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Eminence Sigma Pro-18A v1 Spec Sheet

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Category: General
Forum Name: General Forum
Forum Description: Open Discussion / Questions
URL: https://forum.speakerplans.com/forum_posts.asp?TID=109226
Printed Date: 27 March 2026 at 9:30am
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Topic: Eminence Sigma Pro-18A v1 Spec Sheet
Posted By: ethnbh0110
Subject: Eminence Sigma Pro-18A v1 Spec Sheet
Date Posted: 11 September 2025 at 3:04pm
Hi all,

I have a pair of both the Eminence Sigma Pro 18-A v1s and v2s. I am struggling to find specs for the v1s anywhere online. Eminence only advertise the spec sheet for the v2 and there doesn't seem to be any record of the v1 which were released in the 90s and have a purple label on the back. Reaching out to see if anyone here has a spec sheet for them or has any leads on why there isn't any existing information about them. I am cautious about treating them as if there the same driver because they look physically different and the v2 will likely be an upgrade or a solution to an issue with the v1.

Cheers,
Ethan



Replies:
Posted By: APC321
Date Posted: 11 September 2025 at 4:49pm
Try emailing Eminence on info@eminence.com

I have found them very helpful for answers to this kind of question.


Posted By: ethnbh0110
Date Posted: 11 September 2025 at 4:58pm
Hi,

Thanks for your prompt reply. I have emailed eminence but they haven’t got back yet, only with an automated message saying to read their FAQs. Maybe I just need to be a bit more patient, haha!

Cheers
Ethan


Posted By: APC321
Date Posted: 11 September 2025 at 5:46pm
I hope that Eminence give you an answer to your question, rather than being yet another audio company to reduce it's customer service.

Fingers crossed...


Posted By: ethnbh0110
Date Posted: 11 September 2025 at 6:07pm
Appreciate the advice, and I hope so too!


Posted By: cravings
Date Posted: 11 September 2025 at 6:10pm
from archive.org, 2002

Nominal Basket Diameter      
18", 457.2mm
Impedance      
8 ohm
Power Rating      500W rms
Resonance      28Hz
Usable Frequency Range      25Hz - 2.5kHz
Average Sensitivity 1W @ 1m      100 dB
Magnet Weight      95oz.
Gap Height      0.375", 9.52mm
Voice Coil Diameter      3", 76.2mm


Mounting Information Overall Diameter      18", 457.2mm
Baffle Hole Diameter      16.56", 420.5mm
Front Sealing Gasket      fitted as standard
Rear Sealing Gasket      fitted as standard
Mounting Holes Diameter      0.25", 6.4mm
Mounting Hole B.C.D.      17.25", 438.2mm
Depth      8.15", 207mm
Shipping Weight      27.2 lbs, 12.4 kg


Thiele-Small Parameters Resonant Frequency      28Hz
Impedance (RE)      6.29 ohm
Coil Inductance (Le)      1.90mH
Electromagnetic Q (Qes)      0.30
Mechanical Q (Qms)      8.28
Total Q (Qts)      0.29
Compliance Equivalent Volume (Vas)
     441.2 liters
15.58 cu. ft.
Peak Diaphragm Displacement
Volume (Vd)      688cc
Mechanical Compliance
of suspension (Cms)      0.24mm/N
BL Product (BL)      22.1 T-M
Diaphragm Mass inc. Airload (Mms)      130 grams
Equiv. Resistance of mechanical suspension loss (Rms)      2.81N*sec/M
Efficiency Bandwidth Product (EBP)      95
Voice Coil Overhang (Xmax)      6.0mm
Surface Area of Cone (Sd)      1140.1cm2
Impedance at Resonance (Zmax)      180 ohm

Materials of Construction

    Kapton coil former
    Ferrite magnet
    Die-cast aluminum basket

     

    Polyamide-imide coated copper voice coil
    Paper cone/cloth cone edge

    Solid composition paper dust cap


Posted By: ethnbh0110
Date Posted: 11 September 2025 at 6:58pm
You’re an absolute legend. Do you think you could send me the link to the archive page where you found them please?

Cheers
Ethan


Posted By: cravings
Date Posted: 11 September 2025 at 8:04pm
Archive.org

...


Posted By: ethnbh0110
Date Posted: 11 September 2025 at 8:53pm
I meant the url for the specific page but that’s fine. I will search it up myself.

Cheers
Ethan


Posted By: Lucasdude
Date Posted: 12 September 2025 at 12:16pm
https://archive.org/details/manualzz-id-1235190/mode/1up?q=eminence+sigma+pro18a" rel="nofollow - https://archive.org/details/manualzz-id-1235190/mode/1up?q=eminence+sigma+pro18a


Posted By: DMorison
Date Posted: 13 September 2025 at 3:33pm
Originally posted by cravings cravings wrote:

from archive.org, 2002


Note that apart from the reduced power handling, (500W vs 650W), those are the current specs per Eminence's website:  https://eminence.com/products/sigma_pro_18a?_pos=1&_sid=588aaf204&_ss=r#specifications" rel="nofollow - https://eminence.com/products/sigma_pro_18a?_pos=1&_sid=588aaf204&_ss=r#specifications

Now it might just be that the difference in power handling was the only difference between the older and current ones, but hopefully the OP will get the full info from Eminence in due course.



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