DIY Home Hi-Fi kit with coaxial driver

Celeste is a full range home loudspeaker with Celestion coaxial driver, developed by Thomas Schmidt and Holger Barske as bass reflex system.

Featuring a TF1225CX coaxial driver, the coaxial system itself is no longer identifiable as the high frequency unit is hidden from view, under the dust protection.

The crossover consists of a second order high pass filter (12 dB per octave slope) and a 3rd order low pass filter.

Technical data

  • impedance: 8 Ohm
  • sensitivity (2,83V/1m): 94 dB
  • size (HxWxD): 610 x 520 x 387 mm
  • frequency range (-8dB): 35 – 20000 Hz
  • crossover frequency(s): 1900 Hz
  • speaker type: bass reflex

To find out more and to purchase the kit, go to Lautsprechershop, here.

Hi-Fi Speaker Kit Featuring FTR08-2011D

Designed by our good friends at Lautsprechershop and available as a built it yourself kit, Javari is a high performance loudspeaker system that can be configured for different situations: as a passive speaker, as an active solution and in a wide variety of modular setups – compact, XL and XXL.

What is it?

The heart of the Javari is a compact speaker which transforms into the high-midrange component of XL and XXL floor-standing configurations. A high efficiency Alcone AC 15 textile dome tweeter is paired with a Celestion FTR08-2011D, giving an astoundingly high overall efficiency of 93 dB.

Due to its high efficiency the Javari is a lot of fun to use, whether it is controlled by a tube amplifier or the broad dynamic range required for the home cinema. For the Javari XXL Tower, the Javari Top is accompanied by two subwoofer columns, each of one contains an Alcone AC 10 subwoofer driver.

The Javari Top uses a crossover of 2nd order (12 dB per octave slope). In this setup, the Javari top gets a first-order high-pass filter with large capacitors, the subwoofers are filtered via a second-order low-pass. The frequency response of the speaker is quite linear with a slight peak at 12 kHz.

At an average sound pressure level of 85 dB (1m), the non-linear distortions above 400 Hz are extremely low. At 95 dB SPL (1m) these distortions still are well controlled. The decay spectrum shows almost no irregularities except for some resonances around 500 Hz.

Technical data

  • impedance: 4 Ohm
  • sensivity (2,83V/1m): 94 dB
  • size (HxWxD): 1760 x 300 x 400 mm
  • frequency range (-8dB): 28 – 20000 Hz
  • crossover frequency(s): 150, 2200 Hz
  • speaker type: bass reflex

For more details, plans and a kit list, click here.

Open Back or Closed Back Cabinet – Which is for Me?

It’s widely known that loudspeaker choice can play a big part in your tone. What’s a little less well known is that many elements of the speaker cabinet’s construction also contribute. This includes the size of the cabinet, type of wood, thickness of baffle (the panel that the speaker is mounted to) and how the parts of cabinet are joined together.

Perhaps the most significant element of a cabinet’s construction, however, is whether the back is open or closed. Believe it or not the same amplifier will sound significantly different when driving speakers in either open back or closed back cabinets.

Open Back Cabinet

Most open back cabinets are actually just partially open, with upper and lower panels covering half or more of the back. They allow some of the speaker sound to radiate from the back and to a lesser extent, the sides.

In general open back cabs have a room filling quality that sounds open and natural. Without a complete back panel that compresses the speaker’s ‘voice’, open back cabinets might be considered a more organic representation of a guitar sound. High frequencies particularly benefit from this – they have lots of presence. The low end will tend to feel looser.

On stage, this wash of sound can be quite helpful when there are no monitors – your drummer might be grateful for that! In the studio it provides some excellent options in terms of microphone placement. A slightly different tonality will be available at the rear of the cab, and the use of an isolation booth can create a more complete soundscape than you could capture using multiple microphones.

Closed Back Cabinet

Unlike the open back cabinet, closed back cabs can really only project the sound forwards, meaning no back spill or side leakage from the cabinet. This tends to accentuate and harden midrange and bass sounds, giving them a greater amount of low end punch.

This increased directionality can make them harder to hear on stage unless you’re directly in front, but is a boon for sound-men who would otherwise have to contend with the ambient ‘wash’ produced by an open back cabinet.

Which is for Me?

At Celestion we’re often asked “which type of cabinet is best for me?”

As a rule of thumb, closed back cabinets tend to project the sound forwards and yield a punchier, more structured tone with crisper definition. Contrast that with open back cabinets that are much more inclined to fill the room they are in, providing a more natural and organic sound with a greater ambient quality.

Just like with all tone-based decisions, it ends up being subjective, it’s entirely dependent on what you like to listen to and the kinds of sounds you’re seeking. So with all the above information in mind, take every opportunity to play as many different types of cab as possible open back or closed back, as well as every kind of speaker you can find. Trust your ears and they’ll help you find what you like the sound of most.

Does (Speaker) Size Matter?

These days, guitar speakers are available in a range of sizes from two or three inches right up to 15-inch. Smaller speakers are great for bedroom blasters and practice amps where reduced output at low frequencies can minimize sound-‘spillage’ between rooms and keep the neighbours sweet.Probably the most popular format though, is the 12-inch speaker. But with an increasing range of quality 10-inch and some interesting 15-inch speakers available, we ask: “what role does speaker size play in the relentless pursuit of tone?”

Inside the Mind of the Speaker Designer

Practically all a guitar speaker’s constituent parts contribute in some way to its sonic signature. Chief among them are voice coil, magnet assembly and cone (but also influential are the suspension, surround, dustcap, cone treatments, etc) Each of these factors interact with the others, together contributing to overall tone. These interactions, though in some cases very complex, are governed by certain principles of physics, in particular:

1. Output level (a.k.a. sensitivity) is determined by how efficiently the speaker converts electrical energy into movement of air.

2. Sound dispersion is controlled by the directional nature of high frequency sound and the tendency of certain cone shapes to focus the output signal in different ways.

3. For guitar speakers in particular, vibration ‘modes’ within the body of the cone add much of the harmonic complexity and coloration that significantly contributes to great tone.

The speaker designer uses their expertise to find the right mix of all of these factors to hit a given ‘tone target.’

Imagine we want to use a small speaker with a thin and light cone. There would be more intense vibration modes within this type of cone (compared to a cone of greater thickness, which would be more resistant to these vibrations), resulting in a richer, more harmonically complex tonality. However, use the same cone thickness with a larger diameter speaker and that cone might lack sufficient stiffness to withstand the proposed power handling, and could buckle under the force of the moving voice coil.

In this situation there would need to be some ‘trade-off’ between tonality and power handling, requiring the designer to make both musical and technical choices to reach a desirable and workable solution. An experienced speaker designer will have the capability to identify the ‘right’ choices to make in these situations, and use the opportunity to create a completely new sounding speaker.

What This Means For Tone

So we see that attributes like size, harmonic complexity, power handling and high-note dispersion are clearly linked in the design process. Over time, the 12-inch speaker has come to be regarded as having the best balance of these attributes. However, 10s and 15s can offer some alternative, interesting and even exotic flavors!

Good sounding 10s can deliver a fast, punchy sound at wider listening angles with reduced ‘boom’ on small stages. They often offer increased portability, reduced cost and the ability to push your amp into overdrive at reasonable levels without having drumsticks aimed at the back of your head!

A well-designed 15 can move more air so you can gig those wonderful little valve amps. The vocal range can be creamier, with extended low end and lots of detail and harmonic complexity. It can give surprising richness to some otherwise scratchy-sounding guitar and amp combinations.

Which Size for You?

Changing speakers can have a greater impact on tone than swapping guitar, pickup, or even amplifier. So ask yourself, why just one size of speaker? As players all we need do is select the right one according to situation, application and desire.

> For the recording or practice session: why not try a small amp through a sweet well-balanced 10.
> At your big break support gig on the city hall stage: how about a 4 x 12!
> Need to add some beef to your retro ‘plasticaster’ use your 1 x 15 cabinet.

What’s more, just as boutique amp makers have mixed different models to increase harmonic detail, why not take this a step further and mix 10s, 12s and even 15s to create that unique signature sound!

Dual Subwoofer Design (Bass Reflex)

CF1840JD Basic Parameters: Vas: 113.9; Qts: 0.44; Fs: 44.20; SPL: 98.00

Number of drivers: 2

Box type: Vented – 0.195 m length, 12.00 x 90.00 cm rectangle

Box size: 1.5 inch thickness for solid construction.

SPL inside the box at 1000w (approximate): 131 dB.
Speakers connected in parallel to obtain 4 ohms.

Check out the full design information in the attached PDF.

Build This! Dual Subwoofer

For this competition, I’ve choose to design a sub with high level capability, something that can compete with an F218 Funktion One in terms of SPL and low response. Yes, it is a great challenge with a speaker which has a Qes of 0.496, but I like challenges.

I’ve designed an hybrid horn/reflex. I’ve already built this type of cabinet: They sound right with very high level sound pressure, great dynamic. A lot of people in France love them and they are easy to build.

I use software like Akabak, Hornresp to make simulations. I well know them, they are quite accurate if properly set.

The sensitivity is 104.5dB 1w (2 volts 4 ohms) @ 1m

Theoretical maximum continuous SPL: 137.5dB and 143.5dB peak

Low response:
One cabinet :
43Hz -3dB
39Hz -6dB
35Hz -10dB
Four cabinets :
38Hz -3dB
34Hz -6dB
29Hz -10dB

Recommended high pass filter: 34Hz 24dB/oct Butterworth
Ports are properly sized to not hear air noise at high pressure level.

Carlos Santana Rig Rundown

After being retired from use for some time, Santana’s original, snakeskin-covered 100-watt Mesa/Boogie is back onstage with the master. Santana also plays through a pair of Dumble Overdrive Reverbs and a pair of Bludotone Universal Tone heads, one of which is a prototype.

The amps drive a pair of paisley-covered PRS 4×12 cabs. One cab is loaded with four Celestion Vintage 30s, the other sports two Celestion Vintage 30s and two Celestion G12-65s.

Cabinet Handbook

This handbook covers all the major kinds of cab types you’re likely to want to try and build. Anything from horn-loaded subwoofers to 4×12 guitar cabs, along with advice on dimensions, fixings materials and construction.

There are useful sections on porting and crossover design including some basic scientific theory to help you make the right choices for your application.

For more advice on choosing PA speakers, click here.

For more advice on choosing guitar speakers, click here.

Speaker Wiring Configurations

Replacing a speaker or speakers in your cab can be a really cost-effective way of significantly upgrading your tone. If you’re thinking of swapping out speakers yourself, then you’ve come to the right place! It needn’t be a difficult operation, but it’s important to be aware of how the speakers are connected up, as well as some of the implications of wiring up multiple speakers together. Before you get to re-loading your cab.. take a moment to read through the important background information below and get ready to take a step closer to great tone!

Single Speaker

The most basic cabinet configuration is a single speaker.

1 x 8 ohm Speaker = 8 ohm load
1×16 ohm speaker = 16 ohm load

Two Speakers

1. Match impedances (ohms) – all speakers in the same box should have the same impedance.

2. Power handling – as a rule of thumb, when mixing speaker types in a two speaker cabinet, maximum power handling is 2 x the lowest rated speaker (e.g. for 30-watt & 60-watt speakers, max power handling = 2×30-watt = 60-watt)

There are two ways you can wire a two speaker cabinet.


Series: 2 x 4 Ohm Speaker = 8 Ohm Load;

2 X 8 Ohm Speaker = 16 Ohm Load;

2 X 16 Ohm Speaker = 32 Ohm Load


Or, in Parallel: 2 X 4 Ohm Speaker = 2 Ohm Load;

2 X 8 Ohm Speaker = 4 Ohm Load;

2 X 16 Ohm Speaker = 8 Ohm Load

Four Speakers

1. Match impedances (ohms) – all speakers in the same box should have the same impedance

2. Power handling – as a rule of thumb, when mixing speakers in a four speaker cabinet, maximum power is 4 x the lowest rated speaker (e.g. for 2×30-watt & 2×60-watt speakers, max power handling = 4×30-watt = 120-watt)

There are two ways you can wire a 4×12 (or 4×10 for that matter), the main one is Series/Parallel: 4 X 8 Ohm Speaker = 8 Ohm Load; 4 X 16 Ohm Speaker = 16 Ohm Load

Power Handling: All you need to know!

Different speaker manufacturers use differing methods to determine power handling. At Celestion, every speaker is rigorously power/longevity tested using an in-house developed noise source. From this test, we find out how much power the speaker is capable of using and how much will destroy the speaker outright. By skilful analysis of the test data, we calculate a suitable power-handling figure.

The value chosen is low enough so there’s little or no risk of damage, but highenough for the speaker to fulfil the application it was designed for. It is NOT an absolute limit above which you must never go, more like a “speed limit” You can exceed the limit if you want, but it’s not recommended and if you do, theremay be trouble ahead…Generally, you can safely run a 60-watt Celestion speaker at 60 watts and it’ll keep going all day long.* Connect it up to 100 watts and it might work for anhour or more before it incinerates. “Over-power” any speaker and it’ll workfine for a while; just don’t bank on it lasting.

(* Extreme use can break a speaker at lower-than-rated power levels. Forexample a sustained drop-tuned Metalcore pummelling through vintage-typespeakers would almost certainly cause damage.)

Power Handling for Combined Speakers

If you mix different speakers with different power ratings in the same cabinet, it’s important to be aware of the combined power handling of the cabinet itself. Unfortunately it’s not quite as simple as adding together the two power handling values.

As a rule of thumb, the cabinet power handling should be calculated as a multiple of the lowest rated speaker. For example in a 2×12 containing a 60-watt speaker and a 30-watt speaker, overall cabinet power handling is 2×30-watt = 60-watt. In a 4×12 containing 2×60-watt speakers and 2×30-watt speakers, overall cabinet power handling is 4×30-watt = 120-watt.