<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2004-02-25</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000725897</issuerCik>
        <issuerName>CIRCUIT RESEARCH LABS INC</issuerName>
        <issuerTradingSymbol>CRLI</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001194649</rptOwnerCik>
            <rptOwnerName>ZENI PHILLIP T</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1></rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity></rptOwnerCity>
            <rptOwnerState></rptOwnerState>
            <rptOwnerZipCode></rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Executive VP and COO</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock, $.10 par value</value>
            </securityTitle>
            <transactionDate>
                <value>2004-02-25</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>9368</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.7185</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>652153</value>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Per the Reporting Person's employment agreement with the Issuer, effective
October 1, 2002, the Reporting Person's compensation consists of cash and
restricted stock.  Under the employment agreement, the restricted stock is
granted on a monthly basis at an issue price equal to the average of the daily
closing price of the Issuer's common stock during the month preceding the grant.</footnote>
        <footnote id="F2">Includes 50,000 shares of common stock subject to exercisable options and
previously reported on a Form 4 filed by the Reporting Person on February 11,
2002.</footnote>
        <footnote id="F3">Includes 200,000 shares of common stock subject to exercisable options and
previously reported on a Form 4 and Schedule 13D filed by the Reporting Person on October 22, 2003.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Phillip T. Zeni, Sr.</signatureName>
        <signatureDate>2004-02-25</signatureDate>
    </ownerSignature>
</ownershipDocument>
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X0201
4
2004-02-25
0
0000725897
CIRCUIT RESEARCH LABS INC
CRLI
0001194649
ZENI PHILLIP T
1
1
1
0
Executive VP and COO
Common Stock, $.10 par value
2004-02-25
4
A
0
9368
0.7185
A
652153
D
Per the Reporting Person's employment agreement with the Issuer, effective
October 1, 2002, the Reporting Person's compensation consists of cash and
restricted stock.  Under the employment agreement, the restricted stock is
granted on a monthly basis at an issue price equal to the average of the daily
closing price of the Issuer's common stock during the month preceding the grant.
Includes 50,000 shares of common stock subject to exercisable options and
previously reported on a Form 4 filed by the Reporting Person on February 11,
2002.
Includes 200,000 shares of common stock subject to exercisable options and
previously reported on a Form 4 and Schedule 13D filed by the Reporting Person on October 22, 2003.
/s/ Phillip T. Zeni, Sr.
2004-02-25