DIY sub for Klipschorn based HT (and music) - Tuba HT - build done (except for finish)!

[psg]

Thanks.

What do you guys use to see the frequency spectrum of a music CD?

Sting's "A thousand years" (first track on Brand New Day CD) begins with low frequency and I wonder how low it goes (and whether some of it should be filtered out).

[ClaudeJ1]

Besides a pipe organ or a contrabassoon, there are no natural instuments that go below 31 Hz. But synth bass (like Taurus bass pedals by Geddy Lee of Ruch), suharmonic synthesizers and God knows what else can produce bass down to 4 Hz. which is part of a CD specification.

A system that is ruler flat to 30 Hz. is still very powerful.

[Vicoaster]

Besides a pipe organ or a contrabassoon, there are no natural instuments that go below 31 Hz. But synth bass (like Taurus bass pedals by Geddy Lee of Ruch), suharmonic synthesizers and God knows what else can produce bass down to 4 Hz. which is part of a CD specification.

A system that is ruler flat to 30 Hz. is still very powerful.

You know, you state something that we all (at least me) tend to forget, that it is the modern age of music and cinema that had brought ultra low bass, before that 20-30 Hz was considered quite low frequency... now we want it down to 10 Hz or lower!

[CECAA850]

Besides a pipe organ or a contrabassoon, there are no natural instuments that go below 31 Hz. But synth bass (like Taurus bass pedals by Geddy Lee of Ruch), suharmonic synthesizers and God knows what else can produce bass down to 4 Hz. which is part of a CD specification.

A system that is ruler flat to 30 Hz. is still very powerful.

You know, you state something that we all (at least me) tend to forget, that it is the modern age of music and cinema that had brought ultra low bass, before that 20-30 Hz was considered quite low frequency... now we want it down to 10 Hz or lower!

Correct me if I'm wrong, but the OP is going to be using this for HT. The LFE channel on many movie sound tracks has a ton of infrasonics on them. 10 Hz content is common. I've seen waterfall charts (AVS forum I believe) that have scenes from movies with sub 20Hz content. The list is amazingly long. 30 Hz is great for music but a sub that can reproduce virtually anything on a movies LFE track is a whole different beast.

[Vicoaster]

Besides a pipe organ or a contrabassoon, there are no natural instuments that go below 31 Hz. But synth bass (like Taurus bass pedals by Geddy Lee of Ruch), suharmonic synthesizers and God knows what else can produce bass down to 4 Hz. which is part of a CD specification.

A system that is ruler flat to 30 Hz. is still very powerful.

You know, you state something that we all (at least me) tend to forget, that it is the modern age of music and cinema that had brought ultra low bass, before that 20-30 Hz was considered quite low frequency... now we want it down to 10 Hz or lower!

Correct me if I'm wrong, but the OP is going to be using this for HT. The LFE channel on many movie sound tracks has a ton of infrasonics on them. 10 Hz content is common. I've seen waterfall charts (AVS forum I believe) that have scenes from movies with sub 20Hz content. The list is amazingly long. 30 Hz is great for music but a sub that can reproduce virtually anything on a movies LFE track is a whole different beast.

I believe that you are correct, Peter does have this in his HT but uses it for some music as well...

As for the range that at HT sub needs to reach, no argumants there either, and I think you alluded to the fact that this brings a whole other set of challanges to the mix, not only from a physics standpoint but financial as well! []

[CECAA850]

Al, you are correct. As far as I'm concerned, ALL subwoofers are a type of compromise, one way or the other. I currently own an IB sub, ported sub(s), a sealed sub and a horn loaded sub. They all have their strengths and weakness. There's no "One Sub to Rule Them All" as far as I'm concerned. Certain subs lend themselves to work better in certain applications however.

[ClaudeJ1]

Correct me if I'm wrong, but the OP is going to be using this for HT. The LFE channel on many movie sound tracks has a ton of infrasonics on them. 10 Hz content is common. I've seen waterfall charts (AVS forum I believe) that have scenes from movies with sub 20Hz content. The list is amazingly long. 30 Hz is great for music but a sub that can reproduce virtually anything on a movies LFE track is a whole different beast.

Both of us are correct on this. Peter's question was of CD specifically, which is music related, not movies, whereas LFE is from DVD/Blue Ray only. But good point nonetheless.

I am currently "between subwoofers" and only using 5.0. I'm amazed at how good movies sound with my MWMs woofers, which I'm sure my receiver feeds the LFE channel to them, since they are set to "Full range" in the setup by Audyssey. They don't measure much below 40 Hz, but the impact is still there. I just don't have stuff vibrating all over the room and upstairs anymore.

Back in the days of LP, it was common to have 30 Hz. lowpass filters to save woofers in bass reflex speakers. There was no load or sound at the subsonic frequencies, and no music.........just record warp from bad commercial vinyl.

With digital, the Subwoofer based systems have become very popular, but a TRUE subwoofer should be from 10-40 Hz, eh?

[psg]

I am currently "between subwoofers" and only using 5.0. I'm amazed at how good movies sound with my MWMs woofers, which I'm sure my receiver feeds the LFE channel to them, since they are set to "Full range" in the setup by Audyssey.

I don't think you are getting full LFE then, but likely a reduced version. Since LFE runs 10 dB hotter than the main channels, mixing it in completely would clip the digital signal. There's isn't enough headroom left.

[Guest Anonymous]

PSG, killer thread, Convinced me, just bought my plans(Merry Christams to me) and cant wait for them. What exactly did you use for glue? And this sub isnt powered right?

My new grill cloth and caps came today from Bob Crites for my La Scala's.

[CECAA850]

I am currently "between subwoofers" and only using 5.0. I'm amazed at how good movies sound with my MWMs woofers, which I'm sure my receiver feeds the LFE channel to them, since they are set to "Full range" in the setup by Audyssey.

I don't think you are getting full LFE then, but likely a reduced version. Since LFE runs 10 dB hotter than the main channels, mixing it in completely would clip the digital signal. There's isn't enough headroom left.

I'm with psg on this also. Unless your receiver works differently than most (it may, I don't know) the dedicated LFE track may not be going to your mains, full range sound, yes, but LFE channel, I'm not so sure. The LFE track contains info that's not on the other channels. Your receiver would have to blend the LFE with the other tracks, which I'm not sure is possible. I'd need to read your receivers manual to know for sure.

[psg]

PSG, killer thread, Convinced me, just bought my plans(Merry Christams to me) and cant wait for them. What exactly did you use for glue? And this sub isnt powered right?

My new grill cloth and caps came today from Bob Crites for my La Scala's.

The glue is Lepage Premium PL (construction adhesive). Wear disposable gloves!

The sub is not powered. You will need an amp, but it doesn't have to be a kilowatt amp.

The family watched "Step Up 3" last night and this sub is perfect for hip hop. With 30 to 50 Watts peaks, my bowels were getting strangely vibrated! We havenever hadlow bass this good!

[ClaudeJ1]

I am currently "between subwoofers" and only using 5.0. I'm amazed at how good movies sound with my MWMs woofers, which I'm sure my receiver feeds the LFE channel to them, since they are set to "Full range" in the setup by Audyssey.

I don't think you are getting full LFE then, but likely a reduced version. Since LFE runs 10 dB hotter than the main channels, mixing it in completely would clip the digital signal. There's isn't enough headroom left.

I'm with psg on this also. Unless your receiver works differently than most (it may, I don't know) the dedicated LFE track may not be going to your mains, full range sound, yes, but LFE channel, I'm not so sure. The LFE track contains info that's not on the other channels. Your receiver would have to blend the LFE with the other tracks, which I'm not sure is possible. I'd need to read your receivers manual to know for sure.

There's never enough specific information in manuals, unfortunately. So, it's possible that I'm not getting the full LFE, but on Transformers, my MWMs sure shake the room. As to the "digital headroom" spoken here, I have 109 db efficiency and I don't crank it, so it's about 100 milliwatts to one Watt when things get loud. Also, the setup if Bi Amped. only the horns above 200 hz. get the receiver power which is 100W/ch.

I know I still have double Khorn bins as sub channels with 500W of power, but I never turn them on, since I live in a condo. Those don't go that low and add little impact. jWhen I get my tapped horn sub done, it will only come on when my neighbors aren't home.

[psg]

I am currently "between subwoofers" and only using 5.0. I'm amazed at how good movies sound with my MWMs woofers, which I'm sure my receiver feeds the LFE channel to them, since they are set to "Full range" in the setup by Audyssey.

I don't think you are getting full LFE then, but likely a reduced version. Since LFE runs 10 dB hotter than the main channels, mixing it in completely would clip the digital signal. There's isn't enough headroom left.

I'm with psg on this also. Unless your receiver works differently than most (it may, I don't know) the dedicated LFE track may not be going to your mains, full range sound, yes, but LFE channel, I'm not so sure. The LFE track contains info that's not on the other channels. Your receiver would have to blend the LFE with the other tracks, which I'm not sure is possible. I'd need to read your receivers manual to know for sure.

There's never enough specific information in manuals, unfortunately. So, it's possible that I'm not getting the full LFE, but on Transformers, my MWMs sure shake the room. As to the "digital headroom" spoken here, I have 109 db efficiency and I don't crank it, so it's about 100 milliwatts to one Watt when things get loud. Also, the setup if Bi Amped. only the horns above 200 hz. get the receiver power which is 100W/ch.

I know I still have double Khorn bins as sub channels with 500W of power, but I never turn them on, since I live in a condo. Those don't go that low and add little impact. jWhen I get my tapped horn sub done, it will only come on when my neighbors aren't home.

The headroom we speak of is not your volume dial headroom, it's for digital-to-analog conversion. If example, If a full-volume digital signal gets converted to a 2 Volt analog signal, then mixing in a 10 dB stronger LFE signal would result in a too-high (> 2V) voltage signal. The solution would be that if you tell your receiver that you don't have a sub, it drops the L+R signal by 10 dB to accomdate this possibility. But do a test and disable/enable a sub in your setup, and the gain structure isn't changed by 10 dB. They don't seem to bother to do this correctly.

In any case, for 99.9% of the population, the main speakers couldn't handle a full LFE feed. So they don't implement it.

[Guest Anonymous]

psg, i've been researching my tuba and have a few questions. did you use 1/2 inch, or 5/8? did you use Baltic birch? if so where did you get it?

[psg]

Four 5'x5' sheets of 1/2" baltic birch for $23 a sheet (or so) from a local hardware store. Really nice stuff. I bought 3 or 4 more sheets to build a custom AV rack.

[psg]

I guess I never really gave my final verdict...

It's an incredible distorsion-free sounding sub; just great sound
without any mechanical or port blowing noise. It's very easy for me
to blend it into the system for 2-channel movies, and gives drums a
very live and realistic-sounding kick-in-the-chest. Provides good
room-shacking LFE with 70W peaks in my room. Others seem to manage 3 to
5 dB more sensitivity than I do, so my room isn't great, but I still
get all the SPL I need from it. No regrets at all, but I'm still
curious about tapped horn designs. If I had to do it over, maybe I'd
build the long version (LP) instead for easier concealment, although I
have a nice otherwise-unused spot in the room for mine. Don't
underestimate its size that is even bigger 18 inchesfrom a wall.

In the past i mentionned something about feeding it a 1000W peak... It was probably 100.0W that time. I have fed it into the hundreds on rare occasions. Movies with good LFE tracks that don't go crazy low (like the second Matrix movies which I re-watched last weekend) usually end up asking for 30W peaks in my room.

I don't trust my Radio Shack meter for calibration at low frequency and plan to buy a better mic and mixer (preamp), and then will do some EQ and HP with a miniDSP.

[Vicoaster]

Thanks for the feedback Peter, I is great to know how you feel the project turned out.

Wise words about the low profile version, I have already bought the plans for the regular THT but placement and concealment have me considering the purchase of the LP plans, I could just lay a pair down under the screen the the LP version.

The idea of a tapped horn still intrigues me, wished I had seen the DIY DTS-10 kit offered early last , still expensive as compared to the THT buy much better then the full retail cost. And although I have seen some plans for TH's none seem as well documented as the Tuba which kind leaves me wondering about the end result. It is tough enough to find the time to build a verified/tested design but to go for the unknown I just don't have the luxury of that much free time!

[psg]

Yeah, having complete plans and ample ressources here was a plus in favour of the THT. I should have bought the DTS-10 kit when it was available but a finsihed version for $4000 is way out of my subwoofer budget, especially when you consider people bought them in pairs!

[Pete H]

Yeah, having complete plans and ample ressources here was a plus in favour of the THT. I should have bought the DTS-10 kit when it was available but a finsihed version for $4000 is way out of my subwoofer budget, especially when you consider people bought them in pairs!

It's all relative, there's always something better or you think is better out there, but I would bet that you have the best sub and HT setup versus anyone that you know and actually have gone to there home and listened to their system. It is hard to believe that considering the people that purchased the DTS 10 kit, not one of them produced a set of plans from the pieces and parts. BTW, this is a great build thread with alot of information on the THT and other sub concepts. Enjoy what you've made and I'm sure there will be more builds in the future.

[tragusa3]

Peter, don't sweat it that you didn't get the Danley. I've heard LaScalas with a pair of DTS10's and Khorns with a pair of the big Tubas. There are "differences", but you couldn't necessarily crown one over the other. Any advantage in SPL is lost in headroom, and to my ear, the extra extension rarely presents itself. You've got a killer system!