Mis-matching subwoofers

[DrWho]

Hey Roc, I know I'm young but allow me to share some experience I've

gleaned over the years (mostly from watching others). Don't worry about the slight price change

that is coming up. There's always the next best deal happening all the

time, which are just crazy marketing ploys to push product. It's

obviously working well in this case because you're rushing to decide if

you need a second sub. Give it a few weeks, maybe months and the price

will be back to normal, if not lower. In the

meantime, you can use this time to work on getting the most out of your

original investment.

But yes, I feel pretty confident that a little bit of acoustical

treatment will completely knock your socks off. The deadness you

describe about your room is something that is more associated with the

higher frequencies. The bass notes are so huge that they don't see much

of the stuff in your room which is why most rooms dominate the bass

response. The fact that you've got crazy muddy bass in the corners is a

strong indication that your sub is in fact putting out killer volume.

Now it's just a matter of getting rid of the reflections in the room

that are causing the phase cancellation at the listening

position.

Yes, adding another sub will increase the output at the listening

position - but it's only going to be 6dB at best. Since you're already

driving the crap out of the system, I don't think that's going to be

enough. The only way it will be enough is if you can find a location

for the second subwoofer such that the modal response compliments that

of the other sub. Running some quick numbers on your room dimensions,

you've got some compounded standing waves in the 50Hz and 70Hz

regions...which musically are rather important (the impact and boom of

the kick drum). The predictions go to crap though when your room isn't

a perfect rectangle. That's where measurements come into play.

If you've got a laptop, you can put together your own measurement rig

for around $200. If you don't, there are usually companies that could

loan you equipment or even do the measurements for you. Or we could

arrange to have you rent my measurement rig. I figure about $50 +

shipping is a pretty fair price? The point is there are options.

[Roc Rinaldi]

Mike, I am right on the precipice of buying that second sub but I am going to follow your advice and not order it.

Yes, I have a laptop available. Is the $50 to rent your software or did that include the PC also? In any event, I would like to rent your measurement tools, place them on my laptop and take the measurements. What is the next step in doing this? Do I need microphone capability on my PC?

I assume that the results of the measurements will lead me to decide which frequencies either need to be boosted or dampened. This would then lead me to decide to acquire specific sound treatments for specific frequencies to be placed in specific locations in my room. Correct? Please advise.

Also, what is your opinion of including the Velodyne sub in my system as well as the f-113? Can these two subs work in harmony and complement each other or do you feel strongly that I would need to acquire another f-113 because it is identical to my other f-113? I have added the Velodyne to see what happens. It definitely non-localized the bass sound which is one of my goals. It added bass volume, but not as much as I would have thought it should.

So I believe it is important to me to have a second sub because I have three goals:

1. Non-localize the bass sound by putting a sub next to each of my main speakers

2. Level out all of the bass frequencies

3. Obtain more bass volume

If the Velodyne is OK, should I activate it also when I take my measurements?

[Roc Rinaldi]

Hey Roc, I know I'm young.......

Don't let others who have made comments about your young age throw you.

It is not how young you are that matters. It is what you know and how sincere you are about helping others that matters.

Age is a relative thing, so carry on.........

[DrWho]

Ya know, a second sub isn't a bad thing. If you think you want a second sub in the long term, then there's no reason not to do that. I was just saying that a second sub solely for the sake of fixing your current problem is not the best solution. For what it's worth, I have stereo subs at home and argue their importance in terms of other psychoacoustical effects. How's that for twisting up your decision? lol. It's just that you're talking minor nuances when you go to stereo subs and your problem is something a bit larger than a minor nuance...

Btw, the measurement rig includes the entire computer. You just open the suitcase, plug everything in and hit go and it's all precalibrated for you. You can then email me your impulse responses and I can help you interpret them over the internet and suggest a few other measurements to make sure what you're reading is accurately showing you the problems. I'm going to Indy for about a week (I leave tonight) and will be using my rig quite extensively (Roger and Colter have a ton of speakers.....), but when I get back it should be available.

[Roc Rinaldi]

Let's do it as you described.

I assume that the results of the measurements will lead me to decide which frequencies either need to be boosted or dampened. This would then lead me to decide to acquire specific sound treatments for specific frequencies to be placed in specific locations in my room. Correct? Please advise.

Also, what is your opinion of including the Velodyne sub in my system as well as the f-113? Can these two subs work in harmony and complement each other or do you feel strongly that I would need to acquire another f-113 because it is identical to my other f-113? I have added the Velodyne to see what happens. It definitely non-localized the bass sound which is one of my goals. It added bass volume, but not as much as I would have thought it should.

So I believe it is important to me to have a second sub because I have three goals:

1. Non-localize the bass sound by putting a sub next to each of my main speakers

2. Level out all of the bass frequencies

3. Obtain more bass volume

If the Velodyne is OK, should I activate it also when I take my measurements? Please advise. I assume that if I use both subs that the room optimization program with the f-113 cannot be used because the other sub is different. .

[TheEAR]

Hey Roc, I know I'm young.......

Looking avatar it is quite obvious.

So Rocky Balboa how is your Fathom doing? I would like to live close by drop in and set this for you,placement of both the sub and sitting position are paramount to sound quality and bass .Rooms can sometimes work against us.

[Roc Rinaldi]

Hey Roc, I know I'm young.......

Looking avatar it is quite obvious.

So Rocky Balboa how is your Fathom doing? I would like to live close by drop in and set this for you,placement of both the sub and sitting position are paramount to sound quality and bass .Rooms can sometimes work against us.

Arthur I agree with what you are saying. However, my room is kinda unique and I really only have one place for my seating and it really can't move around the room at all. My equipment also cannot move at all due to the room layout. My room is in a basement and it has that "pole" in the middle. If I try to move the seats then the pole gets in the way. There is also a wet bar, 30 gallon fish aquarium, 8' sliding glass door and a two sided fireplace in the room which really really limits my options for both seating and speaker placement. It is a family room that also serves as a music room. Check it out: http://forums.klipsch.com/forums/thread/885654.aspx

Arthur, it was so kind of you to suggest that you could drop by and help my room out. I would like that too. If there is any way that you can get to Baltimore, I would like to do what you have suggested.

My Fathom f-113 is doing OK. I have added back into the system my old Velodyne CT-120 sub, so I now have two subs in place. It is now somewhat boomy but I have eliminated the localization of the bass sound and I have increased the bass volume somewhat but not as much as I would have like for it to increase. However, I think the two subs working together have introduced more frequency problems, additional nulls and some overemphasized frequencies.

Checking back a few posts in this thread you will see that Dr.Who convinced me to delay any purchase of an additional f-113 for now. I think ultimately I will be getting a second f-113 but first I want to address the room treatments to get the current sound better. BTW, if I do the proper room treatments, then buy a second f-113 sub, will my room treatments be wasted and will I have to start the room treatment process over again due to adding the second f-113? Please advise.

Over my years on this earth, I have been given many unsolicited nicknames including: "Rock 'n Roll"; "Roc Man"; "Rock of Ages"; "The Rocket"; "Mr. Roc"; "Rocky"; "Roc On"; "The Rockster"; and my favorite "The Roc Meister". Your reference to Rocky Balboa was cute. I think it means that you like me.

[Roc Rinaldi]

I am absolutely convinced that you've got some serious bass nodes going on. The annoying thing is that turning up the sub just increases the magnitude of the reflections, which in turn prevents any increase in output at the listening position. With your second lessor sub hooked up in a different position, it is going to have a different modal distribution than your F-113, which means it's probably filling in a few of the 113's gaps. The fact that you can't tell much of a quality difference between the two subs just further verifies that you're not hearing much of the direct sound of the F113 - rather, you're hearing the upper harmonics of distortion that aren't being masked by the modes of the room and your ear is filling in that it thinks it's hearing the lower notes when really it is not.

Try putting your F-113 where the Velodyne is currently located, turn off the Velodyne, and report back your results.

Also, can we get some dimensions of your room? The more accurate, the better.

I think we really need to get you a measurement rig and have you run a few sweeps to locate the problem frequencies and then install a few helmholtz resonators. I'll leave it up to you to make everything look cool.

I wouldn't doubt that a hundred dollars of acoustical treatment would yield more than double the performance of purchasing a second sub...that's quite a claim and a huge bargain if it turns out to be true... []

Mike Benz I am waiting to hear from you about borrowing your measurement equipment.

[Roc Rinaldi]

Mike, got your email, will call you soon.

[DrWho]

I actually sent you a private message (so if you tried to reply to the email notification I won't be able to see it). I guess you'll be calling me at 9pm CST then?

[Roc Rinaldi]

I actually sent you a private message (so if you tried to reply to the email notification I won't be able to see it). I guess you'll be calling me at 9pm CST then?

That's 10:00 PM my time.

It may be a few days and it may be on a weekend.

I guess you know that Monday I took delivery of my second f-113. I guess that I am a bit of an impatient person. (not the worse of my faults)

I'm hoping that the risk is pretty low that adding a second sub will hurt my efforts. BTW, I already sold my old Velodyne sub, so I only have the two JL Audio f-113s.

I'll call you soon.