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pat_in_dfw

Best 15" drivers for DBB

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I sent this message in a p.m. to a member previously because we were having a discussion but I thought it would be a good conversation topic for the entire group and hopefully I can get some Brains involved who are much smarter than me to offer their input.

 

I am going to pick up a set of DBBs this coming weekend. They don't have drivers so I need to find ones that work. Previous comments have been to use the Emminence Kappalites or the K33 Cornwall driver but I want to extend the bass and use this as a subwoofer to complement LaScala mains.  I based my model off a 6 cu ft volume and tuning of 34hz. If these values are not right please tell me.

 

I've looked at the Kappalite as well as others.  I'll list what I found.

 

Crites:  I looked at Crites Cornwall replacement woofers mainly as a price reference. I couldn't find the T/S parameters but I'll admit that I didn't look hard either.

 

Our CW1526C 15 inch Cast Frame Woofers.  Replacement for the Klipsch K-33E for Klipschorn, Belle Klipsch, and Cornwall.  Shipping is $25.00 by FedEx in the US. (Not for the LaScala).

Model CW1526C Pair:  $275.00.  

 

Our CW1526 15 inch Stamped Steel Frame Woofers.  Replacement for the Klipsch K-33E for  Klipschorn, Belle Klipsch, Cornwall and LaScala.  Shipping is $25.00 by UPS in the US.

Model CW1526 Pair:  $240.00

 

Our CW1526F has the same specs as our CW1526.  Difference is that the CW1526F has a thinner front gasket and a second gasket behind the frame.  This woofer works better for flush mounting in a motor board such as that on the Cornwall II.  It also works well for rear mounting for the Cornwall 1.  Shipping is $25.00 per pair in the US.

Model CW1526F Pair:  $260.00  

 

Based on the box volume of the Cornwall (6 cu ft) and a tuning frequency of 32hz-34hz I ran the following drivers with the results as shown:

 

Klipsch K33e (Emminence 15162) (cost ??) (300w RMS per cabinet)

SPL dB 96.6

F3 of 50hz with 34hz port tuning (not great - I can't see using the stock K33e for low frequencies)

 

Eminence Kappalite 3015LF ($199 each) (900w RMS per cabinet)

Sensitivity  96 dB

F3 of 52hz (not really that low - I couldn't see using this)

 

Emminence Lab15 ($285 each) (1200w RMS per cabinet)

Sensitivity   88.5 dB

F3 of 32hz (nice, but at that price it's almost $1200 for 4 drivers)

 

Dayton Audio DCS380-4 15" Classic Subwoofer 4 Ohm ($87 each) (500w RMS per cabinet)

Sensitivity   93.6 dB

For this I would have to lower the tuning frequency to 19hz by making the port opening smaller or adding to the length.

Final results of F3 at 30hz  

 

Goldwood GW-15PC-4 ($88 each) (550w RMS per cabinet)

Sensitivity   94.9 dB

F3 of 34hz with no adjustments to tuning frequency

 

Goldwood GW-15PC-8 ($89 each) (550w RMS per cabinet)

Sensitivity    92.3 dB

F3 of 35hz

 

Dayton Audio UM15-22 15" Ultimax DVC ($189 each) (1600w RMS per cabinet)

Sensitivity   86.5 dB

Would have to change the port tuning to 22hz by closing off some of the port opening or changing port length.

F3 of 24hz with adjusted port tuning

 

Dayton Audio RSS390HF-4 15" Reference HF Subwoofer 4 Ohm ($155 each) (1000w RMS per cabinet)

Sensitivity  91.2 dB

Would have to change the port tuning to 22hz.

F3 of 24hz with adjusted port tuning

 

Dayton Audio RSS390HO-4 15" Reference HO Subwoofer 4 Ohm ($165 each) (1600w RMS per cabinet)

Sensitivity  92.8 dB

slightly adjust tuning frequency to 29hz

F3 of 28hz with adjusted port tuning

 

MCM Audio Select (55-2953)  ($32 each) (400w RMS per cabinet)

Sensitivity (1W/M): 98 dB (very nice)

F3 of 42hz at 34hz port tuning

 

 

With all of this data I think I can toss out the idea of using the stock K33 driver because it would have a low end F3 of barely 50hz.  I don't know how the Cornwall claims a low end of 34hz unless it's -10db at 34hz.

 

Based on the price vs performance I'm leaning toward the MCM 55-2953.  It only handles 400w RMS, but with the efficiency of 98db I don't think it will need very much power to reach high levels.  I can live with an F3 of 42hz at that price.  To get what I really want I would have to use the Dayton HF sub with a change in the port tuning to get a F3 of 24hz.  But $155 per driver vs $32 per driver is quite a big difference.  

 

Given a 3bd increase every time power doubles the output for the MCM driver would be:

 

1w = 101db (two drivers coupled together gives a 3db increase)

2w = 104db

4w = 107db

8w = 110db

16w = 113db

32w = 116db

64w = 119db

128w = 121db

256w = 124db

400w = 125db or 126db

 

That means by spending $130 I could get 125db levels......not bad.

 

 

What are your thoughts?

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Watts are a thermal rating and nothing more, don't expect to pump 400 watts into a 400 watt driver unless it is properly high passed and tuned.

 

I have used most of these woofers with the exception of the Goldwoods & MCM, none of these are going to blend properly unless installed into a horn loaded design.

 

Will they work ? Yes, but don't have high expectations.

 

Do it right the first time, save time and money by building or buying a proper horn loaded unit to accompany the horn loaded mains.

 

 

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1 minute ago, pat_in_dfw said:

Yes...typo. I'll try to edit it.

You can edit the title by editing your first post.

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1 hour ago, jason str said:

Watts are a thermal rating and nothing more, don't expect to pump 400 watts into a 400 watt driver unless it is properly high passed and tuned.

 

I have used most of these woofers with the exception of the Goldwoods & MCM, none of these are going to blend properly unless installed into a horn loaded design.

 

Will they work ? Yes, but don't have high expectations.

 

Do it right the first time, save time and money by building or buying a proper horn loaded unit to accompany the horn loaded mains.

 

 

I don't know that many horn loaded designs that will give much bass extension other than the Khorn that won't take up half the room. The price on the DBBs are right (free) so I'm trying to come up with a driver to maximize the cabinet. 

 

The power ratings were RMS and meant to show a comparison between drivers.

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3 minutes ago, CECAA850 said:

You can edit the title by editing your first post.

Thanks. I didn't realize that.

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Thanks for thinking of me Carl;

 

I have four K-48 woofers, these came in Chorus IIs and Klipsch Professional Stubby Subs. Two of them are in perfect original condition, and I think the voice coils are good on the other two, but they need new cones. I also have a single K-45 that has just been reconed, but I am working on a trade right now, so I have to wait and see on how that turns out. Regardless, I won't be doing anything until after Hope is over. Thanks guys  :)

 

Roger

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I believe the DBB cabinets are already tuned, the ports are the triangled in each corner. Use them for what they were designed.

 

Bruce

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I have a pair of DBBs and use the Crites cast frames because that's what came in them and I know they work well in that application from past experience.

 

It's interesting that you looked at all those different woofers and then selected the absolute cheapest.  What is your audio goal?  Do you think the cheapest by far will sound anywhere near the better ones?

 

Not trying to be a jerk but you made that very involved post then picked the $32 woofer.  Why bother?  :D

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Best bang for the buck to match with your mains would be a double 8" Table Tuba long style, takes up a 15 x 20" (more or less) footprint and 5 ft height.

 

2 x 8" woofers = $70 >Link<

 

200 watt amplifier

 

Add a few sheets of plywood, glue and hardware and you are still under $300

 

Even if you have little carpentry skills one can be built following the easy to follow plans or if you are all thumbs for a minimal investment you can have one built.

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1 hour ago, mark1101 said:

I have a pair of DBBs and use the Crites cast frames because that's what came in them and I know they work well in that application from past experience.

 

It's interesting that you looked at all those different woofers and then selected the absolute cheapest.  What is your audio goal?  Do you think the cheapest by far will sound anywhere near the better ones?

 

Not trying to be a jerk but you made that very involved post then picked the $32 woofer.  Why bother?  :D

It wasn't the fact that it was the cheapest.  I don't have unlimited funds so I was looking at the best performance/price ratio.  I looked at the best performance that I could get regardless of cost without changing the port tuning and that came from the Lab15 at a cost of $285 per driver ($1140).  That gave a response down to 32hz with a slight boost at 40hz that should help the low end.  The MCM drivers start to fade around 50hz but are -3db at 42.  

 

There is one factor that makes the decision look better once I explain it.  It's not just the cheapest speaker, but it's also the best performing. The big factor that might be easily overlooked is the sensitivity.  The MCM driver is 10db higher than the Lab15.  The actual response of the MCM is -10db at 28hz while the Lab15 is -3db at 32hz.  To illustrate this I've overlaid the MCM freq response with the Lab15.  I can use a Biamp DSP (I have several Nexias laying around) to pull the levels down starting at 30hz and above to make it completely flat from 30hz to 100hz.  Given the Lab15s sensitivity of 88db, the MCM's in-box response is -3db at 28hz given 1w power measured at 1m and flat at 88db from 30hz to 100hz.  With the aid of the Biamp DSP the MCM drivers are -3db at 28hz with a flat response up to 100hz.  For a total cost of the drivers of less than $130.  That's the reason I am leaning toward the MCMs - not just because they are cheaper.

Emminence Lab15.png

MCM Audio Select (55-2953).png

Emminence Lab15 and MCM.png

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Be careful of the MCM drivers.  I have bought a bunch of their drivers and they aren't bad though as many point on different forums, the specs may not pan out to what is documented.  Get them home, run them in and verify.  For the cost though, dumb to not try them if they can be returned easily.

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The cabinets were designed for a specific woofer, the K33.  Crites has 2 models that were built on virtually the same specs.  These are the only ones you should use in those cabinets if you want proper performance.

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16 minutes ago, mark1101 said:

The cabinets were designed for a specific woofer, the K33.  Crites has 2 models that were built on virtually the same specs.  These are the only ones you should use in those cabinets if you want proper performance.

If they were built for those drivers, can you explain the performance and why the low end virtually disappears below 50hz?  I've attached the response graph for the K33 in that cabinet.  I was looking for a driver to extend the low end further. Even without EQ the MCM driver extends almost 10hz lower than the K33.

Klipsch K33e.png

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You should consult forum member JWC who designed the cabinets.  There were different versions.  The cabinets I have are double cornwall bass bins.  He actually took the drivers and horns and soaked them in water (in plastic of course) to get the exact displacement and built the inner volume exact to a cornwall (for each bin).  That said the original cornwall had a volume to support the K33 woofer and properly load it.  So if you change the woofer you now detune the design.  Mine are accurate down to around 42Hz.  JWC told me mostly garbage after that.  SO I don't try to get them any lower.  I use a pair of 684 subs along with them.  Maybe you need to look at different speakers if you want to go lower.

 

I will say my '73 cornwalls definitely go lower than my DBBs.  Why is that?  I have no idea.  But they have the original K33 woofers in them.  My DBBs have the Crites cast frames.

 

My MWM bass bins use the Crites stamped and I actually have always preferred the smoothness of those over the thump of the cast.

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51 minutes ago, mark1101 said:

You should consult forum member JWC who designed the cabinets.  There were different versions.  The cabinets I have are double cornwall bass bins.  He actually took the drivers and horns and soaked them in water (in plastic of course) to get the exact displacement and built the inner volume exact to a cornwall (for each bin).  That said the original cornwall had a volume to support the K33 woofer and properly load it.  So if you change the woofer you now detune the design.  Mine are accurate down to around 42Hz.  JWC told me mostly garbage after that.  SO I don't try to get them any lower.  I use a pair of 684 subs along with them.  Maybe you need to look at different speakers if you want to go lower.

 

I will say my '73 cornwalls definitely go lower than my DBBs.  Why is that?  I have no idea.  But they have the original K33 woofers in them.  My DBBs have the Crites cast frames.

 

My MWM bass bins use the Crites stamped and I actually have always preferred the smoothness of those over the thump of the cast.

 

I have the original DBB's (side ports) and run Crites cast frame woofers.

Always felt like the "thump" was what this speaker was all about.  ;)

tc

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I have LaScalas for my mains and those go pretty strong down to around 50hz.  I was hoping to use these AS a subwoofer to extend the bass from the LaScalas down lower while accenting the "thump" factor.

 

I'm going to be moving in June, so I probably won't even get a chance to set these up until after I move. I'm getting them now because the previous owner is moving and needs them gone.

 

I'll likely try the MCM driver with DSP knowing that I can return the MCM within 30 days.  I wish I could get an answer sooner, but it will likely be mid summer before I get any useful data.

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Each seperately enclosure is about 6.3 cuft tuned to approx 42hz.  You can use other drivers....

 

the design goal was to be a big cornwall...and sound like a cornwall

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