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Discussion Starter #1
Hello and welcome!

My name is Jules, I am a Stereo-Purist, been listening to B&W 683 on a Marantz SR14 so far.
Now I am switching to active monitors, Adam A7X.

What I need now is a brilliant DIY concept for one reference-class musical subwoofer.
It must play accurate and very deep (16Hz -3dB) and the cabinet must be as compact as possible.

I have been reading a little bit on these subjects and must say, I am intrigued by today's
technology. A Rythmik Direct Servo sub would probably be my first choice, but it's far too
expensive for me.

My budget is only 400€. To make the best of it, I was thinking of a Dayton UM15-22 chassis
which starts at 15Hz and is not an obscenely huge driver. Here in Germany it costs 303€
shipping included.

The other part is the cabinet - this is where I must rely on the most experienced people here.
I tried some programs (BassCad, WinISD, etc.) and the calculated results vary quite dramatically...
Dayton recommends a 3.1 cubic feet cabinet for this chassis. Rythmik uses a 4 cubic feet cabinet for
their 15" drivers. According to the programs, the tuning of a sub to 16Hz would require a really huge
cabinet. I believe this is all misleading me...

I want an accurate 16-120Hz spectrum (-3dB) in my 4x4x2,5m room - for that I need the most reliable
cabinet parameters. Positioning, measurements and ParaEQ will follow later.


I have a little woodworking experience and most tools except a cnc-router at my disposal, so I believe
I can build the cabinet myself. I will choose plywood or massive wood for this project, however which
kind of wood that is still unclear - maybe you can help me with this decision. Beech or maybe even oak...

I hope you can help me to make the best choices for the highest sound accuracy and quality possible within
this budget.
 

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Discussion Starter #3 (Edited)
I asked Rythmik and an L12 would cost about ~850-900€ shipping included.

BTW I started burning in my ADAM A7X today, I love how real and rich they play :R


I've been looking at the SVS SB-2000 as well. I'm not sure if it will sound less accurate than a 400€ diy sealed sub.
 

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Unless you have a "perfect" spot for the sub, that if you are lucky provides accurate bass at a single locked in listening position, to produce accurate bass means at least two (and preferably four) well placed subs. The room controls the bass, not the musicality of the sub. Google "multisub", "Harman", "Welti", "room nodes", "Schroeder" etcetera for more info.

I am running two small 30 litre sealed Dayton RSS210HF-4 subs, in a room your size. Fairly budget friendly, quite flat/low distortion in room response across the entire sofa down to 17Hz, as loud as I can stand it. I am currently building two more to see if I can eek even more bass performance out of the room :T .
 

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I asked Rythmik and an L12 would cost about ~850-900€ shipping included.

BTW I started burning in my ADAM A7X today, I love how real and rich they play :R


I've been looking at the SVS SB-2000 as well. I'm not sure if it will sound less accurate than a 400€ diy sealed sub.
If a L12 is that much over your budget I would stick with the 400€ diy sealed sub.
 

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Discussion Starter #6
Unless you have a "perfect" spot for the sub, that if you are lucky provides accurate bass at a single locked in listening position, to produce accurate bass means at least two (and preferably four) well placed subs. The room controls the bass, not the musicality of the sub. Google "multisub", "Harman", "Welti", "room nodes", "Schroeder" etcetera for more info.

I am running two small 30 litre sealed Dayton RSS210HF-4 subs, in a room your size. Fairly budget friendly, quite flat/low distortion in room response across the entire sofa down to 17Hz, as loud as I can stand it. I am currently building two more to see if I can eek even more bass performance out of the room :T .
I guess the sound spectrum we perceive is manipulated up to 60-70% by the room itself.
Been living in a 4x3x3,5m room with very stiff walls for about 12 years. A basic 60€ sound system my dad is using now sounds absolutely spectacular/unbelievable in there. Very rich and extremely dynamic. When I was listening to a pair of Heco Celan XT 701 hooked on a Denon AVC-A1SE in there... the near field (1,3m distance) in that room... this is where I got my highest eargasms up to this day. My current room is the biggest contra for sound that I know of, the floor is dampened, the walls are sluggish and the geometry is 4x4x2,5m...
The only chassis that isn't affected by this room, is the X-Art AMT in my A7X' - this leaves me grinning speechless every time they play in here - it seems like they simply don't care about this room's sonic problems. I guess that's Oscar Heil for you :R


If a L12 is that much over your budget I would stick with the 400€ diy sealed sub.
That would be my primary agenda. I calculated what a DS1510 + H600PEQ3 kit would cost - 769$ +191$~ tax + 200$ shipping - that would be 1035€~ + 65€ material for a 4cuft cabinet. Well, if I sell my B&W 683's then I could order this kit.

Just tell me, is the difference in accuracy between a Rythmik E15 and a Dayton UM15-22 worth it?

Over the last few years I have conducted countless practical acoustic experiments - by putting granite below the spikes and some barbell weights on the speaker/woofer I was able to get a much more massive and timed low frequency spectrum. This especially helps me handling this room's dampened floor.
 

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Unless you have a "perfect" spot for the sub, that if you are lucky provides accurate bass at a single locked in listening position, to produce accurate bass means at least two (and preferably four) well placed subs. The room controls the bass, not the musicality of the sub. Google "multisub", "Harman", "Welti", "room nodes", "Schroeder" etcetera for more info.
Specifically, google "Schroeder frequency"
Here's one well-written article.

:bigsmile:
 

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Just tell me, is the difference in accuracy between a Rythmik E15 and a Dayton UM15-22 worth it?
No one can tell you that because that answer is personnel. You will find people that do not like Rythmik subs because they are too lean and sound weak. I have seen comments from shootout were guys had to walk to the Rythmik sub and touch the driver while music or movie was play just to see if it was on. Guys like me love that but some people don't like spending money on a sub that they can't hear.
 

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Discussion Starter #9
Specifically, google "Schroeder frequency"

:bigsmile:
Thanks for this read, the High/Midrange and Lowrange dilemma in positioning is something I had figured out the hard way a few years ago. This is why 3-way floorstanders were always a huge dilemma in my room... my A7X' make it really an easier world here, since the tweeters are completely independent - just Mid and Lows to manage without coherence - I'm so glad I bought these!

I'll get to it this weekend, whew finally some room-science!


No one can tell you that because that answer is personnel. You will find people that do not like Rythmik subs because they are too lean and sound weak. I have seen comments from shootout were guys had to walk to the Rythmik sub and touch the driver while music or movie was play just to see if it was on. Guys like me love that but some people don't like spending money on a sub that they can't hear.
Too lean and weak? Reminds me somehow of Teufel subs here in Germany... I never liked those because they sound kind of short-timed, dried out and unnatural/artificial. If a Rhytmik sub sounds similar, then it's clearly not what I prefer. I liked the bass character of B&W's 683 S1 so far, however I want a much more refined, detailed and articulate bass from my sub to be.

Looks like I should go my intuitive way, trying out some subs first.
A SVS SB-2000 should be a good start. After that I can proceed to
building one Dayton sub and only if absolutely necessary, another one later.

I love sound which gets as real and rich as possible - those instruments have to flash me! I like to listen loud as well, but never too loud since my hearing is very sensitive - for example I can't sleep unless it's completely silent, <10dB is a must, ticking clocks are a nightmare to me...

I'll try my SR14 as a preamp on the A7X this weekend, hopefully the nice warm character will finally add up.
If not, then I will most likely use the SR14 for powering the sub/subs in the future.
 

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Too lean and weak? Reminds me somehow of Teufel subs here in Germany... I never liked those because they sound kind of short-timed, dried out and unnatural/artificial. If a Rhytmik sub sounds similar, then it's clearly not what I prefer. I liked the bass character of B&W's 683 S1 so far, however I want a much more refined, detailed and articulate bass from my sub to be.
"short-timed, dried out and unnatural/artificial" The first two terms you used describes natural bass. Real bass is hard to hear and you pick up on the overtones more than the core note. We are why more use to artificial bass than real bass. If you think about it the bass we hear all the time comes from speakers more often than not. Car speakers, movies, even live shows and jazz clubs. That bass guitar or upright bass in a Jazz Club are just speakers playing. When we hear real Bass we often have to pause and think, we say to our self "what is that... do you hear that... Ohh it's a train". Rythmik is the closest thing for a good price that will give you a natural Bass. It is not for everyone.

The best way I like to put it is. If someone walks into your music room while the system is play and sees a just a couple of speakers. Do you want them to say "Wow, your system sounds good where is the sub that that Bass is awesome" or do you want them to say "Wow, your system sounds good, your speakers can really play low"

Looks like I should go my intuitive way, trying out some subs first.
A SVS SB-2000 should be a good start. After that I can proceed to
building one Dayton sub and only if absolutely necessary, another one later.

I love sound which gets as real and rich as possible - those instruments have to flash me! I like to listen loud as well, but never too loud since my hearing is very sensitive - for example I can't sleep unless it's completely silent, <10dB is a must, ticking clocks are a nightmare to me...
DIY is your best option until you know What you want.
 

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Discussion Starter #11 (Edited)
"short-timed, dried out and unnatural/artificial" The first two terms you used describes natural bass. Real bass is hard to hear and you pick up on the overtones more than the core note. We are why more use to artificial bass than real bass. If you think about it the bass we hear all the time comes from speakers more often than not. Car speakers, movies, even live shows and jazz clubs. That bass guitar or upright bass in a Jazz Club are just speakers playing. When we hear real Bass we often have to pause and think, we say to our self "what is that... do you hear that... Ohh it's a train". Rythmik is the closest thing for a good price that will give you a natural Bass. It is not for everyone.

The best way I like to put it is. If someone walks into your music room while the system is play and sees a just a couple of speakers. Do you want them to say "Wow, your system sounds good where is the sub that that Bass is awesome" or do you want them to say "Wow, your system sounds good, your speakers can really play low"


DIY is your best option until you know What you want.

Natural bass... well I have my own experiences on that :R
Nature has provided me moments of sheer awe and those have become my own reference...
A gigantic tempest thunder strike has an impact on me unlike anything else.
I insist for my future sub to be able to reproduce that impact - if it does, then it's a glorious victory for my phrenic!

On the other side I also want finesse, articulation and accuracy - but not with a dried out character - it must be juicy!


I know what I want: Both sides of that bass coin. Maybe it's time to try out a powerhouse + an artist together!

Also, what about this one?
http://www.hsuresearch.com/products/vtf-15hmk2.html

Seems like a very good choice, the price is quite good for what it delivers.

Is there a review of the Dayton UM15-22 anywhere? I'd like to see some spectrographs, just to be sure.
 

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I don't know the specifics of your room, but if you can go Infinite baffle, take a look into that. your main cost is the speaker itself since the area behind the room (should it exist of course) becomes the subwoofer 'box'. Not all rooms allow for this, but if so, something to consider I would think.
 

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Discussion Starter #13 (Edited)
I am thinking about a 360l vented concept tuned to 15Hz.

According to winisd the -3dB point should be at 15,4Hz.

I've noted that the group delay of a sealed cabinet is below 10ms at all times.
However the extension advantage of a ported concept is too huge to ignore.
So I think I will settle for port tuning afterwards, but I still need to get correct
dimensions for the port. Maybe 3x 6,1cm*27cm or one big 14cm*46cm port...
Any hints?

A cycle of 15,4Hz lasts ~64,935ms.
With a group delay of 46,1ms at 15,4Hz this should be acceptable.
Please correct me if I am wrong - this is all new to me.

Winisd suggests the following cabinet dimensions:
W 76,5 cm
H 119,8 cm
D 47,7 cm

Would it be fine to use the front baffle on a depth side?

Let me know what you think! :R
 

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I am running two small 30 litre sealed Dayton RSS210HF-4 subs, in a room your size. Fairly budget friendly, quite flat/low distortion in room response across the entire sofa down to 17Hz, as loud as I can stand it. I am currently building two more to see if I can eek even more bass performance out of the room :T .
Two sealed 8's aren't going to give you flat response as loud as you can stand it at 17 hz, and even if it did, you wouldn't be trying to double the subs. :)
 

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Just tell me, is the difference in accuracy between a Rythmik E15 and a Dayton UM15-22 worth it?
Dayton ultimaxes sound very nice on music. They are very controlled and tight. Voice coil impedance (Le) is among the lowest you'll find in its class, measured at around 1.5 mH, which is very good for what it is. Only way to improve on that much is to go with an Acoustic Elegance, most of theirs are like 0.3 mh. This keeps the impedance rise down so that midbass shines, which is what gives you the detail on bass guitar and whatnot.

However, if you're looking at a 15, I'd bump up to an 18. The box for a 15 isn't that much smaller than an 18. Just not much to lose in terms of a footprint but more performance to gain.

Realistically speaking, most any sub can be musical, especially sealed ones. The biggest issue is blending with your mains, that's where most of the detail comes from.
 

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"short-timed, dried out and unnatural/artificial" The first two terms you used describes natural bass. Real bass is hard to hear and you pick up on the overtones more than the core note. We are why more use to artificial bass than real bass. If you think about it the bass we hear all the time comes from speakers more often than not. Car speakers, movies, even live shows and jazz clubs. That bass guitar or upright bass in a Jazz Club are just speakers playing. When we hear real Bass we often have to pause and think, we say to our self "what is that... do you hear that... Ohh it's a train". Rythmik is the closest thing for a good price that will give you a natural Bass. It is not for everyone.

The best way I like to put it is. If someone walks into your music room while the system is play and sees a just a couple of speakers. Do you want them to say "Wow, your system sounds good where is the sub that that Bass is awesome" or do you want them to say "Wow, your system sounds good, your speakers can really play low"
I've read this multiple times to figure out what you're getting at, and I just don't agree at all.

What you are describing is a single sealed sub's inability to produce the lowest audible frequencies at any respectable volume. When it tries, flop as it may, it just can't do it. What will happen though, is that it will produce harmonic distortion from attempting to, which is why you are picking up on the "overtones". That's NOT how it's supposed to be, if anything this is a bad thing.

Distortion is bad. Frequency response that falls off a cliff is bad. Room modes are bad. You can't repackage this as "natural" and call it good. It's not.

To counteract this, the best thing you can do, especially with sealed subs, is get multiple subs, preferably four, and position one in the middle of each wall, or at least in the corners, and employ a DSP to counteract the frequency response slope down low, especially if you go DIY.

You get more displacement for the lowest frequencies. They aren't working as hard so you get less distortion. With this placement the room modes are smoothed out. With the EQ and enough overhead you'll get the low frequencies.

That's not to say that bass can't sound natural, its just that most people call it "accurate". Chuffing from a port, ringing from a small box, midrange artifacts coming through a port, harmonic distortion, all these can lead to unnatural sounding bass. Sealed is typically the easy way out of MOST of these problems, especially with music, but if anything its worse in the distortion / overtones department because it is less efficient than ported anywhere near the tuning frequency.

With ported you have a huge boost in efficiency at the tuning frequency, as well as back pressure from the port which keeps the cone from moving much. Sealed is the opposite, very inefficient at the same frequency, so it has to work MUCH harder and move MUCH more, which produces much more distortion, aka. overtones. This is not good in general, you should be trying to fight it rather than embrace it and call it natural.

You can't just throw a single sub in a sealed box, hook it up, and call it good. Just lots more to it than that.
 
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