, which aint no slouch. I ended up building a pair of Bill Fitzmaurice THT's.

Which M&K do you have, and how big is the room? There are plenty of subs that can keep up with LS's, but it takes some serious size or serious power when you want to listen at high volumes.

[Islander]

I'd recommend setting the sub's crossover/hi-cut much higher, at maybe 100-120 Hz. The La Scalas have very little output below 50 Hz, and they start to roll off at 100 Hz or so. Setting the sub at 50 Hz will fill in the very lowest bass, but the speakers need help above that point as well.

The exact numbers will vary a bit, depending on the characteristics of your listening room, plus most speakers will vary a bit from an ideal "standard La Scala". Try 120 Hz as a beginning, and see how it sounds to you.

My room is medium-sized, at 18' x 19', and is open on one side, plus I usually listen at low to medium volume, and rarely listen at high volume for long. In this situation, a 500-watt sub has worked fine, both for music and for movies at proper movie volume. At one point, I tried a pair of 100-watt subs, and found they were inadequate for anything more bass-heavy than acoustic folk music at low volume.

One way to increase the volume of your sub is to use a Y-connector to feed both the Left and Right inputs on your sub, if it has them. This can boost its output up to 6 dB.

[tswei]

Thanks for all the replies so far. islander, I agree that the Scalas roll off early.

I also listen at low/moderate levels, and at these levels I am sure that my sub can produce more output, the problem is the gain on my integrated is so small for the mains that the sub is not getting enough signal.

i am thinking of putting the sub out to a headphone amp and then headpnone amp out to the sub to add gain. Unless there is another way to add gain ONLY to the sub.

All the sub settings are maxed out already.

[Mongo171]

It just sounds like you don't have enough sub for the Scala's. Time for a bigger sub. Subs eat power for lunch. They need lots of it.

[Islander]

I agree that the Scalas roll off early. I also listen at low/moderate levels, and at these levels I am sure that my sub can produce more output, the problem is the gain on my integrated is so small for the mains that the sub is not getting enough signal. i am thinking of putting the sub out to a headphone amp and then headpnone amp out to the sub to add gain. Unless there is another way to add gain ONLY to the sub. All the sub settings are maxed out already.

With your sub set to start cutting off at 50 Hz, it's putting out only a fraction of what it can. If you turn up the cutoff to 100-120 Hz, its output should increase quite a bit, plus the sub/speakers combination will have a smoother frequency response. After making many test runs from 200 Hz down to 10 Hz with a test CD and an SPL meter, I settled on 150 Hz for the sub cutoff in my system. That gave the smoothest overall response, with the fewest dips and peaks.

I also use an equalizer to correct for a bass peak in the room at 32 Hz and a dip at 70 Hz. Sometimes dips and peaks are caused by the interaction between the speaker and the room and are not the fault of the speaker. Subs in particular can change their sound when you change their location in the room. It can take quite a bit of trial and error to find the best spot for the sub, and sometimes it's not in the convenient location you originally had in mind.

Also, feeding both Left and Right sub inputs should make a big difference in the sub's output.

What are the specs of the subwoofer that you're using? What size is the driver, how many watts is the amp, and is the enclosure sealed or ported?

[CECAA850]

It just sounds like you don't have enough sub for the Scala's.

Bingo.

[Quiet_Hollow]

With your sub set to start cutting off at 50 Hz, it's putting out only a fraction of what it can.

Not necessarily as that's not strictly a function of the LPF.

Meaning the inbound signal strength and the amp gain determine the final output...not the filter. The gain and freq knobs are intended to be set in unison. Adjusting one will require an adjustment of the other in order to maintain the intended crossover region.

Aside from the limits of the preamps and the gain factor of the sub amp, the LPF can be set all the way down to it's minimum freq and with a hot enough input, can still over power the driver.

Also, feeding both Left and Right sub inputs should make a big difference in the sub's output.

It's important to expound upon where this is coming from so people know this isn't a free lunch.

Using a y-cable parallels the load on the pre-amp..increasing the average power seen at the input of the sub amp. Good for a few extra dB at the expense of some headroom so long as the operator knows for certain they have no positive trim set in the AVR..otherwise the y-cable can increase the likelihood of clipping the pre-amp with a really hot signal.

[tswei]

It's not the greatest sub, an old M&K VX-1250. I was hoping that given I am playing low to moderate volumes that I could get enough output out of it. I am now worried about maxing/clipping the sub as I will never drive it that hard.

What I really want when funds allow is one or two of these:

http://www.rythmikaudio.com/F25.html

as I will be ultimately playing them in a 800 sq ft room with 9 ft ceilings. Right now just doing testing in my workshop which is about 12 x 15 x 9, mostly to see if I can get the full sound out of the Scalas that I want.

I like the idea of using a second input to the sub (which it can accommodate).

[Islander]

Also, feeding both Left and Right sub inputs should make a big difference in the sub's output.

It's important to expound upon where this is coming from so people know this isn't a free lunch.

Using a y-cable parallels the load on the pre-amp..increasing the average power seen at the input of the sub amp. Good for a few extra dB at the expense of some headroom so long as the operator knows for certain they have no positive trim set in the AVR..otherwise the y-cable can increase the likelihood of clipping the pre-amp with a really hot signal.

Using a Y-cable is explained in the instructions for the Paradigm PW-2100 sub that I'm using. It states that if you need extra output, this is a suggested option, which gives the impression that it won't cause any problems with this model. I did connect the sub like that at first, and thought the sofa would slide across the floor! I did not need that much output.

Connected in the usual way, the PW-2100 is rated at 500 watts continuous/1500 watts peak. It works well in my system.

[Islander]

It's not the greatest sub, an old M&K VX-1250. I was hoping that given I am playing low to moderate volumes that I could get enough output out of it. I am now worried about maxing/clipping the sub as I will never drive it that hard. What I really want when funds allow is one or two of these: http://www.rythmikaudio.com/F25.html as I will be ultimately playing them in a 800 sq ft room with 9 ft ceilings. Right now just doing testing in my workshop which is about 12 x 15 x 9, mostly to see if I can get the full sound out of the Scalas that I want. I like the idea of using a second input to the sub (which it can accommodate).

tswei, you need a bigger sub. If you're listening to music that's not really bass-heavy, and not at high volumes, it should sound all right, but I'd recommend saving up for something quite a bit more powerful. Even if your room is not that big, you may have a bigger room in the future, so a sub with power to spare is not a bad idea.

If the sub has excess power, you can turn it down. If it doesn't have enough power, you're out of luck. It's better to have more power than you need, so you have more flexibility now and in the future. Also, being patient and watching the listings while your sub-buying account builds up may allow you to score a great deal when you least expect it. Most of my speakers have been great deals with short notice.

[Quiet_Hollow]

tswei, you need a bigger sub.

[Y] +2

Take this example.

I've got a narrow-width Bill Fitzmaurice Tuba HT. At 15x36x36 and loaded with a Dayton 12", it's easily double the volume of the average large format HT sub.

Ruler flat to 15 Hz and capable of 113 dB SPL at the listening position, across it's entire pass band.

Even so, with a 14 x 18 living room in combination with the pair of La Scala at full tilt, it's just enough....as-in within a dB or two. [:|]

When the La Scala are high passed, they will take almost as much sub as you can possibly throw at them.

[CECAA850]

Tom, I thought the Table Tuba would take an 8 or 10 max (driver size). How did you shoehorn a 12 in there? I've got dual 8's in mine but it's much wider naturally.

[Quiet_Hollow]

That's because it's a Tuba HT (THT), not the Table Tuba (TT). [H]

[mark1101]

If you REALLY want it to work as best it can you need a horn sub similar to the Tuba as mentioned or even the Titan. Then, you need a separate amp and a digital speaker processor so you can adjust the gains, EQ, and delay the subs properly. These are long horns compared to the lascala. You should have 2 and run them in stereo, one with each lascala.

I personally favor the Titan as it is for music where as the Tuba is more for HT...........as recommended by Bill Fitzmaurice.

My Titans worked fantastic with my MCM Grand setup. Fantastic. I'm sure they would sound excellent with any Heritage horn bass system.

That would be doing it right!! []

Edit: I made a mistake. You would delay the lascalas, not the subs. Preamp output into the processor, outputs from processor to separate amps for lascalas and subs (2 stereo amps required). The processor would be set for a delay on the the lascalas, and be used to balance gains and EQ of each channel. Although using the amp gain controls is always best. That setup would kick butt.

[CECAA850]

That's because it's a Tuba HT (THT), not the Table Tuba (TT).

[:$]