Speaker emulator designs?

[TigerG]

Anybody have any good, simple speaker emulator/simulator designs? I've found a few schematics on line, but I'd like to see a few more for comparison.
Thanks and Happy Holidays!

[Old Tele man]

...both Steve Bench and Randall Aikens have excellent articles and designs on this subject...check out their websites.

[TigerG]

Thanks, I'll check 'em out.

[teemuk]

http://www.herby.kielce.pl/~piter/konstr/cabsims.htm

[Old Tele man]

...wish I could read the text...looks like one of the Slovak languages but I have no idea which.

...the "schematics" are all op-amp circuits configured to "emulate" specific amp/spkr combinations.

...was your original question about a "amplifier circuit"-emulation or an actual "speaker"-LOAD?

[TigerG]

Yeah, interesting post, but a bit mysterious with the language barrier.

My original question was about a speaker load. I'm having problems with a buzzy speaker-lead line out.

[dai h.]

for a tube amp you need a proper load on the output, plus additional circuitry to EQ the signal (after you drop it to line level) to make it sound like a speaker. The Aiken article is just for the load part (more sophisticated than a simple resistive load) and not the filter part (the article already mentions this though). It would probably be easier to buy a commercially avail. spk. emulating filter(maybe a Behringer?). Other possibilities might be a SansAmp(supposedly works well if you roll off the highs), a Pod, or no amplification (just plink away unamplified).

[petemoore]

Checkout Runoff Grooves Cab Sims.
Jfet etc.
Two pole, LP filter...[there's one at the end of 'Thunderchief or Thor'.
Much of the idea for the HF filtering is...get a 'sharper' high freq cut [more db per octave].
Another interesting Opamp style filter system is in the LHXS fender and marshall emulators, particularly the cabinet sim sections..not that they can or should be lifted directly, but shows something to look at.
Comb filter...[?...nice control but gets a big parts count quick].
Adjustable LP filter [pot 'n cap from SP to ground] simple, somewhat effective.
OT:...>lol<?...I have recurring thoughts of a very small scale amplifier driving a scaled down inductor, to 'simply' [lol] scale down the mechanics of amp>speaker>mic>amp system...get some actual moving inductors in there..that's the first big catch...where to find a scale models of your favorite speaker, transformers etc.
..driver could be a reverb transducer? VU with most of sprung weight-needle removed?]
...mechanically [or through air] suspended-dampened-coupled to an inductor [microphone element?..reverb coil? used as pickup...

[Steve Conner]

I once made a speaker simulator box using an old phone line isolating transformer as a bandpass filter.

http://scopeboy.com/ssim.html

It just looks like a 2 pole highpass followed by a 2 pole lowpass, so it's nothing special, but it sounded OK. The lowpass section takes out most of the buzz, while the highpass tries to mimic the crappy bass response of the usual guitar cabinet. I drove the transformer as hard as possible to try and get some saturation, too.

The transformer I used is discontinued, so I leave it as an exercise to the reader to find a replacement :P It has high leakage inductance on account of its double chambered bobbin, and low magnetizing inductance because of the air gap needed to take the DC line current.

I don't see the point in accurate speaker simulators anyway, the experience of a cranked tube amp coupled to a human ear is so complicated and non-linear (and fun!) that it's easier just to find somewhere you can crank one without getting into trouble. A speaker simulator just needs to be a rough thing for practice.

Even then, I managed to get my homebuilt amps to give out reasonable tones at levels that don't bug the neighbours, as well as flat out, so I don't use the simulator any more. I think an amp flexible enough to sound good over a wide range of volumes is a neater thing to have than a speaker simulator, any time.

[TigerG]

Thanks for the suggestion Steve. I'm with you on the simulator thing--I'm not looking to emulate the sound of a speaker. I just need something that'll smooth out a buzzy line out on those occasions I need to record quietly, without a speaker, shhh.

[MarkusBass]

Tiger,

The Web site mentioned by Teemu is Polish (which can be discovered by looking at the domain name - especially the extension .pl). You may try to look at: http://www.herby.kielce.pl/~piter where you can find English version of the site. Since I know the language, I could try to translate the page mentioned by Teemu but this may take some time. In general the page contains description of various cabinet simulators starting from the simplest one to the most advanced. The most advanced simulator described at the end of the page is from http://home3.netcarrier.com/%7Elxh2/ Web site (I think it is considered as the most complex and the most accurate). For every cabinet simulator you have a schematics (under "schemat" link - "schemat" in Polish means exactly schematics in English - not to difficult to guess) and frequency diagram.
On the LXH2 Web site you can listen at sound clips, which are quite impressive.

Marek

[MarkusBass]

Tiger,

I've just noticed your initial question:

Originally Posted by TigerG

Anybody have any good, simple speaker emulator/simulator designs?

It's difficult to meet both requirements. Simple speaker simulators are described at the beginning of the Web site mentioned by Teemu. Good simulators are described at the end of the page - but they are not simple. You can't have both.

Marek