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Mark_Seaton

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Reply with quote  #61 
Quote:
Originally Posted by Sevenfeet
I wanted to give the forum a follow-up on my experience getting my UFW-12 repaired.  In short, Sandbagger rocks!

My UFW-12 has a relay circuit on the power supply fail, causing the unit not to perform.  On Sandbagger's (Kevin) direction, I removed the amp and sent it back to him for repair and his mods to improve the performance of the unit.  The UFW-12 is never going to have the bass extension of a MFW-12 or other ported subs, but I was looking forward to seeing if the UFW-12 wouldn't roll off like a cliff under 30 hz as it had been known to do.  I got the unit back weeks ago but due to family commitments, I haven't been able to do any real testing with an SPL meter until now.  My tester is the old tried and true Radio Shack analog SPL meter, purchased over a decade ago.  It needs a few tweaks to account for its own errors, but it's close enough for the purposes of this test.

I used track 16 from the venerable Stereophile "Test 2" CD that sends a test tone measured in 1/3rd octaves from 200 hz down to 20 hz.  Since my family is in the house, I decided to keep the volume in the 70-75 db range.  What I found was that on the low end, the UFW-12 is now capable of reproducing a test tone at about 72 db at 25 hz, the same as I was getting from my system at 160 hz-200 hz (+/- 3 db).  At 20 hz, the pressure rolls off to about 63 db, but that's still much better than I was seeing before.  What I wasn't expecting was a big spike in the middle range.  Between 40-63 hz I was seeing volumes in the 82-84 db range.  I was hoping that Audyssey on my Denon X2000 would have smoothed out this spike more, but my experience tells me that this is a fantasy.  The UFW-12 allows for some tweaking, but I'm going to have to go back to the manual and check to see exactly what I can try to manage with the rear controls.  (Any suggestions would be appreciated).


Hi Sevenfeet,

Don't underestimate the extension of the UFW-12.  In most rooms the modified version will extend lower than a standard MFW-15, while giving up some in max output, and a bit more vs. the Turbo version.  A few points...  Are the numbers you mention above directly read from the meter?  If so, it sounds like you may have little to no roll off down low, as the C-Weighting purposely applies a significant roll off on the lowest frequencies.  There are some spreadsheets & charts available to compensate if you do some quick searching.  Secondly, you will need to re-run Audyssey with the updated UFW-12.  The response is plenty different from the stock unit.  You also need to go back into the speaker setup menu after running Audyssey to check what it did to the crossovers and small/large settings.

Finally, double check the PEQ filter is set near 0dB, which is at some middle range of the dial, not either extreme.


One other thing I did was do some measurements on my two channel rig, which consists of a Audible Illusions Modulus 3 tube pre-amp (recently back from major repairs and new tubes), a McCormack DNA 0.5 amp, and SoundWave Grand Soliloquy towers (all of this equipment is circa 1994).  I had purchased this equipment from a friend who had purchased it from another friend over a decade ago.  The measurements of the Soundwaves was interesting....everything was more or less level from 200 hz downward to 63 hz where at 50 hz the measurements dropped 10 dbs to the 62-64 db range.  Accounting for the measurement errors in the Radio Shack meter, the speakers keep this volume steady down to about 25 db's where it drops again a bit at 20 hz.  In many ways, these are good numbers for 20 year old analog equipment, but a sub coming in at the 60 hz mark might do some good augmenting the sound.

And the UFW-12 is the obvious choice for the application, given it's ability to now extend properly under 32 hz (low C on a pipe organ).  The problem is going to be that since this is a true analog system, bass management is pretty much nonexistent so I'm going to have to calibrate carefully.  The Modulus 3 has two sets of amp outputs, so I don't need the ability to pass through a signal to an amp (which the UFW-12 can't do anyway).  Since the SPL levels under 63 hz are pretty consistent, it may be easier to match a sub to fill in what the mains cannot do at the same level of amplification.

But if I can repurpose the UFW-12 toward a strict music application, I can replace it in the home theater room with a proper ported sub to rock movies, so there is some incentive for the project.

Placement of speaker & subwoofer has a huge impact on the response.  As you note, it does sound like the UFW-12 could really help augment the bottom of your speakers.  Experiment with lowering the crossover to ~30-65Hz and play with the level a good bit.  Even better would be to grab one of the USB mic's and get REW working for less than $100.

Enjoy!

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Mark Seaton
Seaton Sound, Inc.
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Sevenfeet

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Reply with quote  #62 
Quote:
Originally Posted by Mark_Seaton

Hi Sevenfeet,

Don't underestimate the extension of the UFW-12.  In most rooms the modified version will extend lower than a standard MFW-15, while giving up some in max output, and a bit more vs. the Turbo version.  A few points...  Are the numbers you mention above directly read from the meter?  If so, it sounds like you may have little to no roll off down low, as the C-Weighting purposely applies a significant roll off on the lowest frequencies.  There are some spreadsheets & charts available to compensate if you do some quick searching.  Secondly, you will need to re-run Audyssey with the updated UFW-12.  The response is plenty different from the stock unit.  You also need to go back into the speaker setup menu after running Audyssey to check what it did to the crossovers and small/large settings.

Finally, double check the PEQ filter is set near 0dB, which is at some middle range of the dial, not either extreme.



I'm aware of the issues concerning the Radio Shack SPL meter although it's even years since I cared about the details.  I did find some of the compensation documents (but I have to download the spreadsheet out there somewhere).  I wasn't trying to be absolutely precise today since I don't have a quiet house to myself.  I had thought I'd rerun Audyssey when the sub amp came but I'll run it again, just to be sure.  Nevertheless, I'm pleased since the UFW-12 without mods clearly couldn't handle some lows quite like this.

Quote:
Originally Posted by Mark_Seaton


Placement of speaker & subwoofer has a huge impact on the response.  As you note, it does sound like the UFW-12 could really help augment the bottom of your speakers.  Experiment with lowering the crossover to ~30-65Hz and play with the level a good bit.  Even better would be to grab one of the USB mic's and get REW working for less than $100.

Enjoy!


Placement of the sub is a big deal.  I should note that when I was doing all this, I was measuring not at the primary listening point but at a point about a meter away.  So now I'm thinking all my stuff today was a bit of a crock [smile]  Anyway, I went back and remeasured at the primary seating position.  I'm still seeing a bump in the sub's performance between 40 and 63 hz, (but not as loud as before) which will need some more investigation.  Most of the other measurements were within a +4 range of 70 dbs.  That means I'm not seeing a much of a rolloff until under 25hz, and even at 20hz it's within reason (mid 60's, adjusted) for what I would expect of a sealed sub.  Not bad at all. [smile]

I've gone ahead and downloaded REW (the latest version finally seems gets past the Java sound library issues on the Mac).  In lieu of spending money on a new mic, I'll use the Radio Shack SPL for the time being and let the program correct.  That will be "close enough" for the time being.

I'll let you know what I find.


Klong

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Reply with quote  #63 
Hello all. I was recently at Axpona and was blown away by some of the setups I saw last weekend. It inspired my to fix my two dead sub amps.

I was hoping someone could assist me. Not having the funds right now for a new sub, I needed to replace two of my UFW-10 amps. I purchased 2 dayton SA-250 plate amps from parts express. The first sub install in sub #1 went fine as the binding posts were positioned out of the way of the cabinet bracing and was easy to access.

Sub #2 however, has its binding posts positioned at 6:00, almost dead center behind the cabinet bracing. My hands are too big to get back there to depress the binding post and insert the respective + and - wires.

I've tried almost every way i could think of to bend my wrist to get to the &$?!" binding post but i can' t. I've even tried rotating the driver, but it seems glued in place. I think rotating the driver may be my best bet, but it seems stuck. Anyone have any other ideas?

Thanks,
Karl
sandbagger

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Reply with quote  #64 
you might be able to use a screw driver or ruler to push the binding posts down and get the wire in.

To get the driver out take all the screws out the front and give it a smack on the back from inside.  there should not be anything really sticking it in, but the cabinet finish might have not been dry/cured?   if you really have to hit it hard I would use a long screw driver and place it as close to the cutout as possible.

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Klong

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Reply with quote  #65 
A long screwdriver and a couple of light taps with a rubber mallet was all I needed to push out the driver. I'm back in business. Thanks for the suggestion Kevin!
jewel942

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Reply with quote  #66 

Hi I found today that my daughter has pushed in both of my RS150 tweeters.  Are these still available?  The RS150s are serial numbers 00253/00254.

If not, does anyone have a couple used for sale?  Or is there an upgrade tweet available, like the Vifa ring radiator (with requisite crossover adjustments)?

I also have an RSC200 'Bigfoot' center channel that I am not using if anyone might be interested.  Has very low hours, just too big for my theater setup and has been sitting in a closet.

Thanks!

Stereodude

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Reply with quote  #67 
Have you tried the vacuum trick or tape yet?
Hondo5

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Reply with quote  #68 
I own a set of Rocket RS 850s that I purchased just as the company was starting to head south.  I bought them because of their excellent reviews, but had no idea that Mark was designing them with Chinese drivers.

So it's now 2017, and I have one speaker that has a low-frequency driver that has given up the ghost and is now buzzing badly at certain frequencies.  I'm wondering if anyone can give me an idea of what it will cost to replace that single driver on the bottom of the array, or whether it can be replaced at all.

Everything was going swimmingly with AV123 until just after I purchased my 850s and HT set-up.  Then it all started heading south.  I was promised some bookshelf speakers when I made my purchase, but never got them, and instead was offered a small sub-woofer as a switch, which didn't please me.  So it goes.

What I need right now is a low-frequency driver for my right speaker.  Can someone help?
sandbagger

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Reply with quote  #69 
I am just going to post this here as every now and then I get an email about 850 drivers.  Same goes for the 1000's and 750

AV123 basicly copied the HiVi  MxN series drivers for most of their speakers, but some have a crazy impedence and cant be matched with anything stock.
a Vifa tweeter listed below was also used in most of the speakers.

 

The 4 woofers are the same https://www.parts-express.com/hivi-m5n-5-aluminum---magnesium-midbass--297-436

The only difference is the cone color(paint if you want) and these are magneticly shielded, but no sonic differences

 

This is your mid https://www.parts-express.com/hivi-m4n-4-aluminum---magnesium-midbass--297-434

 

And tweeters are https://www.parts-express.com/peerless-by-tymphany-xt25tg30-04-1-dual-ring-radiator-tweeter--264-1016


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Reply with quote  #70 
Kevin -

THANK YOU so much for this information.  I have ordered two drivers - one to repair my RS850, and one as a backup.  Out of curiosity, do you have a recommended upgrade to the RS850 tweeters that provides better performance than the existing Viva tweeters installed?
jewel942

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Reply with quote  #71 

The stock ring radiator is a very good tweeter, not sure what you would gain in a Rocket design by changing, but here goes.

Upgrade options in similar design would be in the line of Scan Speak ring radiators, the Discovery being similar in appearance and the lowest cost ($50-60 at Madisound), although still made in Europe (Denmark). I haven't compared directly to the Vifa so no idea if you would find an improvement.    https://www.madisoundspeakerstore.com/ring-radiator-tweeters/scanspeak-discovery-r2604/8320-1-tweeter-ring-radiator/ https://www.madisoundspeakerstore.com/ring-radiator-tweeters/scanspeak-discovery-r2604/8330-tweeter-dual-ring-radiator/ (dual magnet, higher sensitivity) 

The Illuminator (~$140) and Revelator (you don't want to know but a lot more) are really good albeit pricey. Illuminator is small diameter mount so would have to rig up an adapter plate or something in the Rockets. I have tried the Revelator in an open baffle speaker I worked on with a friend, worked great although we ended up with an AMT type as the flush appearance was preferred in our application.

These might be interesting to try as they come on a round plate mount, didn't check the diameter versus the Vifa- I'll leave that to you. http://www.parts-express.com/dayton-audio-amt2-4-air-motion-transformer-tweeter-4-ohm--275-092 http://www.parts-express.com/fountek-neocd10-ribbon-tweeter--296-701 http://www.parts-express.com/aurum-cantus-g2si-ribbon-tweeter--276-400 https://www.parts-express.com/hivi-rt13we-isodynamic-tweeter--297-421 http://www.madisoundspeakerstore.com/ribbon-tweeters/hi-vi-rt1.3we-isodynamic-tweeter/

Metal dome option? https://www.madisoundspeakerstore.com/horn-tweeters/seas-prestige-27tbcd/gb-dxt-h1499-tweeter/

Or maybe... http://www.madisoundspeakerstore.com/diamond-dome-tweeters/seas-excel-t29d001-diamond-dome-tweeter-matched-pair/  [smile]

 

sandbagger

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Reply with quote  #72 
The biggest problem is any change to the tweeter is going to require a new crossover network.    if you just bolt in a new tweeter there is no idea what you might get
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jewel942

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Reply with quote  #73 
Agree of course. There are some with characteristics pretty close to the Vifa, which might be workable with minimal changes. Others not so much. YMMV
Hondo5

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Reply with quote  #74 
Quote:
Originally Posted by Hondo5
Kevin -

THANK YOU so much for this information.  I have ordered two drivers - one to repair my RS850, and one as a backup.  Out of curiosity, do you have a recommended upgrade to the RS850 tweeters that provides better performance than the existing Viva tweeters installed?


Thanks all for your information.  I received and installed the bass driver yesterday and it appears to be doing the job.  Interesting that the flange that fits into the slot on the front of the speaker cabinet is just a smidge smaller on the replacement driver than the original, but it fit.

The Vifa is okay, but my preference is for something a little brighter and more forward.  I'll probably leave it as is because it's a good match to the other speakers, but if I have some spare change rolling around on the car floor one day, might decide to experiment with an upgrade.  The RS850s are very laid back by nature, but throw a large, three dimensional sound stage.  I was listening to Beethoven Symphony No. 8 conducted by Blunier of the Beethoven Orchester Bonn (a SACD) last night on the Oppo, and kept wanted to turn it off and go to bed, but couldn't.
jewel942

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Reply with quote  #75 
The Vifa tweeter isn't laid back by nature. The frequency response of the Rockets was intentionally shelved downward on top by the designer. As the tweeter is more efficient than the woofer, there should be a resistor network in front of the tweeter to reduce the level. You can experiment with lower value in the series resistor and correspondingly higher value in the parallel resistor, or put in an L pad, to raise the tweeter level to your liking.
Sevenfeet

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Reply with quote  #76 
Quote:
Originally Posted by sandbagger
I am just going to post this here as every now and then I get an email about 850 drivers.  Same goes for the 1000's and 750

AV123 basicly copied the HiVi  MxN series drivers for most of their speakers, but some have a crazy impedence and cant be matched with anything stock.
a Vifa tweeter listed below was also used in most of the speakers.

 

The 4 woofers are the same https://www.parts-express.com/hivi-m5n-5-aluminum---magnesium-midbass--297-436

The only difference is the cone color(paint if you want) and these are magneticly shielded, but no sonic differences

 

This is your mid https://www.parts-express.com/hivi-m4n-4-aluminum---magnesium-midbass--297-434

 

And tweeters are https://www.parts-express.com/peerless-by-tymphany-xt25tg30-04-1-dual-ring-radiator-tweeter--264-1016



So the 4" part is the woofer for the 750s?  I ask since my autistic son has damaged a few of mine over the years (I have four 750 towers).  Up until now all the damage has been superficial and I keep the screens on to keep his attention away from them.  But at some point recently he put a finger through one of them (not easy to do).

The color of the units doesn't matter much, especially since they will be behind the screens anyway.  So if it is indeed the correct size, I'll buy a few of them and get to work.
Hondo5

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Reply with quote  #77 
Quote:


So the 4" part is the woofer for the 750s?  I ask since my autistic son has damaged a few of mine over the years (I have four 750 towers).  Up until now all the damage has been superficial and I keep the screens on to keep his attention away from them.  But at some point recently he put a finger through one of them (not easy to do).

The color of the units doesn't matter much, especially since they will be behind the screens anyway.  So if it is indeed the correct size, I'll buy a few of them and get to work.


As I posted above, aside from the cone color and smidge smaller flange, these basically drop right in as replacements.  Can't speak to the impedance, since I don't have the equipment to measure and it wasn't identified on the speaker.  But it seems to work as advertised.

I also picked up the MFW sub that Mark designed shortly before the company went under, but after the first didn't work, and the second amp Mark sent me also didn't work, I decided against a sub from AV123.  That's sort of consistent with Chinese electronics - quality control.  Finally ended up with a Hsu VTF3 MKII, which I'm very happy with.

So let me post another question.  Is there a good replacement to the internal MFW amp Marking was using in those subs?
Sevenfeet

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Reply with quote  #78 
Quote:
Originally Posted by Hondo5


As I posted above, aside from the cone color and smidge smaller flange, these basically drop right in as replacements.  Can't speak to the impedance, since I don't have the equipment to measure and it wasn't identified on the speaker.  But it seems to work as advertised.


Sounds good.  I'll order about 4 units.  And I'll put one of them and the outgoing one on an multimeter and check the resistance.
Hondo5

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Reply with quote  #79 
Quote:


Sounds good.  I'll order about 4 units.  And I'll put one of them and the outgoing one on an multimeter and check the resistance.


That would be helpful.  I seem to remember the 750s and 850s were supposed to be 6 ohms, and I wonder if the replacement speakers are 8.
Sevenfeet

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Reply with quote  #80 
Quote:
Originally Posted by Hondo5


That would be helpful.  I seem to remember the 750s and 850s were supposed to be 6 ohms, and I wonder if the replacement speakers are 8.


The entire speaker is supposed to nominally be 6 ohms....not sure what an individual driver is supposed to be.  The center channel RSC200 was a 4 ohm design.
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