Archive for Loudspeakers

Celestion G12T-100 Guitar Speaker Driver

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Hello,

I recently got a Marshall JCM2000 DSL401 in the shop for repairs. This amp is equipped with a 12 inch Celestion speaker labeled GOLD BACK. On a side label you can find the G12T-100 markings tho.

Checking to see if the problem wasn’t with the speaker itself i measured it and got the T/S parameters and impedance curve. Subscribers will find that zma and frd files are available.

Parameters (pdf): celestion g12t-100

Celestion G12T-100 Marshall Gold Back

Celestion G12T-100 Marshall Gold Back

 

Thanks for visiting

 

Music and Audio Chain

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There were many discussions about what is the most important component in the music reproduction audio chain. I won’t get into that, we know everything is important but the better question i think is when starting an audio system what components should come first? Where should the investment start?

In my opinion, loudspeakers bring the greatest change in a system and therefore it seems the best choice of a first investment. The sonic differences are clear and the quality of reproduction can have a drastic increase when upgrading to real speakers.

So you want to build a better audio system and you set aside a specific budget for it. You are thinking perhaps to split it to get a good source (record player, cd player, reel to reel tape deck), a good amplifier and a good pair of loudspeakers. This would be a great way to do it if you have a really big budget. Most often than not tho that is not the case. With a limited amount of money at hand i would say to first invest it in a pair of loudspeakers. Especially if you still have an old amplifier and source from previous systems. You can use the new speakers in the old system for a while and still benefit greatly from the increased quality of reproduce sound. Then put aside money again and get the best amplifier to drive the speakers and then save more money and get a good source.

Then reason behind this way is that sources are more abundant. With the availability of high resolution formats you can live with PC-based sound for a while until you save for your favorite source. You can still enjoy better reproduction than your old system as opposed to getting a great record player and using less than good speakers.

With great speakers you immediately feel the increase in performance and this will give you a good feeling that you made the right investment. Money don’t come easy so you will look for an excuse in spending the money. Hearing the difference in sound will make up for that I’m sure.

Starting from the other end of the audio chain might not render such a big difference and you might loose confidence in spending money to upgrade your system.

When choosing components don’t hurry. Excitement can get you to take rush decisions, believe me, i know. Study, do your homework, go to audio expos listen and try out as many products as you can. Take notes, keep a record of what you hear, what you like, what you don’t, what surprised you, features and specs of anything you hear. Don’t rely on your memory. You will soon find out you like a certain type of sound and you will have a list of products that meet your requirements.

Hope it helps and thanks for visiting

JBL Everest DD66000 Bi-Amped with Accuphase

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Looking through some of my pictures, I remember a setup i really liked and i thought i should share it.

JBL DD66000 running bi-amped with Accuphase P-6100 driving Mid-High Drivers and M-6000 driving Low Drivers. This was presented when DF-55 crossover unit was introduced.

Hope you will enjoy the pictures.

JBL Everest  and Accuphase Bi-Amp Setup

JBL Everest and Accuphase Bi-Amp Setup

JBL Everest DD66000

JBL Everest DD66000

JBL Everest DD66000 also Avalon

JBL Everest DD66000 also Avalon

JBL Everest DD66000 2WAY

JBL Everest DD66000 2WAY

The Mighty Accuphase M-6000

The Mighty Accuphase M-6000

 

Thank you for visiting.

 

 

Electric Equivalent Model of Loudspeakers スピーカーの電気モデル

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Hello again,

In this article i will present a way to model the impedance of a speaker driver and how to use that in crossover design. Most crossover calculators on the internet assume a linear fixed impedance as the load of the filter but as you will see this is not the case. For this purpose I created a spreadsheet that will calculate the parameters for you.

The spreadsheet uses Electrical and Mechanical parameters of the loudspeaker driver and calculates the equivalent electrical component value to be used with any circuit simulation software (e.q. SPICE).

Re and Le are electrical components and describe the voice coil properties. Lces, Cmes and Res are mechanical components that are shifted via the BL coupling factor to the electrical side of the impedance model.

It is important to take this fact into consideration because more often than not the mechanical part of the impedance has an influence on the way the filter will respond.

In the below example you can see a standard L-R lowpass filter with a corner frequency of 1kHz. You can see the filter applied to a 8 ohm resistor in the way the most online calculators are being used and you can also see the filter applied to a complex load which represents the electrical model of the loudspeaker (without a box).

2nd order LR 1khz LPFNow lets look at the filters response ( dashed line represent the 8 ohm resistor load and the solid line represents the advanced electrical model load )

Compare Response of load on low pass filter

As you can see the differences cannot be negligible. Below you can find the attached spreadsheet that you can use to build the model. Also it can calculate the box influence for a closed box or bass reflex. The tree elements are connected in series and form  a branch that is connected in parallel to the mechanical equivalent components.

Electric Model of Loudspeakers

 

 

Paper Tweeter

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I had a little fun Sunday night while listening to Elvin Jones. Found a pair of small paper tweeters, seemed of german made, probably Grundig, i think used in higher quality TV sets.

I hooked them up via a 3.8uF capacitor and listened a bit. While not the most revealing sound i like their timbre and thought they are good for jazz. I measured their respomse and impedance and then hooked them to a pair of OB speakers i have with a single russian fullrange driver. Very old drivers but got them in great condition.

There sure is something about light paper pulp cones that i like alot. Is it transients, dynamics or sensitivity i dont know for sure but my guess the secret is somewhere along those lines.

Paper Tweeter

Paper Tweeter

Paper Tweeter

Paper Tweeter

Paper Tweeter

Paper Tweeter

You can see response starts falling with increasing frequency. This is a much disputed issue with audio enthusiasts. Some prefer it like this (me as well) some like it flatter some prefer a bit on the rise. Either way you can see the tweeter with a 40mm diameter radiating cone can hold up to almost 60 degree dispertion within 6dB. Pretty impressive and pretty linear power response.

I hooked it to the fullrange system with a 2.2uF MKP capacitor.

Thanks for visiting.

DALI Epicon6スピーカー

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DALI成分の写真。 小さなTHD磁気回路を見ることができます。

Components of DALI Epicon 6 loudspeaker. You can see the low distortion magnetic circuit.

Dali Epicon 6 スピーカー

dsc02167 dsc02168 dsc02169

Thank you for visiting, ご覧いただきありがとうございます。