OB Newbie- questions

Lazz · « **on:** 18 Jun 2007, 10:01 am »

Built speakers before, but never OB. Was thinking about using a 12 or 15 inch coaxial for mid and upper duties or would a 8 to 10 inch be better with 2x15 inch for bass duties. Was thinking about possibly either a Eminence /Selinium / Radian / B&C / Beyma /Paudio or possibly if i can get a Tannoy DC.What about Visaton B200's. Wondering what the sound quality is like compared to each other and any other possible contenders. What does the inbuilt cd tweeter compare like to say, a normal tweeter? Was thinking about maybe using the Dayton RS 15's or TC 1000's or Mach 5 audio Maw 15{quite cheap} or Fi Car audio Q15 or IXL18 for bass. How would two of these per channel in parallel work with the above in regards to sensitivity?I've been comparing a list of woofer comparisons from the cult of ib and the TC's seem to have huge displacement.The design will be based loosely around the Jamo r909,BD design Quasar. Thx. P.S what about this brand http://www.reaudio.com/
I have posted this question also on the HT Guide forum.THX.

gooberdude · « **Reply #1 on:** 18 Jun 2007, 02:51 pm »

I'd go with the Hawthorne Auggies for the bass, they are incredible.

One of the benefits (this may not be across the board...) of OB bass is that they may not need to be stereo. With the Auggies, many guys run a single plate amp and run them in mono, even though there's a pair of them.

From what i've been reading, there aren't any or many large OB specific woofers...

I rock the full Hawthorne SI + Auggie set-up, and won't be changing speakers for some time...the combo is way too much fun and has none of the set-up hassles that i read about with other drivers. If its your 1st foray into OB, keep it simple and enjoyable. the Hawthorne system is my 1st OB attempt. it might be my last too.

holdent · « **Reply #2 on:** 19 Jun 2007, 02:13 am »

I also have the Hawthorne Silver Iris coaxials but have paired them with Eminence Alpha 15As. The Alphas are much cheaper than the Hawthorne Augies (< $60US compared to $150 for the 15" Augie or $125 for the 10") and almost as good. Martin King used them in his Project 7 (http://www.quarter-wave.com/Project07/Project07.html - scroll down to "First System Update") with very good results.

In general you pay for what you get. One Hawthorne Augie is better than one Alpha but you can get two Alphas for less than the price of either Augie. I've also tried two Goldwood GW-215s (at <$29US) which are 15" pro sound woofers as well. They have a very high Qts (1.86 according to the PartExpress website) and are very cheap. They aren't as good as Alphas and can run out of steam with relatively little power; in this case two GW-215s are not as good as one Alpha.

The very high Qts of the GW-215s means you can use a very narrow baffle for an OB (I used 18" by 36" baffles with the GW-215 9" up from the base). I had very pleasing results pairing them with HiVi B3N fullrange drivers crossed over at 500 Hz. They made for an excellent "poor man's" OB but have limited power handling. Of course the Alpha 15As paired with the B3Ns were even better; and similarly the Silver Iris' with Alphas were better than that.

I haven't tried any IB-specific woofers, like the Dayton IB385, because their Qts is lower. They need to either be installed in an IB-specific situation (ie. mounted in an attic and firing into a listening room) or, if used in a OB, need to have bass boast to avoid early rolloff of the driver. A number of users have reported excellent results using the Visaton B200s paired with helper woofers (see the Decware forums and elsewhere). Visaton's design has an OB design for the B200 at http://www.visaton.de/en/bauvorschlaege/breitband/noboxbb/bauanleitung.html. Virtually any good fullrange driver can be paired with the appropriate woofer for great results in an OB.

You also asked about built-in tweeters... The Silver Iris uses a compression tweeter (actually an Eminence ASD1001S) with a custom-built 15" woofer (also sourced from Eminence) and comes with a specialty, high quality, crossover. The benefit of this design is that the driver acts as a point source. The trade-off is that any coaxially-mounted tweeter will have its frequency response modified by the woofer its mounted in -- the woofer cone acts as a wave guide.

The parts quality of the Silver Iris is excellent and you can't beat the price doing it yourself. These drivers have a smooth laid-back sound. I am very impressed with this product and recommend it highly.

ttan98 · « **Reply #3 on:** 19 Jun 2007, 03:12 am »

Holdent,

From your experience using OB drivers, you contribution is interesting and worthwhile.

gooberdude · « **Reply #4 on:** 19 Jun 2007, 04:41 pm »

Hey Holdent,

have you performed any of the tweaks for the SI's?? screenectomy, felting, grounding the baskets, etc?

i just ordered a set (4) of the baffle mounting plates from hawthorne, the same method used to attach the Drivers in the Solo and Duet frames. My baffles are pretty much done & its gonna be interesting to listen how a normal driver mounting (drivers screwed into the baffle) will perform against the hawthorne method...all else remaining constant.

mcgsxr · « **Reply #5 on:** 20 Jun 2007, 12:07 pm »

Lazz, welcome to AC, and more specifically, welcome to the OB area!

I run a set of the Mach 5 Audio 12's, and am thoroughly impressed. I run them with 1 VC open, to effectively double the QTS, and that creates a very good, cheap, OB 12. The 15's are what I SHOULD have bought, I just keep wondering!

I run them with Visaton b200's, check my Gallery for various photos.

I hear excellent things about the Silver Iris, but have never had the pleasure myself.

ttan98 · « **Reply #6 on:** 20 Jun 2007, 01:00 pm »

mcgscrx

"I run them with 1 VC open, to effectively double the QTS, and that creates a very good, cheap, OB 12. "

can you be more specific how do you double your Qts?, what is VC?

thanks

Bob in St. Louis · « **Reply #7 on:** 20 Jun 2007, 04:10 pm »

Quote from: mcgsxr on 20 Jun 2007, 12:07 pm

I hear excellent things about the Silver Iris, but have never had the pleasure myself.

I can't recommend them highly enough Mark, wonderful sound.

Bob

gooberdude · « **Reply #8 on:** 20 Jun 2007, 04:14 pm »

Don't forget the Auggies. that's a 1, 2 combination with special synergy for sure. The SI's are good on their own but great when paired with their sibling.

mcgsxr · « **Reply #9 on:** 20 Jun 2007, 05:19 pm »

Sorry, without using short forms:

The Mach 12 and 15 etc are all dual voice coil (VC) drivers.

By connecting only 1 of the 2 voice coils, you effectively double the QTS.

Using both voice coils, the Mach15 for example, the QTS is 0.32. By connecting only 1 voice coil, that number doubles to 0.64, VERY close to the "optimal" 0.7.

Cheap, good specs, amazing build quality, cast basket, great XMAX, and local for me. Perrrrrfect.

Yes Bob, I look forward to when I can hear the Iris, I do!

D OB G · « **Reply #10 on:** 21 Jun 2007, 01:30 am »

Adire Audio (http://www.adireaudio.com) mention what they call an RDO (resistively damped operation), an idea that has been around before(Ron Ennega, Brian Steele, and others).
Basically, when a driver is used that has two voice coils, a potentiometer can be placed across one, unused, voice coil.
This means that the Qts is not limited to the single voice coil value, or the double voice coile value, and can be adjusted to anything in between.
So a precise Qts can be achieved.
Unfortunately there aren't many dual voice coil designs around.
Focal used to make few, but I'm not sure if they do now, or if they would be avilable.

mcgsxr · « **Reply #11 on:** 21 Jun 2007, 02:12 am »

Car audio is where all the DVC designs are...

ttan98 · « **Reply #12 on:** 21 Jun 2007, 02:19 am »

mcgsxr,

I can get a similar subwoofer with 2 VCs locally, it says it has 2,4,8 ohms connections ie parallel, single and series respectively.

Can you generalise that I can can get a similar doubling of Qts by just using 1 VC here? Any advice here.

mcgsxr · « **Reply #13 on:** 21 Jun 2007, 01:01 pm »

You absolutely will always get double the QTS by using a dual VC with only 1 VC connected.

What are the other specs for the driver?

FS
XMAX
QTS

Good luck!

ttan98 · « **Reply #14 on:** 21 Jun 2007, 01:11 pm »

mcgsxr,

thanks, I could not get any specs out of them so i drop the idea.

stereogeek · « **Reply #15 on:** 23 Jun 2007, 09:14 am »

Hey Holdent-

Was wondering where and how you are crossing over the Alpha's to the SI's.I'm going the same route,trying for a one amp solution.

Thanks,Steve

Lazz · « **Reply #16 on:** 30 Jun 2007, 02:04 am »

Trying to narrow down my search for bass drivers going by experience or specs which would seem to be better? Ficar audio SSD18

DUAL 1 | DUAL 2

Fs: 24.7 Hz | 24.3 Hz
Re: 0.75 Ohms/coil | 1.5 Ohms/coil
Qms: 4.88 | 4.96
Qes: .75 | .69
Qts: .65 | .61
Mms: 296g | 308g
Cms: 0.14mm/N | 0.14mm/N
Sd: 1210cm^2 | 1210cm^2
Vas: 285 l | 285 l
Spl: 89.4dB 1W/1m | 89.6dB 1W/1m
Bl: 9.3 N/A | 14.1 N/A
Xmax: 21mm
Rms: 800W
Sealed box: N/A cuft
Ported box: 6-10 cuft @ 33Hz
Sub OD: 18.500”
Cut ID: 16.750”
Mounting depth: 9.500”
Displacement: 0.22cuft

Product code: 01918

Price: $ 239.00
*shipping is included

Power Handling: 800 watts RMS

Sensitivity: 89db (2.83 volts)

Impedance: 4 Ohm Nominal (SVC)

Dimensions

Outside Diameter: 46.2cm (18 3/16")

Mounting Diameter: 42.4cm (16 11/16")

Depth: 24.8cm (9 3/4")

Recommended Box Sizes

Sealed: 130 litres (4.6 cu. ft.)

Ported: 200 litres (7 cu. ft.) 19Hz tuning

EBS: 350 litres (12.4 cu. ft.) 15Hz tuning

Mach5 audio IXL-18.4
T/S Parameters

Fs = 17.7 Hz

Re = 3.4 Ohms

Qes = 0.39

Qms = 5.59

Qts = 0.37

Mms = 434.3 grams

Rms = 8.69 kg/s

Cms = 0.184 mm/N

VAS = 274.1 litres

Sd = 1029.2 cm2

Xmax = 22 mm

Cone Diameter = 36.2 cm

gooberdude · « **Reply #17 on:** 30 Jun 2007, 05:41 pm »

Go with the Auggies from Hawthorne aa

you won't be disapointed by a subwoofer that's designed to work in OB. Throw in a single plate amp, run 'em in mono and have a great summer.

navin · « **Reply #18 on:** 13 Jul 2007, 10:27 am »

Quote from: D OB G on 21 Jun 2007, 01:30 am

Basically, when a driver is used that has two voice coils, a potentiometer can be placed across one, unused, voice coil.
This means that the Qts is not limited to the single voice coil value, or the double voice coile value, and can be adjusted to anything in between.
So a precise Qts can be achieved.

from what i understand the Qts can be varied over a relatively smallish range. The extremes would be is one coil was open or short. So to expereince both extremes all one needs is a short wire.

BTW this is my first post on this forum. I am looking for ideas centered around using 2 Augie 15 for the bass, a Supravox 165 or Vistaon B200 for the mid and a Neo or 2 x OW1/OW4 for the HF.

markC · « **Reply #19 on:** 13 Jul 2007, 09:46 pm »

Welcome aboard! Why 2X ow1/ow4? Where do you plan on xing over the mid driver?