Tricks to change driver Qts. from 0.28 to 0.45

ronbrady · 2010-11-11 13:05:46

http://www.monacor.de/typo3/index.php?i … r=EN&typ=u
Hope the link works!!!!!!!!!!!

Hi Guys
I am interested in buying a pair of Monacor SP-30PATC full range drivers to replace my Eminence Beta 12lta's. Using Win Isd to model them in my 5.2 cu. ft. boxes I would have to raise their Qts. from 0.28 to 0.45. IIRC you can change a drivers Qts. by either changing the weight of moving mass (Qms.) or by changing the resistance of the driver (Qes.). Do any of you guys know of a formula or a calculator or chart that can calculate the proper amount of series resistance I would need to effect the proposed change. Also---do any of you have any experience with this driver and why don't they have a sales rep in the North America?????? So many questions.......
Thanks
Ron Brady

hitsware · 2010-11-11 13:47:20

http://www.mh-audio.nl/newqts.asp

Ron,
Be aware that resistance in series messes
up the highs (by some unknown mechanism)
A small bypass capacitor is needed to
correct for the problem.

ronbrady · 2010-11-11 14:11:35

Hi Hitsware
Thanks for the tip. I was hoping that I could use the needed series resistance to also act as a bit of a BSC. If I have to use more than say 5-6 0hms or so then the whole SP-30PATC thing looks less attractive.
Ron

PS-- Oh and thanks for the link----it looks like all I need is a big 4 ohm series resistor and the SP-30PATC will work perfectly in my 5.2 cu. ft. box. All I will need to do is change the size of the port and play with the stuffing. Sounds like fun to me.....
Ron

Last edited by ronbrady (2010-11-11 14:20:22)

hitsware · 2010-11-11 23:00:59

http://www.monacor.de/typo3/index.php?i … N&typ=full

Nifty ....................
Seriously ...
Add the resistance (on and off)
and listen carefully ..... driver open on
the table in front of you
(preferably in a quiet situation)
Then (if you hear degradation with the resistor)
Put a capacitor in parrallel and listen for
improvement ........
~ ? 1 uFd
Not to big or it defeats the resistors
affect on Qts ...

Last edited by hitsware (2010-11-11 23:02:26)

Nihilist · 2010-11-12 15:39:34

A 4 ohm resistor inline is going to drop your SPL by about 3db. That means about half your power will be wasted via the resistor.

Say bye-bye to dynamics.

Try the driver in the cabinet without any resistor using only the appropriate port adjustment. Sure, it may model as though the bass response is rolling off early, but I bet it will actually couple nicely with the room reinforcement.

I think they call it a bass shelf alignment ?

In a 5.2 cubic foot box, try tuning the port to 42-43hz. This will put the porting frequency right in the middle of the impedence peak.

Perhaps you won't like how it sounds , but it IS another option. IMO, as little as you can put into the signal path is the best option.

If your cabs are already tuned close to that , 40-45hz , then just drop it in and see how it works.

A resistor inline with a bass driver ( I know it is a FR , but it will be doing all the bass , right ?) is not a good recipe in my mind.

..............................Blake

Nihilist · 2010-11-12 15:55:17

http://img243.imageshack.us/f/monacorsp30patc.png/

Here's a link to the response . I used the T/S parameters from the Monacor website and Win ISD .

The -6db pont was 38hz.

I chose 42.4hz based on David B. Weems calculator method of bass reflex design, which holds up very well against computer modeling. It is designed to tune the port to the cabineted drivers impedence peak .

Vas/box volume (to the power of .32) x frequency of resonance = port frequency .

3.78cu.ft./5.2cu.ft. = .727099755^.32 = .903046428 x 47hz = 42.443hz

His calculator method for sealed cabinnets is very good , too.

Is there a way that Win ISD can show this same information ?

Is there a way to get impedence plots on Win ISD ?

.............................Blake

Last edited by Innerconflict (2010-11-13 04:39:34)

ronbrady · 2010-11-13 01:33:18

Thanks for the advise guys. I have not bought the drivers yet and will probably wait until after new years. I don't like the idea of using a series resistor with a large driver and I wont if I don't have to. I will play with various port tuning lengths and stuffing first. I have a pair of 50 watt rheostats (L-Pads) that I would use to see if some series resistance is needed. Generally speaking most full rangers that have low Qts. numbers exhibit a significant rising response which would benefit from some series resistance but this particular driver does not. I am hoping that the actual drivers respond as their spl curve suggests. If they do then I will do what ever is necessary to make them work. In the mean time I have replaced the 12lt's with a pair of Atlas Sound 12CX which I have been holding on to for some time now. It is interesting that there are no published T/S values for these drivers. I will provide a link below.
So far the bass driver is producing more bass than I am used to but it is not real clean, tight bass like the 12lt. The coaxial compression driver attached to it has a 2.5" voice coil and has a pleasant sound quality. The crossovers that came with them were absolutely horrible. I couldn't listen to them for more than a couple of hours without getting a headache from them.
I replaced the factory crossover with just a single capacitor driving into the tweeter through a standard adjustable L-Pad and now the sound is much more pleasing. I have been playing with several different styles of horns and it has amazed me how very different they each sound. This project should keep me tweaking through the holidays I hope. Do any of you guys have any experience with these coaxials??? www.atlassound.com/pn/12CX
Best wishes
Ron Brady
Thanks again
Ron Brady

Pit Hinder · 2010-11-13 05:29:04

Ron,

AFAIK the only sickness that can be cured by just treating the symptoms, is cholera.
"Treating" a driver with rising response by bashing it over the head with a resistor...no. "My carÂ´s got too strong an engine, so I keep the handbrake on" or suchlike?

OK, you know that I sometimes sound like a cynic. And reading what IÂ´ve just written makes me snigger - the handbrake will start giving off smoke sooner or later, and so will the resistor.

Have a nice weekend, and better weather than we got here,

Pit

hitsware · 2010-11-13 22:31:31

> Say bye-bye to dynamics

Got power ?

> handbrake will start giving off smoke sooner or later, and so will the resistor.]

Then we be kookin' ....

hitsware · 2010-11-13 22:49:30

I think you are on the right track.
' professional ' drivers ....
Those used in supermarket ( and nightclub )
ceilings are very well designed .
Since they are sold in vast quantities
they are inexpensive.
An untapped source for the
person that listens more than reads...

http://fullrangedriver.com/forum/viewtopic.php?id=1554

Last edited by hitsware (2010-11-13 22:58:00)

karlsonkab · 2010-11-14 12:22:40

that's a pretty Atlas coax for ~$238 (low price IIRC) and the little horn reminds me of the excellent Peavey coaxials. Martinsoundpro used to sell an Eminence cast frame 12" coax for ~$119 (sans high frequency driver) with 80oz magnet and edge wound voice coil that is decent. Its not listed anymore so you'd have to call. adequate HF drivers would run ~$35-$45 on sale then figure in a crossover. I had a generic Eminence crossover on 1114 and it didn't quite gel until I tried a 2X12uF 2X0.39mH allpass network on the woofer to "move" the woofer's acoustic center back a bit

http://www.google.com/url?sa=t&source=w … JQ&cad=rja

did you find a US seller for Monacor?

Pit Hinder · 2010-11-14 15:56:18

There is no "official" Monacor dealer in the US, moreÂ´s the pity. But according to Thorsten (Tech Chief) any little mom-and-pop shop can order from Bremen, Germany, whatever they think they can sell, in whatever quantity. Warranty issues no problem either.

Last edited by Pit Hinder (2010-11-14 16:53:41)

ronbrady · 2010-11-15 13:37:06

Thanks for the comments guys. Freddy---I was going to try a 1000mfd capacitor on the input to the woofer in an attempt to delay its output relative to the tweeter. The tweeter's membrane sits about 2 inches behind the woofers cone so the time alignment is way off. I have tried reversing the woofer leads and also the tweeter leads but the misalignment is just worse. So clearly the offset is less than 180 degrees. I was hoping that a large cap on the woofer my rotate the phase angle by perhaps 90 degrees and possibly get a better time alignment. I have not ordered any large value caps as of yet. Do you guys have any experience with using capacitors to help time align coaxials drivers??
Please advise.
thanks
Ron Brady

Pit Hinder · 2010-11-15 19:38:02

Ron, stop trying to be more Catholic than the Pope. Getting a wonderful step response on paper is something for geeks, enjoying the imaging of a coax is for music lovers. ManÂ´s lifespan is but threescore ten, rather go for music.

hitsware · 2010-11-15 20:47:06

Perhaps Ron has a bit of what I have.
The better it sims, the better it sounds.
( @ threescore six ) ...........

> any little mom-and-pop

If I talk my wife into it ?

http://www.quamspeakers.com/quikspec.shtml

Last edited by hitsware (2010-11-15 22:48:27)

ronbrady · 2010-11-16 02:18:18

You guys crack me up!!!! But once again I find myself being a victim of my own stupidity. I spent a large portion of last weekend trying to figure out why these Atlas CX12 could not thump harder than the meager 12lt's (which I adore still). The top third of the back of my cabs unscrews with 18 screws each. I must have had the back of those cabinets off at least 6 or 7 times during the span of the weekend. I would unplug the woofers and listen to the tweeters for a while and conclude that they sound fine and then I would hook up the woofers being careful to hook the + from the crossover board to the + post on the woofer etc.....And then I would fire them up and be disappointed that the bass was shallow etc. Well last night I turned off the system and went to bed more than a little bit disscusted with my new speakers----especially since they would not fit into the holes that the 12lt's came out of. I had to enlarge the holes by only about 1/8" all around in the house because they were too heavy to carry outside to work on. So I had to clean up my whole living room from all of the sawdust that developed from the messy resizing of the holes. Anyway I came home from work tonight determined to get to the bottom of the funny phasey nonsense that I was experiencing. I knew that the tweeters sounded fine and in phase with each other. I took out the old 1.5 volt battery and hooked it up to the woofer + and - leads and I discovered that one of the woofers was backwards. Apparently when the spade connector assembly was plastic welded to one of the woofers it was installed 180 degrees incorrectly compared with the other woofer. A simple QC oversight ruined my weekend------I was PISSED!!!!!!!!!!!!!!!!! I carefully poled both drivers and marked them with red paint and then cut the wires from the crossover and crimped on new connectors that would fit both the regular sized spade connector and the funny one which is just a bit narrower than the positive one. Thinking that I had solved the problem I hooked up my woofer according to the woofer + and - markings on the leads from the crossover and buttoned up the back panels of the speakers and put something soothing on, poured a beer over Ice in a tall glass and sat back to enjoy the fruits of my cleverness. On came the music and down dropped my jaw. The most horrible sounds came out of those speakers that I could not believe what I was hearing. Out come the screw gun and off come the back panels and this time I was serious. I immediately reversed the phase of the woofers and without putting the back panels on the enclosures I stood in front of them an realized that they sounded wonderful. WHY --OH----Why would the manufacturer label the leads on the crossover backwards????????
Truly UNBELIEVABLE!!!!!!!!!!!!! Closer inspection of the drivers (as pretty as they may look like on the outside) was a little sticker which said Made in China-----no other explanation was needed.------------------------------------OK----------------This time I installed the back panels on the speakers poured another beer and sat down, relieved but still Pissed and started the CD player!!!!!!!???????? What was going to happen??????----------The music started (a violin solo----Ave Maria-----by some little known artist. It sounded sooooo goooooood I was practically crying-----....;.....Damn--------How many times have I been screwed by speakers wired out of phase????? Well once again I survived another round of getting it wired right--stupid-----.Damn-- I sure create a lot of work for myself. Buttttttt------the music sounds pretty good even though there is an evil crossover at about 18kHz. The driver certainly out perform the 12lt's and 2.5" compression driver certainly satisfies the single driver clarity and coherence that I loved from the 12lt. The components used in the Atlas crossover are the cheapest available so I will upgrade them a bit and see it the coherence improves. These driver really rock the house though. They easily max out my Hypex 180 amp modules just before blood starts to ooze from my ears----Just Jokeing but you get the idea. This doesn't mean that I have fallen off of the fullrange driver wagen----quite to the contrary!!!!!! Variety is the spice of life as they say and I still have my Zu Druids for that intimate listening experience. The atlas drivers were accumulated over the past year or so and I really wanted to see if these efficient, potentially high Spl driver could perform in a more intimate setting and even though they are far from being broken in, I suspect that they will be up to the task. I have often wondered how the Pi speakers of Wayne Parnham must sound and now I think that I know----they are very satisfying I'll bet. Oh well thanks for letting me vent my frustration and forgive any spelling errors etc.
Best wishes
Ron Brady

Pit Hinder · 2010-11-16 18:04:49

Oh boy, some weekend! Make sure never to tinker with Italian vehicle elegtricks if youÂ´re puzzled by Chinese loudspeakers - itÂ´s worse.

Nihilist · 2010-11-18 01:18:23

Pit Hinder wrote:

Ron, stop trying to be more Catholic than the Pope. Getting a wonderful step response on paper is something for geeks, enjoying the imaging of a coax is for music lovers. ManÂ´s lifespan is but threescore ten, rather go for music.

And now what do you have to say for yourself, Mr. Pit ?

............................Blake

Nihilist · 2010-11-18 01:26:38

Ron,

It's hard to tell from the pic, but does the driver have a "whizzer cone" type horn element for the tweeter ?

How do you like them after some time with them ?

What do these puppies cost ?

.............................Blake

ronbrady · 2010-11-18 19:33:30

Hi Blake
The atlas do not have a whizzer cone. That whizzer looking thing is a hard plastic horn with a 2 inch hole through the middle of it. The voice coil is 2-1/2 inches in diameter. The pole piece tapers from about 1-1/2 inch down to 1 inch inside where the compression driver attaches at the back of the main pole piece. I have been listening to them for a few evenings this week and generally like them. I have hooked up the factory crossover which actually sounds pretty good after finally gettin the woofers phased correctly. I can hear some graininess from the electrolytics on the cross over so I have ordered some decent poly and metal film caps to upgrade the factory crossover. The speakers are still breaking in but in my living room they play really big. They were designed for a large auditorium and high wattage but at 99db they play a regular sized living room very easily. I have cranked them up and have not heard any complaints from them. So far they do not have much magic for me. They have lots of bass and full bodied voices but i don' feel a connection with them like a real fullranger can convey. They would be great for a dance party of something like that but they sound like an OK two way at this point. After the crossover upgrade I will have more to say about them but so far the best they have sounded was with the woofers hooked directly to the amp and and single polyester capacitor adding the tweeter at about 4 kHz. This was the best sound so far. However it require an adjustable L-Pad on the tweeter for that test. I will try that again later now that I have the plus and minus identified on the woofers.
Best wishes
Ron Brady

norman bates · 2010-11-19 02:43:10

I often waffle between my 4" bamboos and my klipsch 2 ways (rb75), so I understand.

Norman

karlsonkab · 2010-11-19 21:36:21

hi Ron - I'm using the network on the right with 2-12uF caps and 2- 0.39mH chokes after the lowpass section of my crossover
and it seemed to work in my case.

The 1114 cast frame Eminence-Martin coax with Selenium HF is as good as my FE206EN - just different, more efficient, and more rugged
I get good dynamics with a single single-ended EL34 Tec-on amp.

ronbrady · 2010-11-21 01:46:19

Thanks freddy
I think that is the all pass filter I am looking for. I'll bet I have enough stuff sitting around here to make up a set to try,
thanks again
Ron Brady

ronbrady · 2010-11-26 02:39:32

Hi all
Just a quick update about my experiences with the Atlas Sound 12CX. I upgraded all of the capacitors on the crossovers but I just was not happy with the out of phase problems that it introduced. No matter how I wired it to the woofer and tweeter it was not very pleasing. I eventually went back to just single capacitors and adjustable L-pads for the tweeter and let the woofer run wild. I found that if I reversed the polarity of the woofer that the phase problem went away. I am now crossing over using 4.7mfd caps and I am very pleased with the performance. Some of that full range magic is now present with the woofer doing all of the voices duty with the tweeter just adding some harmonics above 5kHz. I will continue to play with them through the holidays but now they are very satisfying. The bass and mid bass has really opened up now without anything between it and the amplifier. The tweeter is considerably louder than the woofer so the L-pad is necessary. I want to try just some series resistance for the tweeter next----My L-pads are running much hotter than they were designed to run.
Best wishes
Ron Brady

Nihilist · 2010-11-26 22:15:01

Hi Ron,

If the tweeter is 8 ohms, then it is only -6db at 2100hz. Ouch. That's AWEFULLY low for a tweeter , especially if you are throttling the volume at all. No wonder the L-pad is getting hot.

Try about half of that value (like a 2.2ufd or so) and see how it sounds. I bet you will be surprised.

.....................Blake

Fullrangedriver Forum

#1 2010-11-11 13:05:46

Tricks to change driver Qts. from 0.28 to 0.45

#2 2010-11-11 13:47:20

Re: Tricks to change driver Qts. from 0.28 to 0.45

#3 2010-11-11 14:11:35

Re: Tricks to change driver Qts. from 0.28 to 0.45

#4 2010-11-11 23:00:59

Re: Tricks to change driver Qts. from 0.28 to 0.45

#5 2010-11-12 15:39:34

Re: Tricks to change driver Qts. from 0.28 to 0.45

#6 2010-11-12 15:55:17

Re: Tricks to change driver Qts. from 0.28 to 0.45

#7 2010-11-13 01:33:18

Re: Tricks to change driver Qts. from 0.28 to 0.45

#8 2010-11-13 05:29:04

Re: Tricks to change driver Qts. from 0.28 to 0.45

#9 2010-11-13 22:31:31

Re: Tricks to change driver Qts. from 0.28 to 0.45

#10 2010-11-13 22:49:30

Re: Tricks to change driver Qts. from 0.28 to 0.45

#11 2010-11-14 12:22:40

Re: Tricks to change driver Qts. from 0.28 to 0.45

#12 2010-11-14 15:56:18

Re: Tricks to change driver Qts. from 0.28 to 0.45

#13 2010-11-15 13:37:06

Re: Tricks to change driver Qts. from 0.28 to 0.45

#14 2010-11-15 19:38:02

Re: Tricks to change driver Qts. from 0.28 to 0.45

#15 2010-11-15 20:47:06

Re: Tricks to change driver Qts. from 0.28 to 0.45

#16 2010-11-16 02:18:18

Re: Tricks to change driver Qts. from 0.28 to 0.45

#17 2010-11-16 18:04:49

Re: Tricks to change driver Qts. from 0.28 to 0.45

#18 2010-11-18 01:18:23

Re: Tricks to change driver Qts. from 0.28 to 0.45

#19 2010-11-18 01:26:38

Re: Tricks to change driver Qts. from 0.28 to 0.45

#20 2010-11-18 19:33:30

Re: Tricks to change driver Qts. from 0.28 to 0.45

#21 2010-11-19 02:43:10

Re: Tricks to change driver Qts. from 0.28 to 0.45

#22 2010-11-19 21:36:21

Re: Tricks to change driver Qts. from 0.28 to 0.45

#23 2010-11-21 01:46:19

Re: Tricks to change driver Qts. from 0.28 to 0.45

#24 2010-11-26 02:39:32

Re: Tricks to change driver Qts. from 0.28 to 0.45

#25 2010-11-26 22:15:01

Re: Tricks to change driver Qts. from 0.28 to 0.45

Board footer