The Metronome

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#661
it would be interesting to trade findings Dave. At present I am waiting for a new ITX box to run clio, but this is top of my list of measurements to be done. I am curious to see if this "mediocre" behaviour is measurable. Just casually I have noticed how the F4 favours all my unloaded cabinets, so I know its early days for leaping to conclusions but I've a sneaky feeling that damped and loaded designs will favour low DF amps.

I also noted that the high DF cabinet I spoke about hasn't liked all the PP amps I've tried that have NFB.....

capt bludhound is on the trail.....
 
#662
This parallels the findings of the Replikon's creators. I've been (all too slowly) translating their writings.

They incorporate an empirical, trial-and-error approach to "tuning" a BVR to an amp's damping factor (and the room) until the sound "locks in" (using small wooden blocks to alter an initially oversized chamber volume until the optimal bass and imaging are reached). The tuning is done while listening, for example, to the human voice. They keep tuning until the sound is natural and the speakers completely disappear.

If you're interested: www.hornlautsprecher.de - solutions in sound (click on Kapitelübersicht > Resonanztheorie in the left-hand menu).

Google Translate is almost intelligible (note that "voting" == tuning, "chassis" == driver): Google Translate
 
#663
planet10 said:
.. dial in the damping factor from huge to none) and every loudspeaker likes a slightly different setting.

dave
Click to expand...

DF seems to be they key: no more, no less... :bulb:🙂

And in the meantime we are used to swapping between amps and speakers until we find "the right match". (Or, we just don't understand how come that some folks praise some amps or speakers, because in our system it just sounds different...)
 
#664
rjbond3rd said:
They incorporate an empirical, trial-and-error approach to "tuning" a BVR to an amp's damping factor (and the room) until the sound "locks in" (using small wooden blocks to alter an initially oversized chamber volume until the optimal bass and imaging are reached). The tuning is done while listening, for example, to the human voice. They keep tuning until the sound is natural and the speakers completely disappear.
Click to expand...

wow....I came up with the same process but using balloons with water...small blocks is definitely less messy. I hadn't followed up with different volumes for different amps though...serious food for thought.
 
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#665
Vifa P17 and/or Klipsch 10" Metronome.....experiences with this driver???

Hello,
I have a pair of Vifa P17 8ohm drivers that have been collecting dust for a couple of years now. I was wondering if anybody has tried this driver with the measurements on the tables here:
The Metronome

Additionally, if not, can somebody give me an idea of what to expect for bottom end and sensitivity using these drivers built to the specs on the table?

I have been looking for an interesting design for these drivers for some time now and these are definitely interesting. Just not too sure if they would be of good use for these drivers....I understand they are very good. I was going to use a simple series crossover with some decent tweeters like Dayton's 1 1/8" tweeters.

Also, I have 8 (yes that's right eight) Klipsch K-1077SB 8" woofers that at the moment are also collecting dust. The T/S parameters for these are attached as a .pdf file. I was wondering if somebody here could help me model a Metronome for these. I have no idea if the T/S values are good for a design like this but I know Klipsch are usually pretty high sens speakers.

These were basically given to me, I think I paid about $150 for all 8 and they appear to be very high quality. They have cast polymer frames and look to be very well put together.

Of course I will never use all 8 of them and figured if I could design a metronome with them and there was more interest I would sell the rest of them for really cheap to anybody interested.

Thanks for all your help,
Jeff
 

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#666
jmillerdoc said:
I have a pair of Vifa P17 8ohm drivers that have been collecting dust for a couple of years now. I was wondering if anybody has tried this driver with the measurements on the tables here:

Additionally, if not, can somebody give me an idea of what to expect for bottom end and sensitivity using these drivers built to the specs on the table?
Click to expand...

This Met would hav ebeen a special request by someone... i can check my archived email and see if i got any reports back...

Attached is the sim... sensitivity will be whatever the sensitivity of a P17 is (less any BSC). F10 in the neighborhood of 35 Hz.

If you want to go nuts with the Klipsch, you could uses one on each side. Sensitivity of their drivers are usually optimistic.

dave
 

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#669
Hi all. As a long time lurker, I have managed to read all the posts (67 pages 😱 ).
I am considering building the Metronomes as I like the styling as well as the philosophy behind the design. I have a driver and crossover set from a pair of B&W DM23 cabinets that suffered an awful fate when sitting in a flooded basement, so I was wondering if they would be suitable. I don't have parameters for them and info is hard to come by, but the bass driver is an 8" crossing over at 900Hz to a 3" mid which crosses over at 4.5kHz to a 1" soft dome.
Is there any problem with disturbing the inner chamber by having the mid (which has its own sealing cup on the back) extending into the inside?
If anyone has ideas on Metronome dimensions that would work with these drivers, I would be eternally grateful.
My last speaker build was 30 years ago (Chris Rogers PRO9TL Mk1 which I still use).
Amp is a typical Pioneer HT of 100W/ch for main duties, but I have a little ECL86 SE tube amp as well. Music tastes vary from modern jazz (Rippingtons, Spyrogyra etc) to rock, and even the occasional classical and folk foray.

Thanks in advance, Gary.
 
#671
planet10 said:
Gary,

The T/S will be required... they are fairly easy to measure.

The Subwoofer DIY Page - Measurements

dave
Click to expand...

Thanks Dave,
I don't have a digital freq counter, but I can get reasonably close on a handheld scope. Looks like Fs is about 43Hz. I'll do the others once I can rig up and measure my amp to make sure I know its characteristics more closely.
Do I need to do the Vas measurement? I still have one usable DM23 cabinet, so I could use that one and roughly block the other holes in it. No damping material I assume?

Gary
 
#673
Thanks for the link. I also found a sine gen program for the computer and fed the amp with that, hopefully more accurate frequency wise.
Ok, I think I have the right T/S figures now:

Fs = 39Hz
Vas = 2.72 cu.ft
Qms = 1.97
Qes = 0.54
Qts = 0.42

I hope these make sense for this type of driver.
I've never done detailed speaker measurements before, and was really surprised that the Fs in the original DM23 cabinet (sealed) went all the way up to 90Hz but I suppose they are fairly small and are normally BR ported.

Gary.
 
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