Qts with series resistor to multiple woofers

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To clarify, I think kimmosto is working very hard at this, and has provided a lot of features.

As a general purpose sim (one that doesn't require targeted input), I look forward to V3. Also at present I see others misusing features and getting themselves into trouble.
 
True, it's not perfect, but it seems more flexible than a lot and the large array of features is certainly impressive. You have a particular favourite in terms of software Allen? I normally have LspCAD lurking, which I still rate, although the dongle for my copy has started acting up; will have to get that sorted at some point.
 
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Indeed it is. I've always used my own software. Before that i'd have calculator rallies (spend the weekend running responses). When a computer system would become obsolete I'd rewrite. Some years back I lost track of my work and recently I wanted to build a speaker and decided to try something available. So to me, this is less flexible than I'm used to.
 
I'm aware that adding a series resistor to a woofer will alter its Qts. I've been using this calculator to see the effect it would have:

HiFi Loudspeaker Design
My question is when adding a single series resistor to multiple identical woofers, how am I supposed to calculate the effect on Qt. What should I be putting in for Qes and Qms?
Use Unibox - you input driver parameters, the external single resistor, and the driver configuration, and the Qts will be calculated. Really easy.

Besides that, if you put two identical drivers in parallel, you obtain a single driver whose parameters are:
Fs, Qm, Qe stay the same,
Sd, Vas double
Re, Le halves

Ralf
 
Thanks very much. I assume the internal DC resistance of inductors has the same effect as a series resistor as well?

TBH, you must simulate this: Software | Visaton

I'd try a big box volume to approach open baffle: W 200 S - 8 Ohm | Visaton. Like 500L.

I have been threatening to tell the Engineer in Hell joke for a long time. :D

At last, here it is:

An engineer dies and goes to hell... due to an administrative mix-up by St. Peter at the Pearly Gates, who can't find him on his list. So sends him down.

He is welcomed by his orientation demon in Hell, who shows him around and explains how things work. The engineer notices that a lot of things aren't working and are in dire need of fixing. The air conditioning is busted, the network is overloaded, there's power shortages everywhere, everything is overheating. He mentions this to the little demon and suggests he could try to fix things. He also had a few ideas about redesigning the place to make it more efficient. The demon takes him to Lucifer, and Lucifer is enthusiastic about the whole idea and gives his permission.

A few months later God decides to visit Hell for an inspection. He is greeted by the new renovated Hell and he's absolutely speechless! The corridors are now well lit and properly ventilated. The air conditioning is working and the thermostat is fixed. The elevators are working again. There's no more loud noises of grinding and screeching coming from all the machinery. The lava spill has been contained. All the horrible fumes are now gone and the denizens of Hell use electric cars to travel. There's even a monorail being constructed. The electrical grid has gone geothermal. Cell coverage was full and there was even wifi. Not only that, but several clubs were under construction and there was already a kick-*** pool with attached jacuzzis. Some bulldozers were building a beach and a tropical-themed resort nearby. The condemned souls were enjoying their time playing sports in new gyms, walking in parks, racing with muscle cars, playing video games and doing all sorts of other activities.

God furiously walks to Lucifer's office, kicks the door open and walks in

"What the Hell is going on here Lucifer?"

"Well we got an engineer and he fixed the place up for us"

"You can't get engineers. Our contract clearly stipulates that all engineers belong with me in Heaven."

"Well too bad, I'm not giving him over"

"I'll take you to court you ungrateful bastard!"

"Ha, good luck finding a good lawyer up in Heaven!"

I can only reiterate this surprising mathematical finding about the effect of resistance on bass performance:

498265d1439427379-8-inch-woofer-bass_q_function-jpg


694604d1533073298-woofer-cabinet-designs-pitch-system7-flattish-impedance-closed-box-png


Sometimes it can help. :cool:
 
Not that surprising given that Fs, Vas are stable, and Qes (& thereby Qts) have been artificially raised, ergo larger box volume & lower Fb are the order of the day. :) Useful though as you say, or can be if you account for it in the design. For e.g., this is a set I did for the Alpair 11MS for amplifiers wit output impedances from < 1ohm - roughly 4ohms so covering the majority of the more popular SET circuits:

http://wodendesign.com/downloads/Nostromo-Alpair11ms-reflex.pdf

Can Boxsim handle any shunt resistance on the LF unit & incorporate its effect on box alignment Steve?
 
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Boxsim does what it does, IMO. By and large, it's good stuff. Particularly since Visaton include all the driver measurements, thus saving you from having to buy a microphone and all that dull stuff!

I am not solely an engineer, Scottmoose. I have other aspects.

God bless my soul, Nina Simone overcame prejudice to be recognised as a great piano player and an even better singer. This is not comfortable viewing, but it is REAL. Feel the love at the 1976 Jazz Festival in Montreux, Canada.

Let's reiterate my terrible Joke about the New Hell we have constructed:

A few months later God decides to visit Hell for an inspection. He is greeted by the new renovated Hell and he's absolutely speechless!

The corridors are now well lit and properly ventilated. The air conditioning is working and the thermostat is fixed. The elevators are working again. There's no more loud noises of grinding and screeching coming from all the machinery. The lava spill has been contained.

All the horrible fumes are now gone and the denizens of Hell use electric cars to travel. There's even a monorail being constructed. The electrical grid has gone geothermal. Cell coverage was full and there was even wifi. Not only that, but several clubs were under construction and there was already a kick-*** pool with attached jacuzzis.

Some bulldozers were building a beach and a tropical-themed resort nearby. The condemned souls were enjoying their time playing sports in new gyms, walking in parks, racing with muscle cars, playing video games and doing all sorts of other activities.

Actually sounds much like the World the BBC are constructing:

So maybe we are actually living in Hell right now! :rolleyes:

It's a worry. :)

But not much of a worry to those of us who have Faith. Or can buy a train ticket to the V&A in London.
 
Indeed; I have Boxsim myself; but it's not currently installed while I'm slowly building a new PC. I was just curious, since its lumped-element box modeller clearly accounts for the effect of series R on driver Q, whether it also accounts for any shunt resistance (e.g. if you added a 2-element L-pad rather than just a series resistor) on driver Q & thereby box alignment? If you get chance, Steve, could you have a gander?
 
Indeed; I have Boxsim myself; but it's not currently installed while I'm slowly building a new PC. I was just curious, since its lumped-element box modeller clearly accounts for the effect of series R on driver Q, whether it also accounts for any shunt resistance (e.g. if you added a 2-element L-pad rather than just a series resistor) on driver Q & thereby box alignment? If you get chance, Steve, could you have a gander?
I checked Basta! and it calculates the new driver Q with a 2-element L-pad. I haven't used Boxsim yet so I don't know.
 
Long ago, there used to voltmeters that worked kind of like loudspeakers. If you shook them, the needle went all over the place. But if you wrapped a paper clip between the terminals, quite dead.

In audio systems today, the driver is likewise connected to a dead short when it plays (AKA audio amp with damping factor over 10). A resistor of almost any resistance that would affect FR output, changes that dramatically and you immediately loose the distortion control that degenerative feedback provides.

Other than testing with Dirac pulses, I wonder how you'd see that on a FR or other familiar REW tests? So why bother with Q?

B.
 
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