Custom Micro Speaker vs Standard Speaker: Which Is Better for OEM Products?
1. Three Routes, and What Each One Actually Costs
Short answer: Stock, modified and new-tooling routes differ in which cost element dominates. Most programmes only need the first two, and many only need the first.
The three routes are usually described by what changes. It is more useful to describe them by what they cost. A stock part costs unit price and nothing else. A modified standard part costs unit price plus the parameter change, which is usually small and does not involve tooling. A new-tooling part costs unit price plus tooling, plus the schedule that tooling introduces.
The practical consequence is that the middle route is under-used. Diaphragm thickness, voice-coil layer count and wire gauge, dome material, surround material and thickness, magnet grade and secondary magnet, port or cavity geometry, and termination are all parameters that can normally be adjusted on an existing platform. A programme that needs one of these changed is not buying a custom part in the expensive sense; it is buying a parameter change on a validated platform.
The third route is justified when the driver's outline itself has to change, and that is rarer than programmes expect. When it is justified, the relevant question is not whether the tooling cost is acceptable in isolation but what it buys relative to the alternatives, including the option of restructuring the product to accept a different outline.
2. When a Standard Part Already Covers the Requirement
Short answer: A standard part is sufficient when its published conditions match the product's. The comparison is between the published basis and the product's actual conditions, not between two part numbers.
A standard part covers the requirement when the published figures describe conditions the product will actually provide. That means the cavity volume in the published figure matches the volume the structure can seal, the mounting height matches what the product can give up, the termination matches what the assembly process accepts, and the measurement basis matches the conditions the product will be tested under.
This is a stricter test than it sounds, and it is where standard parts most often fail silently. A driver published in a 1 cc BOX does not describe the same system as the same driver in a 4 cc BOX, and a programme that takes the figure without its cavity condition has taken a number that does not apply. Where a catalogue states different cavity volumes for the sensitivity and resonance figures of the same model, the two numbers do not even describe the same installed state as each other.
The useful discipline is to read the published basis as part of the specification. A figure with its frequency, distance, drive voltage, cavity volume and mounting surface is comparable. A figure without them is a number that happens to be printed near a model name.
3. When a Standard Part Stops Working
Short answer: A standard part stops working when the binding constraint is the contact method, the cavity volume, or a parameter that cannot be moved on the existing platform.
1. The contact method. A product whose assembly cannot accept solder is limited to the spring-contact and lead-wire pool, which is a small fraction of a published catalogue. At one diameter it can be a single model, and if that model's construction cannot meet the requirement, substitution within the pool will not help.
2. The cavity volume. If the installed resonance computed from the available volume is already above target, no standard driver changes that. The volume has to come from the structure.
3. A parameter that cannot be moved. A spring-contact tool of fixed height cannot carry a compound diaphragm, because the diaphragm needs more travel than the height allows. No substitution among drivers in that tool helps, because they all share the height limit.
4. The measurement basis. If the product cannot reproduce the published measurement conditions, the published figures cannot be used to accept the part, and a different basis has to be agreed.
In each of these cases the constraint is not the part's acoustic performance. It is something the part cannot change about itself, which is why the answer is usually not a different catalogue model but a different approach — an adapter, a structural change, or a parameter change on a platform.
4. The Cost Elements Behind Each Route
Short answer: Unit price, tooling and schedule are the three elements. Which one dominates depends on volume and on whether the change needs tooling, and the answer is often counter-intuitive.
Table 1 sets out the cost elements by route. The point of reading it this way is that the same requirement can be cheap or expensive depending on which element dominates, and that is determined by volume and by whether the change needs tooling rather than by whether the part is called custom.
Table 1: Cost elements by route.
Route | What changes | Cost elements involved | When it is the right answer |
Stock part | Nothing | Unit price only | The published conditions match the product's, and the contact method and cavity are already compatible |
Modified standard part | One or more parameters on an existing platform: diaphragm thickness, coil layers or wire gauge, dome material, surround material and thickness, magnet grade or secondary magnet, port or cavity geometry, termination | Unit price plus the parameter change; normally no tooling | The acoustic target is reachable by moving parameters, and the outline and contact method are already compatible |
New outline | The driver's outline itself | Unit price plus tooling plus schedule | The product cannot accommodate any existing outline, and restructuring the product is more expensive than the tooling |
5. Reading a Published Range as Routes, Not Just Parts
Short answer: A published range shows which dimensions are already available, which tells you whether your requirement is a selection, a parameter change, or a new outline.
Table 2 lists the published dimensions across one sample catalogue, read as routes rather than as specifications. A requirement inside these options is a selection. A requirement that needs one parameter moved is a modification. A requirement that needs an outline not in the list is a new tooling decision, and that is the only case where the expensive route applies.
Table 2: Published dimensions across a sample catalogue, read as routes.
Dimension | Published options in the range | A requirement inside this is | A requirement outside this is |
Rated impedance | 4 Ω, 7 Ω, 8 Ω, 32 Ω | A selection | A parameter change, normally available |
Rated power | 0.05 W, 0.5 W, 0.8 W, 1.0 W, 2.0 W, 2.5 W, 3.0 W, 5.0 W, 10.0 W | A selection within a power class | A parameter change, subject to the amplifier's voltage |
Test voltage in published figures | 1.26 V, 2.0 V, 2.53 V, 2.83 V, 3.16 V, 3.46 V, 4.0 V, 4.47 V, 6.32 V | Directly comparable against your own test conditions | A request for a different basis, which has to be stated |
F0 tolerance as published | ±15% across the range | Directly usable | A tighter tolerance, which is a manufacturing decision with cost |
Cavity volume in published BOX figures | 1 cc, 2 cc, 3 cc, 4 cc | Comparable against the volume your structure can seal | A structural question, not a driver question |
Termination | Solder type, leaf spring or spring contact, lead wire | A selection, normally changeable on an existing platform | A parameter change, usually one of the cheaper ones |
Driver outline | φ13 to φ76 mm, and 8 × 9 mm to 40 × 20 mm rectangular | A selection | A new outline, which is the case that involves tooling |
Project Case Study (Hongsheng) — A Parameter Change, Not a New Part
The requirement came from a compact projector, where the customer needed audible level with reduced wind noise from the cooling path. The original solution delivered insufficient level and lacked low-frequency impact, and repeated driver substitutions had not resolved it. The programme had been running as a search for a better standard part.
The root cause was structural rather than a matter of part selection. The bass reflex path is tuned by its port, and the port tuning frequency depends on its cross-sectional area. That cross-section was shared with the product's airflow requirement, so the acoustic design could only ask for about a 10% increase. The tuning frequency therefore stopped at 150 Hz against an ideal of 180 Hz. No standard driver changes that, because the limit was in the mechanical design rather than in the component.
Once that was established, the route changed. Instead of searching for a different outline, three parameters were adjusted on an existing platform, which is the middle route rather than the expensive one. A 45 mm driver with a polyurethane surround was selected to raise midrange level, and a copper-clad aluminium voice coil reduced moving mass. A surround thickness of 0.12 mm brought the driver's own free-air resonance to 160 Hz, preserving low-frequency impact despite the port tuning being lower than ideal. At the port outlet, acoustic damping material was added, which reduced the wind noise by roughly two thirds without noticeably reducing bass output — a treatment that acts on the flow noise at the exit rather than on the tuning frequency.
Three distinct frequencies apply in this design and were kept separate throughout, because conflating them is the most common specification error when a parameter change is being evaluated. The driver's own free-air resonance is 160 Hz. The installed system resonance, measured after assembly with the cavity and port, is 250 Hz ±15%. The port tuning frequency is 120 Hz before the cross-section increase and 150 Hz after it. None of the three substitutes for another, and a specification that mixes them will not match the measurement.
Measurement confirms the electrical side as well. The published sensitivity is 105 ± 3 dB at 5.65 Vrms at 10 cm, and 5.65² / 4 = 7.98 W, which matches the 8.0 W rating of the configuration, so the driver is operating at its rated point rather than above it. The unit is rated 8.0 W with a 10 W maximum in an 80 cc cavity.
The programme is in production with 20,000 units shipped. The engineering work also reduced unit cost by 0.6 RMB in total, from three sources: a 0.2 RMB saving from the polyurethane surround, 0.1 RMB from replacing screws with adhesive, and 0.3 RMB from production efficiency, which amounts to 12,000 RMB across the shipped quantity. No new tooling was required for the driver. The transferable conclusion is that the route was decided by identifying which cost element dominated, and in this case it was a parameter change on an existing platform rather than a new part.
The programme started as a search for a better standard part and ended as three parameter changes on an existing platform. The constraint was a port cross-section shared with an airflow path, which no catalogue driver could change.
Hongsheng can also state which parameter has to move first when a target cannot be met on an existing platform, which is usually the question that decides the route.
6. Deciding the Route
Short answer: Four questions decide the route, and they can be answered before any part is selected: what the product cannot change, whether the published basis matches, which parameter has to move, and whether an existing outline fits.
5. What can the product not change? Thickness, keep-out volumes, the acoustic opening surface and the contact method. These are fixed before the route is chosen, and they decide whether an existing outline is even a candidate.
6. Do the published conditions match the product's? Cavity volume, mounting height, termination and measurement basis. If they match, the stock route is open.
7. Which parameter has to move, and can it move on an existing platform? If the answer is yes, the modified route is open and no tooling is involved.
8. Is there an existing outline the product can accommodate? If yes, the new-tooling route is not justified, however different the parameters are.
7. FAQ: Custom vs Standard Micro Speakers
Q1: Is a custom speaker always more expensive than a standard one?
No. A custom part is more expensive when the change that made it custom requires new tooling. A parameter change on an existing platform — diaphragm thickness, coil winding, dome or surround material, magnet grade, termination — normally costs little more than the stock part and involves no tooling.
Q2: When is a standard part the wrong choice?
When its published conditions do not match the product's. A driver published in a 1 cc BOX does not describe the same system as the same driver in a 4 cc BOX, and a figure taken without its cavity condition is a number that does not apply to your product.
Q3: How do I know whether I need new tooling?
Ask whether an existing outline can accommodate the requirement. Tooling is involved only when the driver's outline itself has to change. If an existing outline fits, the change is a parameter change and the tooling question does not arise.
Q4: What if the contact method rules out every candidate?
Then the pool is the constraint, not the part. An adapter that carries the contacts on a flexible printed circuit can preserve the assembly process while freeing the driver from a tool's height limit, which is what makes a different construction possible without changing the customer's assembly.
Q5: Does a tighter tolerance mean a custom part?
Not necessarily. A tighter tolerance is a manufacturing decision with a cost, and it can often be applied to an existing platform. Published configurations in one catalogue state ±15% on resonance; anything tighter has to be agreed rather than assumed.
Q6: Can a parameter change make the part worse?
It can move the result in an unintended direction, which is why each change should be measured. Moving the diaphragm thinner lowers the resonance but reduces mechanical margin; adding coil layers lowers the resonance but raises mounting height. The direction of each is predictable; the magnitude has to be measured.
Q7: What decides the route in the end?
Which cost element dominates. If the product's constraints are already compatible with a published configuration, the stock route is cheapest. If one parameter has to move, the modified route is usually cheap. Only when no existing outline fits does the tooling route apply.
Hongsheng publishes configurations across impedance, power and termination classes with the measurement basis and cavity condition stated for each, so a product's constraints can be matched against a published option before the route is chosen.
8. Summary: Decide the Cost Structure, Then the Route
Custom and standard are labels on parts, not descriptions of cost. What decides the route is which cost element dominates: unit price alone for a stock part, unit price plus a parameter change for a modified part, and unit price plus tooling plus schedule only when the outline itself has to change. Most programmes need the first two routes, and many need only the first — provided the published conditions genuinely match the product's, including the cavity volume, the mounting height, the termination and the measurement basis.
The failure mode to avoid is treating a standard part as safe without checking its conditions, and treating a custom part as expensive without checking whether the change actually needs tooling. Both mistakes send programmes down the wrong route, and both are avoidable by asking what the product cannot change, whether the published basis matches, which parameter has to move, and whether an existing outline fits. Hongsheng publishes configurations across impedance, power and termination classes with the measurement basis and cavity condition stated for each, so a product's constraints can be matched against a published option before the route is chosen.
Next step If you are deciding between a standard and a custom micro speaker for an OEM product, the shortest route to a configuration worth testing is to state five things: the space available for the driver and its cavity, the impedance the amplifier will drive, the power the rail can supply, the level required at the intended listening position, and the dimension your product cannot change. With those specified, our engineering team can recommend a suitable configuration for evaluation, or state plainly which part of the acoustic design has to change first.
More in This Series
· Micro Speaker Customization: What Can Actually Be Changed, and What It Costs → https://www.hsdz-spk.com/news/591.html
· How Much Does a Custom Micro Speaker Cost? A Cost-Structure Breakdown → https://www.hsdz-spk.com/news/593.html