Dayton ultimax 15 sealed eq for lower response?

[yepimonfire]

I'm considering building the Dayton ultimax 15 sealed sub using the PE kit. From what I've read, it will start rolling off at about 35hz, what I want to know is whether or not I could apply parametric eq to get it down to 20hz. I'm aware this will require more power for the lowest frequencies, however, based on the sensitivity and SPL requirements, I don't think that it should be a problem, I don't really want to build a ported box for two reasons, I don't have the time to do that, and I'd like the shallower rolloff.

Would this work or would I run into problems?

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[everettT]

Yes it can. However I'd look at doing this function with mini dsp.

https://www.minidsp.com/applications/advanced-tools/linkwitz-transform

 

[rojo]

I do the same thing with my sealed CSS SDX12 using a miniDSP.

Close-mic native response:

In-room response shaped by miniDSP:

But honestly, a flat response to mid 20's is good enough. If I knew when I built this sub what I know now, I would've gone ported. Have a look at shadyJ's Subwoofer Candy thread, and you'll see many real-world examples representative of typical sub bass content, which usually doesn't go as low as one might think. Because of this shaping, even with an xmax of 28mm, I still bottom out on the treachery 30 seconds into "Edge of Tomorrow" if I'm not careful with the volume. Really, a flat response into the teens is rarely useful for more than bragging rights.

 

[yepimonfire]

I do the same thing with my sealed CSS SDX12 using a miniDSP.

Close-mic native response:

In-room response shaped by miniDSP:

But honestly, a flat response to mid 20's is good enough. If I knew when I built this sub what I know now, I would've gone ported. Have a look at shadyJ's Subwoofer Candy thread, and you'll see many real-world examples representative of typical sub bass content, which usually doesn't go as low as one might think. Because of this shaping, even with an xmax of 28mm, I still bottom out on the treachery 30 seconds into "Edge of Tomorrow" if I'm not careful with the volume. Really, a flat response into the teens is rarely useful for more than bragging rights.

Yes I know that. Outside of 32' stops in organ music, there isn't a lot of content below 30hz in a majority of music. Most of LFE tracks I've run a spectral analysis on have most of their content between 25hz and 50hz, outside of a few rare movies that have infrasonic subharmonics on some scenes.

Why would you chose a ported design over a sealed? I'm not sure how the impedance or driver excursion behaves on a sealed sub below the -3dB point, I know on a ported sub the port behaves like a hole in the box below the tuning frequency, and the woofer acts as if it's in free air, I also know that sealed subs generally have a faster decay time and therefore are less likely to exacerbate room modes, which is another reason I'm considering sealed. If the sub could handle 1600w for those brief peaks (its rated 800w continuous, 1600 program and theoretically should handle very brief peaks of 3200w) that would give me 109dB in room at 9' (which is how far I sit). Assuming 20hz is 6dB down that's 103dB at 20hz. Currently with the dayton sub 1500 I'm using I get a maximum of 105dB from 25hz on up (power limited, not excursion). I'm really trying to avoid having to build a box from scratch. I'd like to be able to achieve 110dB at the MLP, since I usually prefer watching movies at -5dB, right now I'm limited to -10dB and every once in awhile even at this level specific scenes will introduce hard clipping that sounds as if the sub is knocking. Ideally I want to at least reach 25hz, with a useful output at 20hz. My only two options is diy, or add another sub 1500 due to budget constraints, between working a ton and home life, I don't have the time to build the box myself.

 

[j_garcia]

Sub that is good to lower than 20Hz is great, but with most sealed subs that output is "clean" and does not really give you that pant leg flapping rumble that low. Yes it is there and can be measured but it isn't as obvious to the ear as a low tuned vented sub. Good output to ~25 and clean to 20 is good in my book. My sealed drops off quick in the teens and does very well in the 30Hz+ range and I have never felt I needed more even in a very large room. That's coming from a 17Hz tuned vented sub too.

 

[ski2xblack]

The room will play into which approach will meet your goals, too. Sealed may realize deeper extension when cabin gain comes into play, even without eq. But if super loud and super deep are the goals...

 

[TLS Guy]

I really have trouble understanding the popularity of those Dayton Ultimax drivers. There is not much max about them.

My objections are that they do not model all that well. They are high Q drivers, and so the bass will not be as tight. This driver is 0.47. I think this is to allow for a relatively low F3 without Eq.

Talking of Eq the xmax is only 19 mm. At full rated power there is no room for Eq.

The F3 in a 2.75 cu. ft. sealed box is 32 Hz. Roll off starts at around 50 Hz. The max power the driver will take at 25 Hz is 100 watts. This gives an spl. of just over 100 db

The total Q is 0.71 and so will be on the warm side of just acceptable.

Max impedance is 15 ohms at 35 Hz, otherwise impedance is 4 ohms above and below tuning to 500 Hz.

Sealed subs only advantage is small size. Otherwise it is all downsides. A loudspeaker cone is a dreadful coupler to the room. In order to get low Q, then roll off is way above Fs. Then you end up with huge expensive motor systems and huge amps. That is not the approach I favor unless space is at an absolute premium.

The bottom line is that when you see that sub is 800 watts, it is totally deceptive, as in the lower sub ranges it is actually quite a low powered sub. So yes it will take 800 watts RMS, but only above 40 Hz.

 

[yepimonfire]

I really have trouble understanding the popularity of those Dayton Ultimax drivers. There is not much max about them.

My objections are that they do not model all that well. They are high Q drivers, and so the bass will not be as tight. This driver is 0.47. I think this is to allow for a relatively low F3 without Eq.

Talking of Eq the xmax is only 19 mm. At full rated power there is no room for Eq.

The F3 in a 2.75 cu. ft. sealed box is 32 Hz. Roll off starts at around 50 Hz. The max power the driver will take at 25 Hz is 100 watts. This gives an spl. of just over 100 db

The total Q is 0.71 and so will be on the warm side of just acceptable.

Max impedance is 15 ohms at 35 Hz, otherwise impedance is 4 ohms above and below tuning to 500 Hz.

Sealed subs only advantage is small size. Otherwise it is all downsides. A loudspeaker cone is a dreadful coupler to the room. In order to get low Q, then roll off is way above Fs. Then you end up with huge expensive motor systems and huge amps. That is not the approach I favor unless space is at an absolute premium.

The bottom line is that when you see that sub is 800 watts, it is totally deceptive, as in the lower sub ranges it is actually quite a low powered sub. So yes it will take 800 watts RMS, but only above 40 Hz.

What would you suggest then?

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[TLS Guy]

What would you suggest then?

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That depends on your requirements, expectations and budget.

A powerful sealed sub is an expensive option and complex. A ported sub will deliver much greater low end output per dollar.

 

[everettT]

That's why I referenced the linkwitz formula. The ultimax driver that Mark Seaton uses (18") gets unbelievable extension with his "eq" applied and can handle a ton of power. The driver can be manipulated well. Parts express had been out of stock on the 18 because of his buys. I agree with you 99.9% of the time but this driver has wiggle room. The mid bass isn't as good as the RS version (slightly) but the low extension can be sick. Here is Josh's take on the 18

http://www.data-bass.com/data?page=system&id=116

I really have trouble understanding the popularity of those Dayton Ultimax drivers. There is not much max about them.

My objections are that they do not model all that well. They are high Q drivers, and so the bass will not be as tight. This driver is 0.47. I think this is to allow for a relatively low F3 without Eq.

Talking of Eq the xmax is only 19 mm. At full rated power there is no room for Eq.

The F3 in a 2.75 cu. ft. sealed box is 32 Hz. Roll off starts at around 50 Hz. The max power the driver will take at 25 Hz is 100 watts. This gives an spl. of just over 100 db

The total Q is 0.71 and so will be on the warm side of just acceptable.

Max impedance is 15 ohms at 35 Hz, otherwise impedance is 4 ohms above and below tuning to 500 Hz.

Sealed subs only advantage is small size. Otherwise it is all downsides. A loudspeaker cone is a dreadful coupler to the room. In order to get low Q, then roll off is way above Fs. Then you end up with huge expensive motor systems and huge amps. That is not the approach I favor unless space is at an absolute premium.

The bottom line is that when you see that sub is 800 watts, it is totally deceptive, as in the lower sub ranges it is actually quite a low powered sub. So yes it will take 800 watts RMS, but only above 40 Hz.

 

[TLS Guy]

That's why I referenced the linkwitz formula. The ultimax driver that Mark Seaton uses (18") gets unbelievable extension with his "eq" applied and can handle a ton of power. The driver can be manipulated well. Parts express had been out of stock on the 18 because of his buys. I agree with you 99.9% of the time but this driver has wiggle room. The mid bass isn't as good as the RS version (slightly) but the low extension can be sick. Here is Josh's take on the 18

http://www.data-bass.com/data?page=system&id=116

Well that driver is a bit more promising.

x-max is 22 mm and with the larger cone it can handle 200 watts at 25 Hz, and produce 115 db.

However my objection that the driver has a Qt of 0.53 stands. That is really creeping up on acoustic suspension category.

I would personally not use that driver. I really dislike the quality of bass from high Qt drivers. I'm fanatical about a tight and realistic bass with no ringing or carry over.

The cheaper 18" Dayton driver I designed the ported sub for, makes are far better sub. A number of members have built these subs and have been thrilled with them.

 

[shadyJ]

Well that driver is a bit more promising.

x-max is 22 mm and with the larger cone it can handle 200 watts at 25 Hz, and produce 115 db.

However my objection that the driver has a Qt of 0.53 stands. That is really creeping up on acoustic suspension category.

I would personally not use that driver. I really dislike the quality of bass from high Qt drivers. I'm fanatical about a tight and realistic bass with no ringing or carry over.

The cheaper 18" Dayton driver I designed the ported sub for, makes are far better sub. A number of members have built these subs and have been thrilled with them.

Look at the group delay, not much ringing at all there. This driver looks solid to me, especially for the price.

As for Qts, Josh measured 0.422, and Josh also measured much less moving mass weight than Dayton's specs. But we hear frequency response, not Qts, so this shouldn't be concerning. The response shape is not very peakish really.

Von Schweikert uses the Ultimax drivers in his $300k Ultra 11 speakers. Not saying that price tags necessarily makes these drivers good or those speakers good, it just an amusing factoid.

 

[TLS Guy]

Look at the group delay, not much ringing at all there. This driver looks solid to me, especially for the price.

As for Qts, Josh measured 0.422, and Josh also measured much less moving mass weight than Dayton's specs. But we hear frequency response, not Qts, so this shouldn't be concerning. The response shape is not very peakish really.

Von Schweikert uses the Ultimax drivers in his $300k Ultra 11 speakers. Not saying that price tags necessarily makes these drivers good or those speakers good, it just an amusing factoid.

If the Qts is 0.422, that is a 20% reduction which is highly significant and result in less cone excursion and higher output, as the suspension must be stiffer than stated.

So estimating Qtc would go down to around 0.6 and power handling likely double in the 25 Hz region. So with a 12 db per octave boost starting at 50 Hz and a second order high pass filter at 20 Hz, then it probably would be a formidable sub.

I would suggest anyone wanting to do a build, measure the T/S parameters of their driver before cutting wood.

 

[everettT]

Again that's why I referenced the linkwitz transform , after manipulation the total qts is Reshaped. Give the drivers a chance due to their high performance to cost ratio. Linkwitz is a hell if engineer and if he get above average results and Mark gets the same without revealing his methods, as you mentioned it will take work , but it can be rewarding

Well that driver is a bit more promising.

x-max is 22 mm and with the larger cone it can handle 200 watts at 25 Hz, and produce 115 db.

However my objection that the driver has a Qt of 0.53 stands. That is really creeping up on acoustic suspension category.

I would personally not use that driver. I really dislike the quality of bass from high Qt drivers. I'm fanatical about a tight and realistic bass with no ringing or carry over.

The cheaper 18" Dayton driver I designed the ported sub for, makes are far better sub. A number of members have built these subs and have been thrilled with them.

 

[yepimonfire]

That depends on your requirements, expectations and budget.

A powerful sealed sub is an expensive option and complex. A ported sub will deliver much greater low end output per dollar.

I'd like to get 115dB down to 20hz, some q is okay, just not super high. Frankly, I don't give a damn how big or ugly the cabinet is. I'd like to stay below $400 not including amplification.

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[everettT]

I'd like to get 115dB down to 20hz, some q is okay, just not super high. Frankly, I don't give a damn how big or ugly the cabinet is. I'd like to stay below $400 not including amplification.

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You want 115db @ 20hz continuous? And below $400 Good luck

 

[TLS Guy]

f you are not worried about the cabinet size, then this sub will give you 115 db at just over 20 Hz.

F3 is 22.48 Hz. No eq required.

A number of members have built this sub and have been very pleased with it. Ares was the first to built it, and Haloeb did a wonderful build of two of them.

 

[roadrune]

http://www.avsforum.com/forum/155-diy-speakers-subs/1451519-lilmike-s-lilwrecker.html

I have two

 

[roadrune]

In case anyone was wondering what the point my last post was: this is a sub capable of 120db @ 20hz and can be built for $400.

 

[TLS Guy]

In case anyone was wondering what the point my last post was: this is a sub capable of 120db @ 20hz and can be built for $400.

Were those measurements, done outside, or are they contaminated by room modes? There is a nasty peak at 60 Hz and dip at 90 Hz. The peak is especially problematic. If that is the response it would need crossing over 24 db per octave low pass at 40 Hz.