Tuba 18, David, Table Tuba 8" subwoofers. Best choice?

For livingroom sound better than in a theatre.
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Krillin
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Tuba 18, David, Table Tuba 8" subwoofers. Best choice?

#1 Post by Krillin »

I need an 8" subwoofer that has an Fs, Qts, & Vas of 30 +/- 20%. Everything written here is based on the subwoofer measurements located here: https://www.dibirama.altervista.org/le- ... oofer.html

Three obvious choices are the following
1) Tang Band W8-740C - Fs 29.9, Qts .39, Vas 19.9
2) Dayton DCS-205-4 -not measured but the 10" has consistent parameters
3) MCM 55-2421 - unknown consistency

The Tang Band W8-740C is discontinued, Dayton Classic 8" has unknown distortion but the 10" has 8-9% distortion at 50hz, 24% distortion at 35 hz, when at 90db. And the MCM can fall apart when in a horn due to glue problems.

I can use some help knowing just how loud I can get with 8mm xmax in a horn and help with distortion. Some of these 8" subwoofers have 10% distortion at 50hz and up to 40% distortion at the intended F3 around 30hz. I know distortion is lower due to less excursion and every bend of the horn acts as a low pass filter lowering distortion. However, can a horn solve 8-40% distortion at the frequencies between 30-50hz?


Dayton RSS210HO-4 - Almost identical to the Tang Band W8-740C with real world measurements (Fs 29.57, Qts .43, Vas 18.47) [2% distortion @ 50hz; 6% distortion @ 30hz]
SBAcoustics SB23MFCL45-4 - Closest to spec but also the most expensive (Fs 27.3, .Qts .35, Vas 38.71) [2% distortion from 30-50hz]
Dayton DCS-205-4 - Distortion is assumed to be very high beneath 50hz but easiest to mount, cheap, good build quality
Tang Band W8-1363SB - Neodymium version of the W8-740C and better performing with horrible tolerance. Has this been the experience of anyone here? (Fs 46.1, Qts .55, Vas 13) [5% distortion @ 50hz, 17% distortion @ 30hz)

I am tempted to go with the Dayton Classic however the massive distortion on the low end is making me hesitant. Also, not sure how loud I can get with 8mm xmax vs 12mm xmax as I tend to play them full blast and leave the room when cleaning the house. I am open to any car audio subs as long as they have good tolerance, I know the often discussed JBL and Infintiy 860w subs are long gone.

Grant Bunter
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Re: Tuba 18, David, Table Tuba 8" subwoofers. Best choice?

#2 Post by Grant Bunter »

Hello and welcome :)

There's no mention on the tang band site that the W8-740C is discontinued, but I notice it's not available at parts express.
That may simply be a covid thing.
http://www.tb-speaker.com/products/sear ... no=W8-740P.
You can contact Tang band via their home page to ask, it would be good to know.

The MCM had a brief period where there were some issues, but the comments about problems seem to have ceased for a few years.

1 x T18 corner loading adds +12dB (the same as if you built 4 cabs) on baseline SPL charts.
It has more output than the table tuba.

Where are you?
Built:
DR 250: x 2 melded array, 2x CD horn, March 2012 plans.
T39's: 4 x 20" KL3010LF , 2 x 28" 3012LF.
WH8: x 6 with melded array wired series/parallel.
Bunter's Audio and Lighting "like"s would be most appreciated...

Krillin
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Re: Tuba 18, David, Table Tuba 8" subwoofers. Best choice?

#3 Post by Krillin »

I'm located in the USA. The W8 appears to be mostly out of stock overseas. With tax, covid shipping delays and shipping cost I'm looking for something closer to home.

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Seth
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Re: Tuba 18, David, Table Tuba 8" subwoofers. Best choice?

#4 Post by Seth »

First post and joined four years ago... glad to have you join in the conversation. Welcome :thumbsup:

I'm not clear whether you're inquiring about the different cabs you listed in the title along with driver choices, or whether you have (or intend to build) all of the cabs in the title and want to discuss drivers for each individual cab.

In any case, the only driver I've personally used that you have listed is the MCM 55-2421. I've beaten the piss out of the 4 I've put into cabs. IIRC, Bill has had the same driver in his own personal TableTuba, daily use for something like 10 years. Yes, I have heard of a few people having issues with theirs over the last 10 years. But, it doesn't occur to me, personally, as a driver with unknown consistency. I'd say they're about the same as ANY other well known driver out there, consistently excellent with a few random issues. No manufacturer has 100% reliability.

My recommendation is to use the MCM Driver. Even just as a baseline test driver. If it doesn't perform to your satisfaction, you have something to compare to. Ultimately, I can't see you being too much more impressed with any of the other listed drivers in comparison. If the MCM is so far off of your expectations that you're unhappy with it, I don't think you'll be happy with any driver in the same enclosure. An additional cab would be way more noticeable than another driver. Or, you may just plain need a different cabinet design to fulfill your expectations.

The cabs I've built with the MCM driver have no noticeable distortion unless they're over powered. And even then, they'll more times than not bottom out the coil on the backing plate before I hear any distortion.

I get and understand the academic and technical quandary. I do it all the time. And still, I'd recommend building with the MCM option and see what you get. Then, with actual tangible firsthand experience, decide what specific performance aspects you'd like to improve upon, if any. Consider it a low dollar baseline test driver.
Build in process - 2 WH6, one Alpha 6a loaded, one PRV Audio 6MB250-NDY loaded

Two 2x6 shorty SLA Pro's
One T39, 16", 3012LF loaded
Tall AutoTuba, 20" wide, 2x 8" MCM 55-2421
TruckTuba, 8½" wide, 2x 8" MCM 55-2421

Grant Bunter
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Re: Tuba 18, David, Table Tuba 8" subwoofers. Best choice?

#5 Post by Grant Bunter »

+1 on the MCM.
It's a measly $30
Build a T18 as wide as the plans say you can for the greatest output.
Built:
DR 250: x 2 melded array, 2x CD horn, March 2012 plans.
T39's: 4 x 20" KL3010LF , 2 x 28" 3012LF.
WH8: x 6 with melded array wired series/parallel.
Bunter's Audio and Lighting "like"s would be most appreciated...

Krillin
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Joined: Fri Jan 13, 2017 10:58 pm

Re: Tuba 18, David, Table Tuba 8" subwoofers. Best choice?

#6 Post by Krillin »

I'm building the Davids which were designed with the MCM subs in mind.

So then the MCM or Daytons will go loud without any audible distortion even with their high 25%+ distortion at 30hz (when outside of a horn). I can get the MCM's for only $60 and that's a lot better than $260 SB acoustics subs.

Thanks

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Seth
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Re: Tuba 18, David, Table Tuba 8" subwoofers. Best choice?

#7 Post by Seth »

Krillin wrote: Sun Jan 31, 2021 4:42 pm I'm building the Davids which were designed with the MCM subs in mind.

So then the MCM or Daytons will go loud without any audible distortion even with their high 25%+ distortion at 30hz (when outside of a horn). I can get the MCM's for only $60 and that's a lot better than $260 SB acoustics subs.

Thanks

I don't have any experience with the David's. But, if you have a clean signal, clean amplification, and don't push them beyond their limits... I'd say you'll be a happy camper.

Any speaker/cab will lose it's composure when pushed beyond it's designed parameters... In most cases, "Full Blast" is distortion ridden. The key to keeping distortion down is keeping the amps out of clip and enough cab sensitivity to meet your volume requirements. If you hear distortion, turn it down. If, at that point, it's not loud enough... you need either a cab with higher sensitivity or more/multiple cabs.
Build in process - 2 WH6, one Alpha 6a loaded, one PRV Audio 6MB250-NDY loaded

Two 2x6 shorty SLA Pro's
One T39, 16", 3012LF loaded
Tall AutoTuba, 20" wide, 2x 8" MCM 55-2421
TruckTuba, 8½" wide, 2x 8" MCM 55-2421

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Seth
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Re: Tuba 18, David, Table Tuba 8" subwoofers. Best choice?

#8 Post by Seth »

I assume this is for music... what kind of music do you like to listen to?
Build in process - 2 WH6, one Alpha 6a loaded, one PRV Audio 6MB250-NDY loaded

Two 2x6 shorty SLA Pro's
One T39, 16", 3012LF loaded
Tall AutoTuba, 20" wide, 2x 8" MCM 55-2421
TruckTuba, 8½" wide, 2x 8" MCM 55-2421

Krillin
Posts: 9
Joined: Fri Jan 13, 2017 10:58 pm

Re: Tuba 18, David, Table Tuba 8" subwoofers. Best choice?

#9 Post by Krillin »

Everything. Lots of Spotify playlists literally anything from the 70's to today of all genres. I would say 70% HT and 30% music but this will be mainly a bedroom setup and I don't need 20hz content for a bedroom. I'll just go with the MCM or Dayton. The high distortion numbers scared me on these small subs as my Ultimax 18 measures 3% distortion @ 20hz based on the site I linked in my first post.

I just wanted to make sure I get the full horn experience of clean bass as many people post how a THT will annihilate a RSS390HF-4 in a traditional vented cabinet. Increased output is obvious along with efficiency but also talk of how "clean" it sounds in comparison.

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Bill Fitzmaurice
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Re: Tuba 18, David, Table Tuba 8" subwoofers. Best choice?

#10 Post by Bill Fitzmaurice »

Krillin wrote: Sun Jan 31, 2021 4:42 pm with their high 25%+ distortion at 30hz (when outside of a horn)
You'd have to go well past xmax to get that result.

himhimself
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Re: Tuba 18, David, Table Tuba 8" subwoofers. Best choice?

#11 Post by himhimself »

Grant Bunter wrote: Sun Jan 31, 2021 4:35 pm +1 on the MCM.
It's a measly $30
Build a T18 as wide as the plans say you can for the greatest output.
Another vote for the MCM.
2xT30 (20", 3012LF)
2xT30 (21", 3012LF)
4xOtop J-array (Beta12, melded/straight piezos)
Truck Tuba (MCM)
Next up: 2xJack12 or family of table tubas

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Strange Kevin
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Re: Tuba 18, David, Table Tuba 8" subwoofers. Best choice?

#12 Post by Strange Kevin »

I was feeling spendy when I build my Davids so I went with the TangBands. But I've used the MCM in plenty of other builds and its always been great!

Especially if you're using them in a bedroom.
I live in a poorly insulated townhouse so my neighbors don't let me get too loud, but I'd say my Davids rarely see more than 10watts even when the neighbors aren't home.
Authorized Builder - Phoenix AZ.
Main Rig - 6 DR200s - 6 T48s (30")
SLA Pros for the smaller stuff.

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Tom Smit
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Re: Tuba 18, David, Table Tuba 8" subwoofers. Best choice?

#13 Post by Tom Smit »

I built an AT for myself, and cranked it many times with no failure or noticeable distortion. For one son, I built a TT a few years ago, and there is no failure or distortion. For another son, I built a TT a bunch of years ago, and it had the bad spider. We took the driver out and put epoxy where it was needed (found out how here on the forum, or on the internet....I don't remember). It has been fine ever since. All these cabs had the MCM driver.
TomS

jimbo7
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Re: Tuba 18, David, Table Tuba 8" subwoofers. Best choice?

#14 Post by jimbo7 »

Another vote for MCM

Like Tom, I've used a few MCM's and they did great. I've also separated a few spiders from the coils. A little epoxy and they were fine. The failures were most likely on my part since they were in a car (NO LIMITER!). Can't comment on a newer MCM driver, but in a bedroom you'll have plenty of low-end.
BFM builds:
XF212
T24 BP102 24"
2x SLA's 6-5" mids, 9- gt-302's
2x AT 14" MCM 55-2421
TrT 5" MCM 55-2421
AT 18" JBL GTO804
2x OT12 flat array
2x SLA Pro 2-Alpha 6's 2-Goldwoods
2x T39 24" 3012lf
Simplex 10 BP102

Krillin
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Re: Tuba 18, David, Table Tuba 8" subwoofers. Best choice?

#15 Post by Krillin »

I'm still waiting on my speakers cabinets to be built. The guy at speakerhardware did state he had a lot of orders which is fine.

While I wait I realized I still have my Acoustic Elegance TD6M-4 (97.5db, old version) and an Acoustic Elegance TD6M-8 (94.5db, new version) that I picked up used at good price. The project they were intended for never got started but maybe I can use them. With the AE TD6M-4 there is a dip in the response and the top end response somewhat ragged however with the aid of my MiniDSP DDRC-22D it might be possible.

What would be the impact of enlarging the baffle by an inch and using a single AE TD6M-4 with my Transducer Lab N26MGR-G? Is the MTM crossover compatible with a TM?

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